particle.c

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2007 by Janne Karhu.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <stdlib.h>
#include <math.h>
#include <string.h>

#include "MEM_guardedalloc.h"

#include "DNA_curve_types.h"
#include "DNA_group_types.h"
#include "DNA_key_types.h"
#include "DNA_material_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_particle_types.h"
#include "DNA_smoke_types.h"
#include "DNA_scene_types.h"
#include "DNA_dynamicpaint_types.h"

#include "BLI_blenlib.h"
#include "BLI_math.h"
#include "BLI_utildefines.h"
#include "BLI_kdtree.h"
#include "BLI_rand.h"
#include "BLI_threads.h"
#include "BLI_linklist.h"
#include "BLI_bpath.h"

#include "BKE_anim.h"
#include "BKE_animsys.h"

#include "BKE_boids.h"
#include "BKE_cloth.h"
#include "BKE_effect.h"
#include "BKE_global.h"
#include "BKE_group.h"
#include "BKE_main.h"
#include "BKE_lattice.h"

#include "BKE_displist.h"
#include "BKE_particle.h"
#include "BKE_object.h"
#include "BKE_material.h"
#include "BKE_key.h"
#include "BKE_library.h"
#include "BKE_depsgraph.h"
#include "BKE_modifier.h"
#include "BKE_mesh.h"
#include "BKE_cdderivedmesh.h"
#include "BKE_pointcache.h"
#include "BKE_scene.h"
#include "BKE_deform.h"

#include "RE_render_ext.h"

static void get_child_modifier_parameters(ParticleSettings *part, ParticleThreadContext *ctx,
                ChildParticle *cpa, short cpa_from, int cpa_num, float *cpa_fuv, float *orco, ParticleTexture *ptex);
static void do_child_modifiers(ParticleSimulationData *sim,
                ParticleTexture *ptex, ParticleKey *par, float *par_rot, ChildParticle *cpa,
                float *orco, float mat[4][4], ParticleKey *state, float t);

/* few helpers for countall etc. */
int count_particles(ParticleSystem *psys)
{
    ParticleSettings *part=psys->part;
    PARTICLE_P;
    int tot=0;

    LOOP_SHOWN_PARTICLES {
        if(pa->alive == PARS_UNBORN && (part->flag & PART_UNBORN)==0);
        else if(pa->alive == PARS_DEAD && (part->flag & PART_DIED)==0);
        else tot++;
    }
    return tot;
}
int count_particles_mod(ParticleSystem *psys, int totgr, int cur)
{
    ParticleSettings *part=psys->part;
    PARTICLE_P;
    int tot=0;

    LOOP_SHOWN_PARTICLES {
        if(pa->alive == PARS_UNBORN && (part->flag & PART_UNBORN)==0);
        else if(pa->alive == PARS_DEAD && (part->flag & PART_DIED)==0);
        else if(p%totgr==cur) tot++;
    }
    return tot;
}
/* we allocate path cache memory in chunks instead of a big continguous
 * chunk, windows' memory allocater fails to find big blocks of memory often */

#define PATH_CACHE_BUF_SIZE 1024

static ParticleCacheKey **psys_alloc_path_cache_buffers(ListBase *bufs, int tot, int steps)
{
    LinkData *buf;
    ParticleCacheKey **cache;
    int i, totkey, totbufkey;

    tot= MAX2(tot, 1);
    totkey = 0;
    cache = MEM_callocN(tot*sizeof(void*), "PathCacheArray");

    while(totkey < tot) {
        totbufkey= MIN2(tot-totkey, PATH_CACHE_BUF_SIZE);
        buf= MEM_callocN(sizeof(LinkData), "PathCacheLinkData");
        buf->data= MEM_callocN(sizeof(ParticleCacheKey)*totbufkey*steps, "ParticleCacheKey");

        for(i=0; i<totbufkey; i++)
            cache[totkey+i] = ((ParticleCacheKey*)buf->data) + i*steps;

        totkey += totbufkey;
        BLI_addtail(bufs, buf);
    }

    return cache;
}

static void psys_free_path_cache_buffers(ParticleCacheKey **cache, ListBase *bufs)
{
    LinkData *buf;

    if(cache)
        MEM_freeN(cache);

    for(buf= bufs->first; buf; buf=buf->next)
        MEM_freeN(buf->data);
    BLI_freelistN(bufs);
}

/************************************************/
/*          Getting stuff                       */
/************************************************/
/* get object's active particle system safely */
ParticleSystem *psys_get_current(Object *ob)
{
    ParticleSystem *psys;
    if(ob==NULL) return NULL;

    for(psys=ob->particlesystem.first; psys; psys=psys->next){
        if(psys->flag & PSYS_CURRENT)
            return psys;
    }
    
    return NULL;
}
short psys_get_current_num(Object *ob)
{
    ParticleSystem *psys;
    short i;

    if(ob==NULL) return 0;

    for(psys=ob->particlesystem.first, i=0; psys; psys=psys->next, i++)
        if(psys->flag & PSYS_CURRENT)
            return i;
    
    return i;
}
void psys_set_current_num(Object *ob, int index)
{
    ParticleSystem *psys;
    short i;

    if(ob==NULL) return;

    for(psys=ob->particlesystem.first, i=0; psys; psys=psys->next, i++) {
        if(i == index)
            psys->flag |= PSYS_CURRENT;
        else
            psys->flag &= ~PSYS_CURRENT;
    }
}
Object *psys_find_object(Scene *scene, ParticleSystem *psys)
{
    Base *base;
    ParticleSystem *tpsys;

    for(base = scene->base.first; base; base = base->next) {
        for(tpsys = base->object->particlesystem.first; psys; psys=psys->next) {
            if(tpsys == psys)
                return base->object;
        }
    }

    return NULL;
}
Object *psys_get_lattice(ParticleSimulationData *sim)
{
    Object *lattice=NULL;
    
    if(psys_in_edit_mode(sim->scene, sim->psys)==0){

        ModifierData *md = (ModifierData*)psys_get_modifier(sim->ob, sim->psys);

        for(; md; md=md->next){
            if(md->type==eModifierType_Lattice){
                LatticeModifierData *lmd = (LatticeModifierData *)md;
                lattice=lmd->object;
                break;
            }
        }
        if(lattice)
            init_latt_deform(lattice, NULL);
    }

    return lattice;
}
void psys_disable_all(Object *ob)
{
    ParticleSystem *psys=ob->particlesystem.first;

    for(; psys; psys=psys->next)
        psys->flag |= PSYS_DISABLED;
}
void psys_enable_all(Object *ob)
{
    ParticleSystem *psys=ob->particlesystem.first;

    for(; psys; psys=psys->next)
        psys->flag &= ~PSYS_DISABLED;
}
int psys_in_edit_mode(Scene *scene, ParticleSystem *psys)
{
    return (scene->basact && (scene->basact->object->mode & OB_MODE_PARTICLE_EDIT) && psys==psys_get_current((scene->basact)->object) && (psys->edit || psys->pointcache->edit) && !psys->renderdata);
}
static void psys_create_frand(ParticleSystem *psys)
{
    int i;
    float *rand = psys->frand = MEM_callocN(PSYS_FRAND_COUNT * sizeof(float), "particle randoms");

    BLI_srandom(psys->seed);

    for(i=0; i<1024; i++, rand++)
        *rand = BLI_frand();
}
int psys_check_enabled(Object *ob, ParticleSystem *psys)
{
    ParticleSystemModifierData *psmd;

    if(psys->flag & PSYS_DISABLED || psys->flag & PSYS_DELETE || !psys->part)
        return 0;

    psmd= psys_get_modifier(ob, psys);
    if(psys->renderdata || G.rendering) {
        if(!(psmd->modifier.mode & eModifierMode_Render))
            return 0;
    }
    else if(!(psmd->modifier.mode & eModifierMode_Realtime))
        return 0;

    /* perhaps not the perfect place, but we have to be sure the rands are there before usage */
    if(!psys->frand)
        psys_create_frand(psys);
    else if(psys->recalc & PSYS_RECALC_RESET) {
        MEM_freeN(psys->frand);
        psys_create_frand(psys);
    }
    
    return 1;
}

int psys_check_edited(ParticleSystem *psys)
{
    if(psys->part && psys->part->type==PART_HAIR)
        return (psys->flag & PSYS_EDITED || (psys->edit && psys->edit->edited));
    else
        return (psys->pointcache->edit && psys->pointcache->edit->edited);
}

void psys_check_group_weights(ParticleSettings *part)
{
    ParticleDupliWeight *dw, *tdw;
    GroupObject *go;
    int current = 0;

    if(part->ren_as == PART_DRAW_GR && part->dup_group && part->dup_group->gobject.first) {
        /* first remove all weights that don't have an object in the group */
        dw = part->dupliweights.first;
        while(dw) {
            if(!object_in_group(dw->ob, part->dup_group)) {
                tdw = dw->next;
                BLI_freelinkN(&part->dupliweights, dw);
                dw = tdw;
            }
            else
                dw = dw->next;
        }

        /* then add objects in the group to new list */
        go = part->dup_group->gobject.first;
        while(go) {
            dw = part->dupliweights.first;
            while(dw && dw->ob != go->ob)
                dw = dw->next;
            
            if(!dw) {
                dw = MEM_callocN(sizeof(ParticleDupliWeight), "ParticleDupliWeight");
                dw->ob = go->ob;
                dw->count = 1;
                BLI_addtail(&part->dupliweights, dw);
            }

            go = go->next;  
        }

        dw = part->dupliweights.first;
        for(; dw; dw=dw->next) {
            if(dw->flag & PART_DUPLIW_CURRENT) {
                current = 1;
                break;
            }
        }

        if(!current) {
            dw = part->dupliweights.first;
            if(dw)
                dw->flag |= PART_DUPLIW_CURRENT;
        }
    }
    else {
        BLI_freelistN(&part->dupliweights);
    }
}
int psys_uses_gravity(ParticleSimulationData *sim)
{
    return sim->scene->physics_settings.flag & PHYS_GLOBAL_GRAVITY && sim->psys->part && sim->psys->part->effector_weights->global_gravity != 0.0f;
}
/************************************************/
/*          Freeing stuff                       */
/************************************************/
static void fluid_free_settings(SPHFluidSettings *fluid)
{
    if(fluid)
        MEM_freeN(fluid); 
}

void psys_free_settings(ParticleSettings *part)
{
    MTex *mtex;
    int a;
    BKE_free_animdata(&part->id);
    free_partdeflect(part->pd);
    free_partdeflect(part->pd2);

    if(part->effector_weights)
        MEM_freeN(part->effector_weights);

    BLI_freelistN(&part->dupliweights);

    boid_free_settings(part->boids);
    fluid_free_settings(part->fluid);

    for(a=0; a<MAX_MTEX; a++) {
        mtex= part->mtex[a];
        if(mtex && mtex->tex) mtex->tex->id.us--;
        if(mtex) MEM_freeN(mtex);
    }
}

void free_hair(Object *UNUSED(ob), ParticleSystem *psys, int dynamics)
{
    PARTICLE_P;

    LOOP_PARTICLES {
        if(pa->hair)
            MEM_freeN(pa->hair);
        pa->hair = NULL;
        pa->totkey = 0;
    }

    psys->flag &= ~PSYS_HAIR_DONE;

    if(psys->clmd) {
        if(dynamics) {
            BKE_ptcache_free_list(&psys->ptcaches);
            psys->clmd->point_cache = psys->pointcache = NULL;
            psys->clmd->ptcaches.first = psys->clmd->ptcaches.last = NULL;

            modifier_free((ModifierData*)psys->clmd);
            
            psys->clmd = NULL;
            psys->pointcache = BKE_ptcache_add(&psys->ptcaches);
        }
        else {
            cloth_free_modifier(psys->clmd);
        }
    }

    if(psys->hair_in_dm)
        psys->hair_in_dm->release(psys->hair_in_dm);
    psys->hair_in_dm = NULL;

    if(psys->hair_out_dm)
        psys->hair_out_dm->release(psys->hair_out_dm);
    psys->hair_out_dm = NULL;
}
void free_keyed_keys(ParticleSystem *psys)
{
    PARTICLE_P;

    if(psys->part->type == PART_HAIR)
        return;

    if(psys->particles && psys->particles->keys) {
        MEM_freeN(psys->particles->keys);

        LOOP_PARTICLES {
            if(pa->keys) {
                pa->keys= NULL;
                pa->totkey= 0;
            }
        }
    }
}
static void free_child_path_cache(ParticleSystem *psys)
{
    psys_free_path_cache_buffers(psys->childcache, &psys->childcachebufs);
    psys->childcache = NULL;
    psys->totchildcache = 0;
}
void psys_free_path_cache(ParticleSystem *psys, PTCacheEdit *edit)
{
    if(edit) {
        psys_free_path_cache_buffers(edit->pathcache, &edit->pathcachebufs);
        edit->pathcache= NULL;
        edit->totcached= 0;
    }
    if(psys) {
        psys_free_path_cache_buffers(psys->pathcache, &psys->pathcachebufs);
        psys->pathcache= NULL;
        psys->totcached= 0;

        free_child_path_cache(psys);
    }
}
void psys_free_children(ParticleSystem *psys)
{
    if(psys->child) {
        MEM_freeN(psys->child);
        psys->child= NULL;
        psys->totchild=0;
    }

    free_child_path_cache(psys);
}
void psys_free_particles(ParticleSystem *psys)
{
    PARTICLE_P;

    if(psys->particles) {
        if(psys->part->type==PART_HAIR) {
            LOOP_PARTICLES {
                if(pa->hair)
                    MEM_freeN(pa->hair);
            }
        }
        
        if(psys->particles->keys)
            MEM_freeN(psys->particles->keys);
        
        if(psys->particles->boid)
            MEM_freeN(psys->particles->boid);

        MEM_freeN(psys->particles);
        psys->particles= NULL;
        psys->totpart= 0;
    }
}
void psys_free_pdd(ParticleSystem *psys)
{
    if(psys->pdd) {
        if(psys->pdd->cdata)
            MEM_freeN(psys->pdd->cdata);
        psys->pdd->cdata = NULL;

        if(psys->pdd->vdata)
            MEM_freeN(psys->pdd->vdata);
        psys->pdd->vdata = NULL;

        if(psys->pdd->ndata)
            MEM_freeN(psys->pdd->ndata);
        psys->pdd->ndata = NULL;

        if(psys->pdd->vedata)
            MEM_freeN(psys->pdd->vedata);
        psys->pdd->vedata = NULL;

        psys->pdd->totpoint = 0;
        psys->pdd->tot_vec_size = 0;
    }
}
/* free everything */
void psys_free(Object *ob, ParticleSystem * psys)
{   
    if(psys){
        int nr = 0;
        ParticleSystem * tpsys;
        
        psys_free_path_cache(psys, NULL);

        free_hair(ob, psys, 1);

        psys_free_particles(psys);

        if(psys->edit && psys->free_edit)
            psys->free_edit(psys->edit);

        if(psys->child){
            MEM_freeN(psys->child);
            psys->child = NULL;
            psys->totchild = 0;
        }
        
        // check if we are last non-visible particle system
        for(tpsys=ob->particlesystem.first; tpsys; tpsys=tpsys->next){
            if(tpsys->part)
            {
                if(ELEM(tpsys->part->ren_as,PART_DRAW_OB,PART_DRAW_GR))
                {
                    nr++;
                    break;
                }
            }
        }
        // clear do-not-draw-flag
        if(!nr)
            ob->transflag &= ~OB_DUPLIPARTS;

        if(psys->part){
            psys->part->id.us--;        
            psys->part=NULL;
        }

        BKE_ptcache_free_list(&psys->ptcaches);
        psys->pointcache = NULL;
        
        BLI_freelistN(&psys->targets);

        BLI_bvhtree_free(psys->bvhtree);
        BLI_kdtree_free(psys->tree);
 
        if(psys->fluid_springs)
            MEM_freeN(psys->fluid_springs);

        pdEndEffectors(&psys->effectors);

        if(psys->frand)
            MEM_freeN(psys->frand);

        if(psys->pdd) {
            psys_free_pdd(psys);
            MEM_freeN(psys->pdd);
        }

        MEM_freeN(psys);
    }
}

/************************************************/
/*          Rendering                           */
/************************************************/
/* these functions move away particle data and bring it back after
 * rendering, to make different render settings possible without
 * removing the previous data. this should be solved properly once */

typedef struct ParticleRenderElem {
    int curchild, totchild, reduce;
    float lambda, t, scalemin, scalemax;
} ParticleRenderElem;

typedef struct ParticleRenderData {
    ChildParticle *child;
    ParticleCacheKey **pathcache;
    ParticleCacheKey **childcache;
    ListBase pathcachebufs, childcachebufs;
    int totchild, totcached, totchildcache;
    DerivedMesh *dm;
    int totdmvert, totdmedge, totdmface;

    float mat[4][4];
    float viewmat[4][4], winmat[4][4];
    int winx, winy;

    int dosimplify;
    int timeoffset;
    ParticleRenderElem *elems;
    int *origindex;
} ParticleRenderData;

static float psys_render_viewport_falloff(double rate, float dist, float width)
{
    return pow(rate, dist/width);
}

static float psys_render_projected_area(ParticleSystem *psys, const float center[3], float area, double vprate, float *viewport)
{
    ParticleRenderData *data= psys->renderdata;
    float co[4], view[3], ortho1[3], ortho2[3], w, dx, dy, radius;
    
    /* transform to view space */
    copy_v3_v3(co, center);
    co[3]= 1.0f;
    mul_m4_v4(data->viewmat, co);
    
    /* compute two vectors orthogonal to view vector */
    normalize_v3_v3(view, co);
    ortho_basis_v3v3_v3( ortho1, ortho2,view);

    /* compute on screen minification */
    w= co[2]*data->winmat[2][3] + data->winmat[3][3];
    dx= data->winx*ortho2[0]*data->winmat[0][0];
    dy= data->winy*ortho2[1]*data->winmat[1][1];
    w= sqrtf(dx*dx + dy*dy)/w;

    /* w squared because we are working with area */
    area= area*w*w;

    /* viewport of the screen test */

    /* project point on screen */
    mul_m4_v4(data->winmat, co);
    if(co[3] != 0.0f) {
        co[0]= 0.5f*data->winx*(1.0f + co[0]/co[3]);
        co[1]= 0.5f*data->winy*(1.0f + co[1]/co[3]);
    }

    /* screen space radius */
    radius= sqrt(area/(float)M_PI);

    /* make smaller using fallof once over screen edge */
    *viewport= 1.0f;

    if(co[0]+radius < 0.0f)
        *viewport *= psys_render_viewport_falloff(vprate, -(co[0]+radius), data->winx);
    else if(co[0]-radius > data->winx)
        *viewport *= psys_render_viewport_falloff(vprate, (co[0]-radius) - data->winx, data->winx);

    if(co[1]+radius < 0.0f)
        *viewport *= psys_render_viewport_falloff(vprate, -(co[1]+radius), data->winy);
    else if(co[1]-radius > data->winy)
        *viewport *= psys_render_viewport_falloff(vprate, (co[1]-radius) - data->winy, data->winy);
    
    return area;
}

void psys_render_set(Object *ob, ParticleSystem *psys, float viewmat[][4], float winmat[][4], int winx, int winy, int timeoffset)
{
    ParticleRenderData*data;
    ParticleSystemModifierData *psmd= psys_get_modifier(ob, psys);

    if(!G.rendering)
        return;
    if(psys->renderdata)
        return;

    data= MEM_callocN(sizeof(ParticleRenderData), "ParticleRenderData");

    data->child= psys->child;
    data->totchild= psys->totchild;
    data->pathcache= psys->pathcache;
    data->pathcachebufs.first = psys->pathcachebufs.first;
    data->pathcachebufs.last = psys->pathcachebufs.last;
    data->totcached= psys->totcached;
    data->childcache= psys->childcache;
    data->childcachebufs.first = psys->childcachebufs.first;
    data->childcachebufs.last = psys->childcachebufs.last;
    data->totchildcache= psys->totchildcache;

    if(psmd->dm)
        data->dm= CDDM_copy(psmd->dm);
    data->totdmvert= psmd->totdmvert;
    data->totdmedge= psmd->totdmedge;
    data->totdmface= psmd->totdmface;

    psys->child= NULL;
    psys->pathcache= NULL;
    psys->childcache= NULL;
    psys->totchild= psys->totcached= psys->totchildcache= 0;
    psys->pathcachebufs.first = psys->pathcachebufs.last = NULL;
    psys->childcachebufs.first = psys->childcachebufs.last = NULL;

    copy_m4_m4(data->winmat, winmat);
    mult_m4_m4m4(data->viewmat, viewmat, ob->obmat);
    mult_m4_m4m4(data->mat, winmat, data->viewmat);
    data->winx= winx;
    data->winy= winy;

    data->timeoffset= timeoffset;

    psys->renderdata= data;

    /* Hair can and has to be recalculated if everything isn't displayed. */
    if(psys->part->disp != 100 && psys->part->type == PART_HAIR)
        psys->recalc |= PSYS_RECALC_RESET;
}

void psys_render_restore(Object *ob, ParticleSystem *psys)
{
    ParticleRenderData*data;
    ParticleSystemModifierData *psmd= psys_get_modifier(ob, psys);

    data= psys->renderdata;
    if(!data)
        return;
    
    if(data->elems)
        MEM_freeN(data->elems);

    if(psmd->dm) {
        psmd->dm->needsFree= 1;
        psmd->dm->release(psmd->dm);
    }

    psys_free_path_cache(psys, NULL);

    if(psys->child){
        MEM_freeN(psys->child);
        psys->child= 0;
        psys->totchild= 0;
    }

    psys->child= data->child;
    psys->totchild= data->totchild;
    psys->pathcache= data->pathcache;
    psys->pathcachebufs.first = data->pathcachebufs.first;
    psys->pathcachebufs.last = data->pathcachebufs.last;
    psys->totcached= data->totcached;
    psys->childcache= data->childcache;
    psys->childcachebufs.first = data->childcachebufs.first;
    psys->childcachebufs.last = data->childcachebufs.last;
    psys->totchildcache= data->totchildcache;

    psmd->dm= data->dm;
    psmd->totdmvert= data->totdmvert;
    psmd->totdmedge= data->totdmedge;
    psmd->totdmface= data->totdmface;
    psmd->flag &= ~eParticleSystemFlag_psys_updated;

    if(psmd->dm)
        psys_calc_dmcache(ob, psmd->dm, psys);

    MEM_freeN(data);
    psys->renderdata= NULL;
}

int psys_render_simplify_distribution(ParticleThreadContext *ctx, int tot)
{
    DerivedMesh *dm= ctx->dm;
    Mesh *me= (Mesh*)(ctx->sim.ob->data);
    MFace *mf, *mface;
    MVert *mvert;
    ParticleRenderData *data;
    ParticleRenderElem *elems, *elem;
    ParticleSettings *part= ctx->sim.psys->part;
    float *facearea, (*facecenter)[3], size[3], fac, powrate, scaleclamp;
    float co1[3], co2[3], co3[3], co4[3], lambda, arearatio, t, area, viewport;
    double vprate;
    int *origindex, *facetotvert;
    int a, b, totorigface, totface, newtot, skipped;

    if(part->ren_as!=PART_DRAW_PATH || !(part->draw & PART_DRAW_REN_STRAND))
        return tot;
    if(!ctx->sim.psys->renderdata)
        return tot;

    data= ctx->sim.psys->renderdata;
    if(data->timeoffset)
        return 0;
    if(!(part->simplify_flag & PART_SIMPLIFY_ENABLE))
        return tot;

    mvert= dm->getVertArray(dm);
    mface= dm->getFaceArray(dm);
    origindex= dm->getFaceDataArray(dm, CD_ORIGINDEX);
    totface= dm->getNumFaces(dm);
    totorigface= me->totface;

    if(totface == 0 || totorigface == 0)
        return tot;

    facearea= MEM_callocN(sizeof(float)*totorigface, "SimplifyFaceArea");
    facecenter= MEM_callocN(sizeof(float[3])*totorigface, "SimplifyFaceCenter");
    facetotvert= MEM_callocN(sizeof(int)*totorigface, "SimplifyFaceArea");
    elems= MEM_callocN(sizeof(ParticleRenderElem)*totorigface, "SimplifyFaceElem");

    if(data->elems)
        MEM_freeN(data->elems);

    data->dosimplify= 1;
    data->elems= elems;
    data->origindex= origindex;

    /* compute number of children per original face */
    for(a=0; a<tot; a++) {
        b= (origindex)? origindex[ctx->index[a]]: ctx->index[a];
        if(b != -1)
            elems[b].totchild++;
    }

    /* compute areas and centers of original faces */
    for(mf=mface, a=0; a<totface; a++, mf++) {
        b= (origindex)? origindex[a]: a;

        if(b != -1) {
            copy_v3_v3(co1, mvert[mf->v1].co);
            copy_v3_v3(co2, mvert[mf->v2].co);
            copy_v3_v3(co3, mvert[mf->v3].co);

            add_v3_v3(facecenter[b], co1);
            add_v3_v3(facecenter[b], co2);
            add_v3_v3(facecenter[b], co3);

            if(mf->v4) {
                copy_v3_v3(co4, mvert[mf->v4].co);
                add_v3_v3(facecenter[b], co4);
                facearea[b] += area_quad_v3(co1, co2, co3, co4);
                facetotvert[b] += 4;
            }
            else {
                facearea[b] += area_tri_v3(co1, co2, co3);
                facetotvert[b] += 3;
            }
        }
    }

    for(a=0; a<totorigface; a++)
        if(facetotvert[a] > 0)
            mul_v3_fl(facecenter[a], 1.0f/facetotvert[a]);

    /* for conversion from BU area / pixel area to reference screen size */
    mesh_get_texspace(me, 0, 0, size);
    fac= ((size[0] + size[1] + size[2])/3.0f)/part->simplify_refsize;
    fac= fac*fac;

    powrate= log(0.5f)/log(part->simplify_rate*0.5f);
    if(part->simplify_flag & PART_SIMPLIFY_VIEWPORT)
        vprate= pow(1.0f - part->simplify_viewport, 5.0);
    else
        vprate= 1.0;

    /* set simplification parameters per original face */
    for(a=0, elem=elems; a<totorigface; a++, elem++) {
        area = psys_render_projected_area(ctx->sim.psys, facecenter[a], facearea[a], vprate, &viewport);
        arearatio= fac*area/facearea[a];

        if((arearatio < 1.0f || viewport < 1.0f) && elem->totchild) {
            /* lambda is percentage of elements to keep */
            lambda= (arearatio < 1.0f)? powf(arearatio, powrate): 1.0f;
            lambda *= viewport;

            lambda= MAX2(lambda, 1.0f/elem->totchild);

            /* compute transition region */
            t= part->simplify_transition;
            elem->t= (lambda-t < 0.0f)? lambda: (lambda+t > 1.0f)? 1.0f-lambda: t;
            elem->reduce= 1;

            /* scale at end and beginning of the transition region */
            elem->scalemax= (lambda+t < 1.0f)? 1.0f/lambda: 1.0f/(1.0f - elem->t*elem->t/t);
            elem->scalemin= (lambda+t < 1.0f)? 0.0f: elem->scalemax*(1.0f-elem->t/t);

            elem->scalemin= sqrt(elem->scalemin);
            elem->scalemax= sqrt(elem->scalemax);

            /* clamp scaling */
            scaleclamp= MIN2(elem->totchild, 10.0f);
            elem->scalemin= MIN2(scaleclamp, elem->scalemin);
            elem->scalemax= MIN2(scaleclamp, elem->scalemax);

            /* extend lambda to include transition */
            lambda= lambda + elem->t;
            if(lambda > 1.0f)
                lambda= 1.0f;
        }
        else {
            lambda= arearatio;

            elem->scalemax= 1.0f; //sqrt(lambda);
            elem->scalemin= 1.0f; //sqrt(lambda);
            elem->reduce= 0;
        }

        elem->lambda= lambda;
        elem->scalemin= sqrt(elem->scalemin);
        elem->scalemax= sqrt(elem->scalemax);
        elem->curchild= 0;
    }

    MEM_freeN(facearea);
    MEM_freeN(facecenter);
    MEM_freeN(facetotvert);

    /* move indices and set random number skipping */
    ctx->skip= MEM_callocN(sizeof(int)*tot, "SimplificationSkip");

    skipped= 0;
    for(a=0, newtot=0; a<tot; a++) {
        b= (origindex)? origindex[ctx->index[a]]: ctx->index[a];
        if(b != -1) {
            if(elems[b].curchild++ < ceil(elems[b].lambda*elems[b].totchild)) {
                ctx->index[newtot]= ctx->index[a];
                ctx->skip[newtot]= skipped;
                skipped= 0;
                newtot++;
            }
            else skipped++;
        }
        else skipped++;
    }

    for(a=0, elem=elems; a<totorigface; a++, elem++)
        elem->curchild= 0;

    return newtot;
}

int psys_render_simplify_params(ParticleSystem *psys, ChildParticle *cpa, float *params)
{
    ParticleRenderData *data;
    ParticleRenderElem *elem;
    float x, w, scale, alpha, lambda, t, scalemin, scalemax;
    int b;

    if(!(psys->renderdata && (psys->part->simplify_flag & PART_SIMPLIFY_ENABLE)))
        return 0;
    
    data= psys->renderdata;
    if(!data->dosimplify)
        return 0;
    
    b= (data->origindex)? data->origindex[cpa->num]: cpa->num;
    if(b == -1)
        return 0;

    elem= &data->elems[b];

    lambda= elem->lambda;
    t= elem->t;
    scalemin= elem->scalemin;
    scalemax= elem->scalemax;

    if(!elem->reduce) {
        scale= scalemin;
        alpha= 1.0f;
    }
    else {
        x= (elem->curchild+0.5f)/elem->totchild;
        if(x < lambda-t) {
            scale= scalemax;
            alpha= 1.0f;
        }
        else if(x >= lambda+t) {
            scale= scalemin;
            alpha= 0.0f;
        }
        else {
            w= (lambda+t - x)/(2.0f*t);
            scale= scalemin + (scalemax - scalemin)*w;
            alpha= w;
        }
    }

    params[0]= scale;
    params[1]= alpha;

    elem->curchild++;

    return 1;
}

/************************************************/
/*          Interpolation                       */
/************************************************/
static float interpolate_particle_value(float v1, float v2, float v3, float v4, const float w[4], int four)
{
    float value;

    value= w[0]*v1 + w[1]*v2 + w[2]*v3;
    if(four)
        value += w[3]*v4;

    CLAMP(value, 0.f, 1.f);
    
    return value;
}

void psys_interpolate_particle(short type, ParticleKey keys[4], float dt, ParticleKey *result, int velocity)
{
    float t[4];

    if(type<0) {
        interp_cubic_v3( result->co, result->vel,keys[1].co, keys[1].vel, keys[2].co, keys[2].vel, dt);
    }
    else {
        key_curve_position_weights(dt, t, type);

        interp_v3_v3v3v3v3(result->co, keys[0].co, keys[1].co, keys[2].co, keys[3].co, t);

        if(velocity){
            float temp[3];

            if(dt>0.999f){
                key_curve_position_weights(dt-0.001f, t, type);
                interp_v3_v3v3v3v3(temp, keys[0].co, keys[1].co, keys[2].co, keys[3].co, t);
                sub_v3_v3v3(result->vel, result->co, temp);
            }
            else{
                key_curve_position_weights(dt+0.001f, t, type);
                interp_v3_v3v3v3v3(temp, keys[0].co, keys[1].co, keys[2].co, keys[3].co, t);
                sub_v3_v3v3(result->vel, temp, result->co);
            }
        }
    }
}



typedef struct ParticleInterpolationData {
    HairKey *hkey[2];

    DerivedMesh *dm;
    MVert *mvert[2];

    int keyed;
    ParticleKey *kkey[2];

    PointCache *cache;
    PTCacheMem *pm;

    PTCacheEditPoint *epoint;
    PTCacheEditKey *ekey[2];

    float birthtime, dietime;
    int bspline;
} ParticleInterpolationData;
/* Assumes pointcache->mem_cache exists, so for disk cached particles call psys_make_temp_pointcache() before use */
/* It uses ParticleInterpolationData->pm to store the current memory cache frame so it's thread safe. */
static void get_pointcache_keys_for_time(Object *UNUSED(ob), PointCache *cache, PTCacheMem **cur, int index, float t, ParticleKey *key1, ParticleKey *key2)
{
    static PTCacheMem *pm = NULL;
    int index1, index2;

    if(index < 0) { /* initialize */
        *cur = cache->mem_cache.first;

        if(*cur)
            *cur = (*cur)->next;
    }
    else {
        if(*cur) {
            while(*cur && (*cur)->next && (float)(*cur)->frame < t)
                *cur = (*cur)->next;

            pm = *cur;

            index2 = BKE_ptcache_mem_index_find(pm, index);
            index1 = BKE_ptcache_mem_index_find(pm->prev, index);

            BKE_ptcache_make_particle_key(key2, index2, pm->data, (float)pm->frame);
            if(index1 < 0)
                copy_particle_key(key1, key2, 1);
            else
                BKE_ptcache_make_particle_key(key1, index1, pm->prev->data, (float)pm->prev->frame);
        }
        else if(cache->mem_cache.first) {
            pm = cache->mem_cache.first;
            index2 = BKE_ptcache_mem_index_find(pm, index);
            BKE_ptcache_make_particle_key(key2, index2, pm->data, (float)pm->frame);
            copy_particle_key(key1, key2, 1);
        }
    }
}
static int get_pointcache_times_for_particle(PointCache *cache, int index, float *start, float *end)
{
    PTCacheMem *pm;
    int ret = 0;

    for(pm=cache->mem_cache.first; pm; pm=pm->next) {
        if(BKE_ptcache_mem_index_find(pm, index) >= 0) {
            *start = pm->frame;
            ret++;
            break;
        }
    }

    for(pm=cache->mem_cache.last; pm; pm=pm->prev) {
        if(BKE_ptcache_mem_index_find(pm, index) >= 0) {
            *end = pm->frame;
            ret++;
            break;
        }
    }

    return ret == 2;
}

float psys_get_dietime_from_cache(PointCache *cache, int index)
{
    PTCacheMem *pm;
    int dietime = 10000000; /* some max value so that we can default to pa->time+lifetime */

    for(pm=cache->mem_cache.last; pm; pm=pm->prev) {
        if(BKE_ptcache_mem_index_find(pm, index) >= 0)
            return (float)pm->frame;
    }

    return (float)dietime;
}

static void init_particle_interpolation(Object *ob, ParticleSystem *psys, ParticleData *pa, ParticleInterpolationData *pind)
{

    if(pind->epoint) {
        PTCacheEditPoint *point = pind->epoint;

        pind->ekey[0] = point->keys;
        pind->ekey[1] = point->totkey > 1 ? point->keys + 1 : NULL;

        pind->birthtime = *(point->keys->time);
        pind->dietime = *((point->keys + point->totkey - 1)->time);
    }
    else if(pind->keyed) {
        ParticleKey *key = pa->keys;
        pind->kkey[0] = key;
        pind->kkey[1] = pa->totkey > 1 ? key + 1 : NULL;

        pind->birthtime = key->time;
        pind->dietime = (key + pa->totkey - 1)->time;
    }
    else if(pind->cache) {
        float start=0.0f, end=0.0f;
        get_pointcache_keys_for_time(ob, pind->cache, &pind->pm, -1, 0.0f, NULL, NULL);
        pind->birthtime = pa ? pa->time : pind->cache->startframe;
        pind->dietime = pa ? pa->dietime : pind->cache->endframe;

        if(get_pointcache_times_for_particle(pind->cache, pa - psys->particles, &start, &end)) {
            pind->birthtime = MAX2(pind->birthtime, start);
            pind->dietime = MIN2(pind->dietime, end);
        }
    }
    else {
        HairKey *key = pa->hair;
        pind->hkey[0] = key;
        pind->hkey[1] = key + 1;

        pind->birthtime = key->time;
        pind->dietime = (key + pa->totkey - 1)->time;

        if(pind->dm) {
            pind->mvert[0] = CDDM_get_vert(pind->dm, pa->hair_index);
            pind->mvert[1] = pind->mvert[0] + 1;
        }
    }
}
static void edit_to_particle(ParticleKey *key, PTCacheEditKey *ekey)
{
    copy_v3_v3(key->co, ekey->co);
    if(ekey->vel) {
        copy_v3_v3(key->vel, ekey->vel);
    }
    key->time = *(ekey->time);
}
static void hair_to_particle(ParticleKey *key, HairKey *hkey)
{
    copy_v3_v3(key->co, hkey->co);
    key->time = hkey->time;
}

static void mvert_to_particle(ParticleKey *key, MVert *mvert, HairKey *hkey)
{
    copy_v3_v3(key->co, mvert->co);
    key->time = hkey->time;
}

static void do_particle_interpolation(ParticleSystem *psys, int p, ParticleData *pa, float t, ParticleInterpolationData *pind, ParticleKey *result)
{
    PTCacheEditPoint *point = pind->epoint;
    ParticleKey keys[4];
    int point_vel = (point && point->keys->vel);
    float real_t, dfra, keytime, invdt = 1.f;

    /* billboards wont fill in all of these, so start cleared */
    memset(keys, 0, sizeof(keys));

    /* interpret timing and find keys */
    if(point) {
        if(result->time < 0.0f)
            real_t = -result->time;
        else
            real_t = *(pind->ekey[0]->time) + t * (*(pind->ekey[0][point->totkey-1].time) - *(pind->ekey[0]->time));

        while(*(pind->ekey[1]->time) < real_t)
            pind->ekey[1]++;

        pind->ekey[0] = pind->ekey[1] - 1;
    }
    else if(pind->keyed) {
        /* we have only one key, so let's use that */
        if(pind->kkey[1]==NULL) {
            copy_particle_key(result, pind->kkey[0], 1);
            return;
        }

        if(result->time < 0.0f)
            real_t = -result->time;
        else
            real_t = pind->kkey[0]->time + t * (pind->kkey[0][pa->totkey-1].time - pind->kkey[0]->time);

        if(psys->part->phystype==PART_PHYS_KEYED && psys->flag & PSYS_KEYED_TIMING) {
            ParticleTarget *pt = psys->targets.first;

            pt=pt->next;

            while(pt && pa->time + pt->time < real_t)
                pt= pt->next;

            if(pt) {
                pt=pt->prev;

                if(pa->time + pt->time + pt->duration > real_t)
                    real_t = pa->time + pt->time;
            }
            else
                real_t = pa->time + ((ParticleTarget*)psys->targets.last)->time;
        }

        CLAMP(real_t, pa->time, pa->dietime);

        while(pind->kkey[1]->time < real_t)
            pind->kkey[1]++;
        
        pind->kkey[0] = pind->kkey[1] - 1;
    }
    else if(pind->cache) {
        if(result->time < 0.0f) /* flag for time in frames */
            real_t = -result->time;
        else
            real_t = pa->time + t * (pa->dietime - pa->time);
    }
    else {
        if(result->time < 0.0f)
            real_t = -result->time;
        else
            real_t = pind->hkey[0]->time + t * (pind->hkey[0][pa->totkey-1].time - pind->hkey[0]->time);

        while(pind->hkey[1]->time < real_t) {
            pind->hkey[1]++;
            pind->mvert[1]++;
        }

        pind->hkey[0] = pind->hkey[1] - 1;
    }

    /* set actual interpolation keys */
    if(point) {
        edit_to_particle(keys + 1, pind->ekey[0]);
        edit_to_particle(keys + 2, pind->ekey[1]);
    }
    else if(pind->dm) {
        pind->mvert[0] = pind->mvert[1] - 1;
        mvert_to_particle(keys + 1, pind->mvert[0], pind->hkey[0]);
        mvert_to_particle(keys + 2, pind->mvert[1], pind->hkey[1]);
    }
    else if(pind->keyed) {
        memcpy(keys + 1, pind->kkey[0], sizeof(ParticleKey));
        memcpy(keys + 2, pind->kkey[1], sizeof(ParticleKey));
    }
    else if(pind->cache) {
        get_pointcache_keys_for_time(NULL, pind->cache, &pind->pm, p, real_t, keys+1, keys+2);
    }
    else {
        hair_to_particle(keys + 1, pind->hkey[0]);
        hair_to_particle(keys + 2, pind->hkey[1]);
    }

    /* set secondary interpolation keys for hair */
    if(!pind->keyed && !pind->cache && !point_vel) {
        if(point) {
            if(pind->ekey[0] != point->keys)
                edit_to_particle(keys, pind->ekey[0] - 1);
            else
                edit_to_particle(keys, pind->ekey[0]);
        }
        else if(pind->dm) {
            if(pind->hkey[0] != pa->hair)
                mvert_to_particle(keys, pind->mvert[0] - 1, pind->hkey[0] - 1);
            else
                mvert_to_particle(keys, pind->mvert[0], pind->hkey[0]);
        }
        else {
            if(pind->hkey[0] != pa->hair)
                hair_to_particle(keys, pind->hkey[0] - 1);
            else
                hair_to_particle(keys, pind->hkey[0]);
        }

        if(point) {
            if(pind->ekey[1] != point->keys + point->totkey - 1)
                edit_to_particle(keys + 3, pind->ekey[1] + 1);
            else
                edit_to_particle(keys + 3, pind->ekey[1]);
        }
        else if(pind->dm) {
            if(pind->hkey[1] != pa->hair + pa->totkey - 1)
                mvert_to_particle(keys + 3, pind->mvert[1] + 1, pind->hkey[1] + 1);
            else
                mvert_to_particle(keys + 3, pind->mvert[1], pind->hkey[1]);
        }
        else {
            if(pind->hkey[1] != pa->hair + pa->totkey - 1)
                hair_to_particle(keys + 3, pind->hkey[1] + 1);
            else
                hair_to_particle(keys + 3, pind->hkey[1]);
        }
    }

    dfra = keys[2].time - keys[1].time;
    keytime = (real_t - keys[1].time) / dfra;

    /* convert velocity to timestep size */
    if(pind->keyed || pind->cache || point_vel){
        invdt = dfra * 0.04f * (psys ? psys->part->timetweak : 1.f);
        mul_v3_fl(keys[1].vel, invdt);
        mul_v3_fl(keys[2].vel, invdt);
        interp_qt_qtqt(result->rot,keys[1].rot,keys[2].rot,keytime);
    }

    /* now we should have in chronologiacl order k1<=k2<=t<=k3<=k4 with keytime between [0,1]->[k2,k3] (k1 & k4 used for cardinal & bspline interpolation)*/
    psys_interpolate_particle((pind->keyed || pind->cache || point_vel) ? -1 /* signal for cubic interpolation */
        : (pind->bspline ? KEY_BSPLINE : KEY_CARDINAL)
        ,keys, keytime, result, 1);

    /* the velocity needs to be converted back from cubic interpolation */
    if(pind->keyed || pind->cache || point_vel)
        mul_v3_fl(result->vel, 1.f/invdt);
}
/************************************************/
/*          Particles on a dm                   */
/************************************************/
/* interpolate a location on a face based on face coordinates */
void psys_interpolate_face(MVert *mvert, MFace *mface, MTFace *tface, float (*orcodata)[3],
                           float *w, float *vec, float *nor, float *utan, float *vtan, float *orco,float *ornor)
{
    float *v1=0, *v2=0, *v3=0, *v4=0;
    float e1[3],e2[3],s1,s2,t1,t2;
    float *uv1, *uv2, *uv3, *uv4;
    float n1[3], n2[3], n3[3], n4[3];
    float tuv[4][2];
    float *o1, *o2, *o3, *o4;

    v1= mvert[mface->v1].co;
    v2= mvert[mface->v2].co;
    v3= mvert[mface->v3].co;

    normal_short_to_float_v3(n1, mvert[mface->v1].no);
    normal_short_to_float_v3(n2, mvert[mface->v2].no);
    normal_short_to_float_v3(n3, mvert[mface->v3].no);

    if(mface->v4) {
        v4= mvert[mface->v4].co;
        normal_short_to_float_v3(n4, mvert[mface->v4].no);
        
        interp_v3_v3v3v3v3(vec, v1, v2, v3, v4, w);

        if(nor){
            if(mface->flag & ME_SMOOTH)
                interp_v3_v3v3v3v3(nor, n1, n2, n3, n4, w);
            else
                normal_quad_v3(nor,v1,v2,v3,v4);
        }
    }
    else {
        interp_v3_v3v3v3(vec, v1, v2, v3, w);

        if(nor){
            if(mface->flag & ME_SMOOTH)
                interp_v3_v3v3v3(nor, n1, n2, n3, w);
            else
                normal_tri_v3(nor,v1,v2,v3);
        }
    }
    
    /* calculate tangent vectors */
    if(utan && vtan){
        if(tface){
            uv1= tface->uv[0];
            uv2= tface->uv[1];
            uv3= tface->uv[2];
            uv4= tface->uv[3];
        }
        else{
            uv1= tuv[0]; uv2= tuv[1]; uv3= tuv[2]; uv4= tuv[3];
            map_to_sphere( uv1, uv1+1,v1[0], v1[1], v1[2]);
            map_to_sphere( uv2, uv2+1,v2[0], v2[1], v2[2]);
            map_to_sphere( uv3, uv3+1,v3[0], v3[1], v3[2]);
            if(v4)
                map_to_sphere( uv4, uv4+1,v4[0], v4[1], v4[2]);
        }

        if(v4){
            s1= uv3[0] - uv1[0];
            s2= uv4[0] - uv1[0];

            t1= uv3[1] - uv1[1];
            t2= uv4[1] - uv1[1];

            sub_v3_v3v3(e1, v3, v1);
            sub_v3_v3v3(e2, v4, v1);
        }
        else{
            s1= uv2[0] - uv1[0];
            s2= uv3[0] - uv1[0];

            t1= uv2[1] - uv1[1];
            t2= uv3[1] - uv1[1];

            sub_v3_v3v3(e1, v2, v1);
            sub_v3_v3v3(e2, v3, v1);
        }

        vtan[0] = (s1*e2[0] - s2*e1[0]);
        vtan[1] = (s1*e2[1] - s2*e1[1]);
        vtan[2] = (s1*e2[2] - s2*e1[2]);

        utan[0] = (t1*e2[0] - t2*e1[0]);
        utan[1] = (t1*e2[1] - t2*e1[1]);
        utan[2] = (t1*e2[2] - t2*e1[2]);
    }

    if(orco) {
        if(orcodata) {
            o1= orcodata[mface->v1];
            o2= orcodata[mface->v2];
            o3= orcodata[mface->v3];

            if(mface->v4) {
                o4= orcodata[mface->v4];

                interp_v3_v3v3v3v3(orco, o1, o2, o3, o4, w);

                if(ornor)
                    normal_quad_v3( ornor,o1, o2, o3, o4);
            }
            else {
                interp_v3_v3v3v3(orco, o1, o2, o3, w);

                if(ornor)
                    normal_tri_v3( ornor,o1, o2, o3);
            }
        }
        else {
            copy_v3_v3(orco, vec);
            if(ornor && nor)
                copy_v3_v3(ornor, nor);
        }
    }
}
void psys_interpolate_uvs(const MTFace *tface, int quad, const float w[4], float uvco[2])
{
    float v10= tface->uv[0][0];
    float v11= tface->uv[0][1];
    float v20= tface->uv[1][0];
    float v21= tface->uv[1][1];
    float v30= tface->uv[2][0];
    float v31= tface->uv[2][1];
    float v40,v41;

    if(quad) {
        v40= tface->uv[3][0];
        v41= tface->uv[3][1];

        uvco[0]= w[0]*v10 + w[1]*v20 + w[2]*v30 + w[3]*v40;
        uvco[1]= w[0]*v11 + w[1]*v21 + w[2]*v31 + w[3]*v41;
    }
    else {
        uvco[0]= w[0]*v10 + w[1]*v20 + w[2]*v30;
        uvco[1]= w[0]*v11 + w[1]*v21 + w[2]*v31;
    }
}

void psys_interpolate_mcol(const MCol *mcol, int quad, const float w[4], MCol *mc)
{
    char *cp, *cp1, *cp2, *cp3, *cp4;

    cp= (char *)mc;
    cp1= (char *)&mcol[0];
    cp2= (char *)&mcol[1];
    cp3= (char *)&mcol[2];
    
    if(quad) {
        cp4= (char *)&mcol[3];

        cp[0]= (int)(w[0]*cp1[0] + w[1]*cp2[0] + w[2]*cp3[0] + w[3]*cp4[0]);
        cp[1]= (int)(w[0]*cp1[1] + w[1]*cp2[1] + w[2]*cp3[1] + w[3]*cp4[1]);
        cp[2]= (int)(w[0]*cp1[2] + w[1]*cp2[2] + w[2]*cp3[2] + w[3]*cp4[2]);
        cp[3]= (int)(w[0]*cp1[3] + w[1]*cp2[3] + w[2]*cp3[3] + w[3]*cp4[3]);
    }
    else {
        cp[0]= (int)(w[0]*cp1[0] + w[1]*cp2[0] + w[2]*cp3[0]);
        cp[1]= (int)(w[0]*cp1[1] + w[1]*cp2[1] + w[2]*cp3[1]);
        cp[2]= (int)(w[0]*cp1[2] + w[1]*cp2[2] + w[2]*cp3[2]);
        cp[3]= (int)(w[0]*cp1[3] + w[1]*cp2[3] + w[2]*cp3[3]);
    }
}

static float psys_interpolate_value_from_verts(DerivedMesh *dm, short from, int index, const float fw[4], const float *values)
{
    if(values==0 || index==-1)
        return 0.0;

    switch(from){
        case PART_FROM_VERT:
            return values[index];
        case PART_FROM_FACE:
        case PART_FROM_VOLUME:
        {
            MFace *mf=dm->getFaceData(dm,index,CD_MFACE);
            return interpolate_particle_value(values[mf->v1],values[mf->v2],values[mf->v3],values[mf->v4],fw,mf->v4);
        }
            
    }
    return 0.0f;
}

/* conversion of pa->fw to origspace layer coordinates */
static void psys_w_to_origspace(const float w[4], float uv[2])
{
    uv[0]= w[1] + w[2];
    uv[1]= w[2] + w[3];
}

/* conversion of pa->fw to weights in face from origspace */
static void psys_origspace_to_w(OrigSpaceFace *osface, int quad, const float w[4], float neww[4])
{
    float v[4][3], co[3];

    v[0][0]= osface->uv[0][0]; v[0][1]= osface->uv[0][1]; v[0][2]= 0.0f;
    v[1][0]= osface->uv[1][0]; v[1][1]= osface->uv[1][1]; v[1][2]= 0.0f;
    v[2][0]= osface->uv[2][0]; v[2][1]= osface->uv[2][1]; v[2][2]= 0.0f;

    psys_w_to_origspace(w, co);
    co[2]= 0.0f;
    
    if(quad) {
        v[3][0]= osface->uv[3][0]; v[3][1]= osface->uv[3][1]; v[3][2]= 0.0f;
        interp_weights_poly_v3(neww, v, 4, co);
    }
    else {
        interp_weights_poly_v3(neww, v, 3, co);
        neww[3]= 0.0f;
    }
}

/* find the derived mesh face for a particle, set the mf passed. this is slow
 * and can be optimized but only for many lookups. returns the face index. */
int psys_particle_dm_face_lookup(Object *ob, DerivedMesh *dm, int index, const float fw[4], struct LinkNode *node)
{
    Mesh *me= (Mesh*)ob->data;
    MFace *mface;
    OrigSpaceFace *osface;
    int *origindex;
    int quad, findex, totface;
    float uv[2], (*faceuv)[2];

    mface = dm->getFaceDataArray(dm, CD_MFACE);
    origindex = dm->getFaceDataArray(dm, CD_ORIGINDEX);
    osface = dm->getFaceDataArray(dm, CD_ORIGSPACE);

    totface = dm->getNumFaces(dm);
    
    if(osface==NULL || origindex==NULL) {
        /* Assume we dont need osface data */
        if (index <totface) {
            //printf("\tNO CD_ORIGSPACE, assuming not needed\n");
            return index;
        } else {
            printf("\tNO CD_ORIGSPACE, error out of range\n");
            return DMCACHE_NOTFOUND;
        }
    }
    else if(index >= me->totface)
        return DMCACHE_NOTFOUND; /* index not in the original mesh */

    psys_w_to_origspace(fw, uv);
    
    if(node) { /* we have a linked list of faces that we use, faster! */
        for(;node; node=node->next) {
            findex= GET_INT_FROM_POINTER(node->link);
            faceuv= osface[findex].uv;
            quad= mface[findex].v4;

            /* check that this intersects - Its possible this misses :/ -
             * could also check its not between */
            if(quad) {
                if(isect_point_quad_v2(uv, faceuv[0], faceuv[1], faceuv[2], faceuv[3]))
                    return findex;
            }
            else if(isect_point_tri_v2(uv, faceuv[0], faceuv[1], faceuv[2]))
                return findex;
        }
    }
    else { /* if we have no node, try every face */
        for(findex=0; findex<totface; findex++) {
            if(origindex[findex] == index) {
                faceuv= osface[findex].uv;
                quad= mface[findex].v4;

                /* check that this intersects - Its possible this misses :/ -
                 * could also check its not between */
                if(quad) {
                    if(isect_point_quad_v2(uv, faceuv[0], faceuv[1], faceuv[2], faceuv[3]))
                        return findex;
                }
                else if(isect_point_tri_v2(uv, faceuv[0], faceuv[1], faceuv[2]))
                    return findex;
            }
        }
    }

    return DMCACHE_NOTFOUND;
}

static int psys_map_index_on_dm(DerivedMesh *dm, int from, int index, int index_dmcache, const float fw[4], float UNUSED(foffset), int *mapindex, float mapfw[4])
{
    if(index < 0)
        return 0;

    if (dm->deformedOnly || index_dmcache == DMCACHE_ISCHILD) {
        /* for meshes that are either only defined or for child particles, the
         * index and fw do not require any mapping, so we can directly use it */
        if(from == PART_FROM_VERT) {
            if(index >= dm->getNumVerts(dm))
                return 0;

            *mapindex = index;
        }
        else  { /* FROM_FACE/FROM_VOLUME */
            if(index >= dm->getNumFaces(dm))
                return 0;

            *mapindex = index;
            copy_v4_v4(mapfw, fw);
        }
    } else {
        /* for other meshes that have been modified, we try to map the particle
         * to their new location, which means a different index, and for faces
         * also a new face interpolation weights */
        if(from == PART_FROM_VERT) {
            if (index_dmcache == DMCACHE_NOTFOUND || index_dmcache > dm->getNumVerts(dm))
                return 0;

            *mapindex = index_dmcache;
        }
        else  { /* FROM_FACE/FROM_VOLUME */
            /* find a face on the derived mesh that uses this face */
            MFace *mface;
            OrigSpaceFace *osface;
            int i;

            i = index_dmcache;

            if(i== DMCACHE_NOTFOUND || i >= dm->getNumFaces(dm))
                return 0;

            *mapindex = i;

            /* modify the original weights to become
             * weights for the derived mesh face */
            osface= dm->getFaceDataArray(dm, CD_ORIGSPACE);
            mface= dm->getFaceData(dm, i, CD_MFACE);

            if(osface == NULL)
                mapfw[0]= mapfw[1]= mapfw[2]= mapfw[3]= 0.0f;
            else
                psys_origspace_to_w(&osface[i], mface->v4, fw, mapfw);
        }
    }

    return 1;
}

/* interprets particle data to get a point on a mesh in object space */
void psys_particle_on_dm(DerivedMesh *dm, int from, int index, int index_dmcache, const float fw[4], float foffset, float vec[3], float nor[3], float utan[3], float vtan[3], float orco[3], float ornor[3])
{
    float tmpnor[3], mapfw[4];
    float (*orcodata)[3];
    int mapindex;

    if(!psys_map_index_on_dm(dm, from, index, index_dmcache, fw, foffset, &mapindex, mapfw)) {
        if(vec) { vec[0]=vec[1]=vec[2]=0.0; }
        if(nor) { nor[0]=nor[1]=0.0; nor[2]=1.0; }
        if(orco) { orco[0]=orco[1]=orco[2]=0.0; }
        if(ornor) { ornor[0]=ornor[1]=0.0; ornor[2]=1.0; }
        if(utan) { utan[0]=utan[1]=utan[2]=0.0; }
        if(vtan) { vtan[0]=vtan[1]=vtan[2]=0.0; }

        return;
    }

    orcodata= dm->getVertDataArray(dm, CD_ORCO);

    if(from == PART_FROM_VERT) {
        dm->getVertCo(dm,mapindex,vec);

        if(nor) {
            dm->getVertNo(dm,mapindex,nor);
            normalize_v3(nor);
        }

        if(orco)
            copy_v3_v3(orco, orcodata[mapindex]);

        if(ornor) {
            dm->getVertNo(dm,mapindex,nor);
            normalize_v3(nor);
        }

        if(utan && vtan) {
            utan[0]= utan[1]= utan[2]= 0.0f;
            vtan[0]= vtan[1]= vtan[2]= 0.0f;
        }
    }
    else { /* PART_FROM_FACE / PART_FROM_VOLUME */
        MFace *mface;
        MTFace *mtface;
        MVert *mvert;

        mface=dm->getFaceData(dm,mapindex,CD_MFACE);
        mvert=dm->getVertDataArray(dm,CD_MVERT);
        mtface=CustomData_get_layer(&dm->faceData,CD_MTFACE);

        if(mtface)
            mtface += mapindex;

        if(from==PART_FROM_VOLUME) {
            psys_interpolate_face(mvert,mface,mtface,orcodata,mapfw,vec,tmpnor,utan,vtan,orco,ornor);
            if(nor)
                copy_v3_v3(nor,tmpnor);

            normalize_v3(tmpnor);
            mul_v3_fl(tmpnor,-foffset);
            add_v3_v3(vec, tmpnor);
        }
        else
            psys_interpolate_face(mvert,mface,mtface,orcodata,mapfw,vec,nor,utan,vtan,orco,ornor);
    }
}

float psys_particle_value_from_verts(DerivedMesh *dm, short from, ParticleData *pa, float *values)
{
    float mapfw[4];
    int mapindex;

    if(!psys_map_index_on_dm(dm, from, pa->num, pa->num_dmcache, pa->fuv, pa->foffset, &mapindex, mapfw))
        return 0.0f;
    
    return psys_interpolate_value_from_verts(dm, from, mapindex, mapfw, values);
}

ParticleSystemModifierData *psys_get_modifier(Object *ob, ParticleSystem *psys)
{
    ModifierData *md;
    ParticleSystemModifierData *psmd;

    for(md=ob->modifiers.first; md; md=md->next){
        if(md->type==eModifierType_ParticleSystem){
            psmd= (ParticleSystemModifierData*) md;
            if(psmd->psys==psys){
                return psmd;
            }
        }
    }
    return NULL;
}
/************************************************/
/*          Particles on a shape                */
/************************************************/
/* ready for future use */
static void psys_particle_on_shape(int UNUSED(distr), int UNUSED(index), float *UNUSED(fuv), float *vec, float *nor, float *utan, float *vtan, float *orco, float *ornor)
{
    /* TODO */
    float zerovec[3]={0.0f,0.0f,0.0f};
    if(vec){
        copy_v3_v3(vec,zerovec);
    }
    if(nor){
        copy_v3_v3(nor,zerovec);
    }
    if(utan){
        copy_v3_v3(utan,zerovec);
    }
    if(vtan){
        copy_v3_v3(vtan,zerovec);
    }
    if(orco){
        copy_v3_v3(orco,zerovec);
    }
    if(ornor){
        copy_v3_v3(ornor,zerovec);
    }
}
/************************************************/
/*          Particles on emitter                */
/************************************************/
void psys_particle_on_emitter(ParticleSystemModifierData *psmd, int from, int index, int index_dmcache, float *fuv, float foffset, float *vec, float *nor, float *utan, float *vtan, float *orco, float *ornor)
{
    if(psmd){
        if(psmd->psys->part->distr==PART_DISTR_GRID && psmd->psys->part->from != PART_FROM_VERT){
            if(vec)
                copy_v3_v3(vec,fuv);

            if(orco)
                copy_v3_v3(orco, fuv);
            return;
        }
        /* we cant use the num_dmcache */
        psys_particle_on_dm(psmd->dm,from,index,index_dmcache,fuv,foffset,vec,nor,utan,vtan,orco,ornor);
    }
    else
        psys_particle_on_shape(from,index,fuv,vec,nor,utan,vtan,orco,ornor);

}
/************************************************/
/*          Path Cache                          */
/************************************************/

static void do_kink(ParticleKey *state, ParticleKey *par, float *par_rot, float time, float freq, float shape, float amplitude, float flat, short type, short axis, float obmat[][4], int smooth_start)
{
    float kink[3]={1.f,0.f,0.f}, par_vec[3], q1[4]={1.f,0.f,0.f,0.f};
    float t, dt=1.f, result[3];

    if(par == NULL || type == PART_KINK_NO)
        return;

    CLAMP(time, 0.f, 1.f);

    if(shape!=0.0f && type!=PART_KINK_BRAID) {
        if(shape<0.0f)
            time= (float)pow(time, 1.f+shape);
        else
            time= (float)pow(time, 1.f/(1.f-shape));
    }

    t = time * freq *(float)M_PI;
    
    if(smooth_start) {
        dt = fabs(t);
        /* smooth the beginning of kink */
        CLAMP(dt, 0.f, (float)M_PI);
        dt = sin(dt/2.f);
    }

    if(type != PART_KINK_RADIAL) {
        float temp[3];

        kink[axis]=1.f;

        if(obmat)
            mul_mat3_m4_v3(obmat, kink);
        
        if(par_rot)
            mul_qt_v3(par_rot, kink);

        /* make sure kink is normal to strand */
        project_v3_v3v3(temp, kink, par->vel);
        sub_v3_v3(kink, temp);
        normalize_v3(kink);
    }

    copy_v3_v3(result, state->co);
    sub_v3_v3v3(par_vec, par->co, state->co);

    switch(type) {
    case PART_KINK_CURL:
    {
        negate_v3(par_vec);

        if(flat > 0.f) {
            float proj[3];
            project_v3_v3v3(proj, par_vec, par->vel);
            madd_v3_v3fl(par_vec, proj, -flat);

            project_v3_v3v3(proj, par_vec, kink);
            madd_v3_v3fl(par_vec, proj, -flat);
        }

        axis_angle_to_quat(q1, kink, (float)M_PI/2.f);

        mul_qt_v3(q1, par_vec);

        madd_v3_v3fl(par_vec, kink, amplitude);

        /* rotate kink vector around strand tangent */
        if(t!=0.f) {
            axis_angle_to_quat(q1, par->vel, t);
            mul_qt_v3(q1, par_vec);
        }

        add_v3_v3v3(result, par->co, par_vec);
        break;
    }
    case PART_KINK_RADIAL:
    {
        if(flat > 0.f) {
            float proj[3];
            /* flatten along strand */
            project_v3_v3v3(proj, par_vec, par->vel);
            madd_v3_v3fl(result, proj, flat);
        }

        madd_v3_v3fl(result, par_vec, -amplitude*(float)sin(t));
        break;
    }
    case PART_KINK_WAVE:
    {
        madd_v3_v3fl(result, kink, amplitude*(float)sin(t));

        if(flat > 0.f) {
            float proj[3];
            /* flatten along wave */
            project_v3_v3v3(proj, par_vec, kink);
            madd_v3_v3fl(result, proj, flat);

            /* flatten along strand */
            project_v3_v3v3(proj, par_vec, par->vel);
            madd_v3_v3fl(result, proj, flat);
        }
        break;
    }
    case PART_KINK_BRAID:
    {
        float y_vec[3]={0.f,1.f,0.f};
        float z_vec[3]={0.f,0.f,1.f};
        float vec_one[3], state_co[3];
        float inp_y, inp_z, length;

        if(par_rot) {
            mul_qt_v3(par_rot, y_vec);
            mul_qt_v3(par_rot, z_vec);
        }
        
        negate_v3(par_vec);
        normalize_v3_v3(vec_one, par_vec);

        inp_y=dot_v3v3(y_vec, vec_one);
        inp_z=dot_v3v3(z_vec, vec_one);

        if(inp_y > 0.5f){
            copy_v3_v3(state_co, y_vec);

            mul_v3_fl(y_vec, amplitude*(float)cos(t));
            mul_v3_fl(z_vec, amplitude/2.f*(float)sin(2.f*t));
        }
        else if(inp_z > 0.0f){
            mul_v3_v3fl(state_co, z_vec, (float)sin((float)M_PI/3.f));
            madd_v3_v3fl(state_co, y_vec, -0.5f);

            mul_v3_fl(y_vec, -amplitude * (float)cos(t + (float)M_PI/3.f));
            mul_v3_fl(z_vec, amplitude/2.f * (float)cos(2.f*t + (float)M_PI/6.f));
        }
        else{
            mul_v3_v3fl(state_co, z_vec, -(float)sin((float)M_PI/3.f));
            madd_v3_v3fl(state_co, y_vec, -0.5f);

            mul_v3_fl(y_vec, amplitude * (float)-sin(t + (float)M_PI/6.f));
            mul_v3_fl(z_vec, amplitude/2.f * (float)-sin(2.f*t + (float)M_PI/3.f));
        }

        mul_v3_fl(state_co, amplitude);
        add_v3_v3(state_co, par->co);
        sub_v3_v3v3(par_vec, state->co, state_co);

        length = normalize_v3(par_vec);
        mul_v3_fl(par_vec, MIN2(length, amplitude/2.f));

        add_v3_v3v3(state_co, par->co, y_vec);
        add_v3_v3(state_co, z_vec);
        add_v3_v3(state_co, par_vec);

        shape = 2.f*(float)M_PI * (1.f+shape);

        if(t<shape){
            shape = t/shape;
            shape = (float)sqrt((double)shape);
            interp_v3_v3v3(result, result, state_co, shape);
        }
        else{
            copy_v3_v3(result, state_co);
        }
        break;
    }
    }

    /* blend the start of the kink */
    if(dt < 1.f)
        interp_v3_v3v3(state->co, state->co, result, dt);
    else
        copy_v3_v3(state->co, result);
}

static float do_clump(ParticleKey *state, ParticleKey *par, float time, float clumpfac, float clumppow, float pa_clump)
{
    float clump = 0.f;

    if(par && clumpfac!=0.0f){
        float cpow;

        if(clumppow < 0.0f)
            cpow=1.0f+clumppow;
        else
            cpow=1.0f+9.0f*clumppow;

        if(clumpfac < 0.0f) /* clump roots instead of tips */
            clump = -clumpfac*pa_clump*(float)pow(1.0-(double)time,(double)cpow);
        else
            clump = clumpfac*pa_clump*(float)pow((double)time,(double)cpow);

        interp_v3_v3v3(state->co,state->co,par->co,clump);
    }

    return clump;
}
void precalc_guides(ParticleSimulationData *sim, ListBase *effectors)
{
    EffectedPoint point;
    ParticleKey state;
    EffectorData efd;
    EffectorCache *eff;
    ParticleSystem *psys = sim->psys;
    EffectorWeights *weights = sim->psys->part->effector_weights;
    GuideEffectorData *data;
    PARTICLE_P;

    if(!effectors)
        return;

    LOOP_PARTICLES {
        psys_particle_on_emitter(sim->psmd,sim->psys->part->from,pa->num,pa->num_dmcache,pa->fuv,pa->foffset,state.co,0,0,0,0,0);
        
        mul_m4_v3(sim->ob->obmat, state.co);
        mul_mat3_m4_v3(sim->ob->obmat, state.vel);
        
        pd_point_from_particle(sim, pa, &state, &point);

        for(eff = effectors->first; eff; eff=eff->next) {
            if(eff->pd->forcefield != PFIELD_GUIDE)
                continue;

            if(!eff->guide_data)
                eff->guide_data = MEM_callocN(sizeof(GuideEffectorData)*psys->totpart, "GuideEffectorData");

            data = eff->guide_data + p;

            sub_v3_v3v3(efd.vec_to_point, state.co, eff->guide_loc);
            copy_v3_v3(efd.nor, eff->guide_dir);
            efd.distance = len_v3(efd.vec_to_point);

            copy_v3_v3(data->vec_to_point, efd.vec_to_point);
            data->strength = effector_falloff(eff, &efd, &point, weights);
        }
    }
}
int do_guides(ListBase *effectors, ParticleKey *state, int index, float time)
{
    EffectorCache *eff;
    PartDeflect *pd;
    Curve *cu;
    ParticleKey key, par;
    GuideEffectorData *data;

    float effect[3] = {0.0f, 0.0f, 0.0f}, veffect[3] = {0.0f, 0.0f, 0.0f};
    float guidevec[4], guidedir[3], rot2[4], temp[3];
    float guidetime, radius, weight, angle, totstrength = 0.0f;
    float vec_to_point[3];

    if(effectors) for(eff = effectors->first; eff; eff=eff->next) {
        pd = eff->pd;

        if(pd->forcefield != PFIELD_GUIDE)
            continue;

        data = eff->guide_data + index;

        if(data->strength <= 0.0f)
            continue;

        guidetime = time / (1.0f - pd->free_end);

        if(guidetime>1.0f)
            continue;

        cu = (Curve*)eff->ob->data;

        if(pd->flag & PFIELD_GUIDE_PATH_ADD) {
            if(where_on_path(eff->ob, data->strength * guidetime, guidevec, guidedir, NULL, &radius, &weight)==0)
                return 0;
        }
        else {
            if(where_on_path(eff->ob, guidetime, guidevec, guidedir, NULL, &radius, &weight)==0)
                return 0;
        }

        mul_m4_v3(eff->ob->obmat, guidevec);
        mul_mat3_m4_v3(eff->ob->obmat, guidedir);

        normalize_v3(guidedir);

        copy_v3_v3(vec_to_point, data->vec_to_point);

        if(guidetime != 0.0f) {
            /* curve direction */
            cross_v3_v3v3(temp, eff->guide_dir, guidedir);
            angle = dot_v3v3(eff->guide_dir, guidedir)/(len_v3(eff->guide_dir));
            angle = saacos(angle);
            axis_angle_to_quat( rot2,temp, angle);
            mul_qt_v3(rot2, vec_to_point);

            /* curve tilt */
            axis_angle_to_quat( rot2,guidedir, guidevec[3] - eff->guide_loc[3]);
            mul_qt_v3(rot2, vec_to_point);
        }

        /* curve taper */
        if(cu->taperobj)
            mul_v3_fl(vec_to_point, calc_taper(eff->scene, cu->taperobj, (int)(data->strength*guidetime*100.0f), 100));

        else{ /* curve size*/
            if(cu->flag & CU_PATH_RADIUS) {
                mul_v3_fl(vec_to_point, radius);
            }
        }
        par.co[0] = par.co[1] = par.co[2] = 0.0f;
        copy_v3_v3(key.co, vec_to_point);
        do_kink(&key, &par, 0, guidetime, pd->kink_freq, pd->kink_shape, pd->kink_amp, 0.f, pd->kink, pd->kink_axis, 0, 0);
        do_clump(&key, &par, guidetime, pd->clump_fac, pd->clump_pow, 1.0f);
        copy_v3_v3(vec_to_point, key.co);

        add_v3_v3(vec_to_point, guidevec);

        //sub_v3_v3v3(pa_loc,pa_loc,pa_zero);
        madd_v3_v3fl(effect, vec_to_point, data->strength);
        madd_v3_v3fl(veffect, guidedir, data->strength);
        totstrength += data->strength;

        if(pd->flag & PFIELD_GUIDE_PATH_WEIGHT)
            totstrength *= weight;
    }

    if(totstrength != 0.0f){
        if(totstrength > 1.0f)
            mul_v3_fl(effect, 1.0f / totstrength);
        CLAMP(totstrength, 0.0f, 1.0f);
        //add_v3_v3(effect,pa_zero);
        interp_v3_v3v3(state->co, state->co, effect, totstrength);

        normalize_v3(veffect);
        mul_v3_fl(veffect, len_v3(state->vel));
        copy_v3_v3(state->vel, veffect);
        return 1;
    }
    return 0;
}
static void do_rough(float *loc, float mat[4][4], float t, float fac, float size, float thres, ParticleKey *state)
{
    float rough[3];
    float rco[3];

    if(thres != 0.0f)
        if((float)fabs((float)(-1.5f+loc[0]+loc[1]+loc[2]))<1.5f*thres) return;

    copy_v3_v3(rco,loc);
    mul_v3_fl(rco,t);
    rough[0]=-1.0f+2.0f*BLI_gTurbulence(size, rco[0], rco[1], rco[2], 2,0,2);
    rough[1]=-1.0f+2.0f*BLI_gTurbulence(size, rco[1], rco[2], rco[0], 2,0,2);
    rough[2]=-1.0f+2.0f*BLI_gTurbulence(size, rco[2], rco[0], rco[1], 2,0,2);

    madd_v3_v3fl(state->co, mat[0], fac * rough[0]);
    madd_v3_v3fl(state->co, mat[1], fac * rough[1]);
    madd_v3_v3fl(state->co, mat[2], fac * rough[2]);
}
static void do_rough_end(float *loc, float mat[4][4], float t, float fac, float shape, ParticleKey *state)
{
    float rough[2];
    float roughfac;

    roughfac=fac*(float)pow((double)t,shape);
    copy_v2_v2(rough,loc);
    rough[0]=-1.0f+2.0f*rough[0];
    rough[1]=-1.0f+2.0f*rough[1];
    mul_v2_fl(rough,roughfac);

    madd_v3_v3fl(state->co, mat[0], rough[0]);
    madd_v3_v3fl(state->co, mat[1], rough[1]);
}
static void do_path_effectors(ParticleSimulationData *sim, int i, ParticleCacheKey *ca, int k, int steps, float *UNUSED(rootco), float effector, float UNUSED(dfra), float UNUSED(cfra), float *length, float *vec)
{
    float force[3] = {0.0f,0.0f,0.0f};
    ParticleKey eff_key;
    EffectedPoint epoint;

    /* Don't apply effectors for dynamic hair, otherwise the effectors don't get applied twice. */
    if(sim->psys->flag & PSYS_HAIR_DYNAMICS)
        return;

    copy_v3_v3(eff_key.co,(ca-1)->co);
    copy_v3_v3(eff_key.vel,(ca-1)->vel);
    copy_qt_qt(eff_key.rot,(ca-1)->rot);

    pd_point_from_particle(sim, sim->psys->particles+i, &eff_key, &epoint);
    pdDoEffectors(sim->psys->effectors, sim->colliders, sim->psys->part->effector_weights, &epoint, force, NULL);

    mul_v3_fl(force, effector*powf((float)k / (float)steps, 100.0f * sim->psys->part->eff_hair) / (float)steps);

    add_v3_v3(force, vec);

    normalize_v3(force);

    if(k < steps)
        sub_v3_v3v3(vec, (ca+1)->co, ca->co);

    madd_v3_v3v3fl(ca->co, (ca-1)->co, force, *length);

    if(k < steps)
        *length = len_v3(vec);
}
static int check_path_length(int k, ParticleCacheKey *keys, ParticleCacheKey *state, float max_length, float *cur_length, float length, float *dvec)
{
    if(*cur_length + length > max_length){
        mul_v3_fl(dvec, (max_length - *cur_length) / length);
        add_v3_v3v3(state->co, (state - 1)->co, dvec);
        keys->steps = k;
        /* something over the maximum step value */
        return k=100000;
    }
    else {
        *cur_length+=length;
        return k;
    }
}
static void offset_child(ChildParticle *cpa, ParticleKey *par, float *par_rot, ParticleKey *child, float flat, float radius)
{
    copy_v3_v3(child->co, cpa->fuv);
    mul_v3_fl(child->co, radius);

    child->co[0]*=flat;

    copy_v3_v3(child->vel, par->vel);

    if(par_rot) {
        mul_qt_v3(par_rot, child->co);
        copy_qt_qt(child->rot, par_rot);
    }
    else
        unit_qt(child->rot);

    add_v3_v3(child->co, par->co);
}
float *psys_cache_vgroup(DerivedMesh *dm, ParticleSystem *psys, int vgroup)
{
    float *vg=0;

    if(vgroup < 0) {
        /* hair dynamics pinning vgroup */

    }
    else if(psys->vgroup[vgroup]){
        MDeformVert *dvert = dm->getVertDataArray(dm, CD_MDEFORMVERT);
        if(dvert){
            int totvert=dm->getNumVerts(dm), i;
            vg=MEM_callocN(sizeof(float)*totvert, "vg_cache");
            if(psys->vg_neg&(1<<vgroup)){
                for(i=0; i<totvert; i++)
                    vg[i]= 1.0f - defvert_find_weight(&dvert[i], psys->vgroup[vgroup] - 1);
            }
            else{
                for(i=0; i<totvert; i++)
                    vg[i]=  defvert_find_weight(&dvert[i], psys->vgroup[vgroup] - 1);
            }
        }
    }
    return vg;
}
void psys_find_parents(ParticleSimulationData *sim)
{
    ParticleSettings *part=sim->psys->part;
    KDTree *tree;
    ChildParticle *cpa;
    int p, totparent,totchild=sim->psys->totchild;
    float co[3], orco[3];
    int from=PART_FROM_FACE;
    totparent=(int)(totchild*part->parents*0.3f);

    if(G.rendering && part->child_nbr && part->ren_child_nbr)
        totparent*=(float)part->child_nbr/(float)part->ren_child_nbr;

    tree=BLI_kdtree_new(totparent);

    for(p=0,cpa=sim->psys->child; p<totparent; p++,cpa++){
        psys_particle_on_emitter(sim->psmd,from,cpa->num,DMCACHE_ISCHILD,cpa->fuv,cpa->foffset,co,0,0,0,orco,0);
        BLI_kdtree_insert(tree, p, orco, NULL);
    }

    BLI_kdtree_balance(tree);

    for(; p<totchild; p++,cpa++){
        psys_particle_on_emitter(sim->psmd,from,cpa->num,DMCACHE_ISCHILD,cpa->fuv,cpa->foffset,co,0,0,0,orco,0);
        cpa->parent=BLI_kdtree_find_nearest(tree, orco, NULL, NULL);
    }

    BLI_kdtree_free(tree);
}

static void get_strand_normal(Material *ma, float *surfnor, float surfdist, float *nor)
{
    float cross[3], nstrand[3], vnor[3], blend;

    if(!((ma->mode & MA_STR_SURFDIFF) || (ma->strand_surfnor > 0.0f)))
        return;

    if(ma->mode & MA_STR_SURFDIFF) {
        cross_v3_v3v3(cross, surfnor, nor);
        cross_v3_v3v3(nstrand, nor, cross);

        blend= INPR(nstrand, surfnor);
        CLAMP(blend, 0.0f, 1.0f);

        interp_v3_v3v3(vnor, nstrand, surfnor, blend);
        normalize_v3(vnor);
    }
    else {
        copy_v3_v3(vnor, nor);
    }
    
    if(ma->strand_surfnor > 0.0f) {
        if(ma->strand_surfnor > surfdist) {
            blend= (ma->strand_surfnor - surfdist)/ma->strand_surfnor;
            interp_v3_v3v3(vnor, vnor, surfnor, blend);
            normalize_v3(vnor);
        }
    }

    copy_v3_v3(nor, vnor);
}

static int psys_threads_init_path(ParticleThread *threads, Scene *scene, float cfra, int editupdate)
{
    ParticleThreadContext *ctx= threads[0].ctx;
/*  Object *ob= ctx->sim.ob; */
    ParticleSystem *psys= ctx->sim.psys;
    ParticleSettings *part = psys->part;
/*  ParticleEditSettings *pset = &scene->toolsettings->particle; */
    int totparent=0, between=0;
    int steps = (int)pow(2.0, (double)part->draw_step);
    int totchild = psys->totchild;
    int i, seed, totthread= threads[0].tot;

    /*---start figuring out what is actually wanted---*/
    if(psys_in_edit_mode(scene, psys)) {
        ParticleEditSettings *pset = &scene->toolsettings->particle;

        if(psys->renderdata==0 && (psys->edit==NULL || pset->flag & PE_DRAW_PART)==0)
            totchild=0;

        steps = (int)pow(2.0, (double)pset->draw_step);
    }

    if(totchild && part->childtype==PART_CHILD_FACES){
        totparent=(int)(totchild*part->parents*0.3f);
        
        if(G.rendering && part->child_nbr && part->ren_child_nbr)
            totparent*=(float)part->child_nbr/(float)part->ren_child_nbr;

        /* part->parents could still be 0 so we can't test with totparent */
        between=1;
    }

    if(psys->renderdata)
        steps=(int)pow(2.0,(double)part->ren_step);
    else{
        totchild=(int)((float)totchild*(float)part->disp/100.0f);
        totparent=MIN2(totparent,totchild);
    }

    if(totchild==0) return 0;

    /* init random number generator */
    seed= 31415926 + ctx->sim.psys->seed;
    
    if(ctx->editupdate || totchild < 10000)
        totthread= 1;
    
    for(i=0; i<totthread; i++) {
        threads[i].rng_path= rng_new(seed);
        threads[i].tot= totthread;
    }

    /* fill context values */
    ctx->between= between;
    ctx->steps= steps;
    ctx->totchild= totchild;
    ctx->totparent= totparent;
    ctx->parent_pass= 0;
    ctx->cfra= cfra;
    ctx->editupdate= editupdate;

    psys->lattice = psys_get_lattice(&ctx->sim);

    /* cache all relevant vertex groups if they exist */
    ctx->vg_length = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_LENGTH);
    ctx->vg_clump = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_CLUMP);
    ctx->vg_kink = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_KINK);
    ctx->vg_rough1 = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_ROUGH1);
    ctx->vg_rough2 = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_ROUGH2);
    ctx->vg_roughe = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_ROUGHE);
    if(psys->part->flag & PART_CHILD_EFFECT)
        ctx->vg_effector = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_EFFECTOR);

    /* set correct ipo timing */
#if 0 // XXX old animation system
    if(part->flag&PART_ABS_TIME && part->ipo){
        calc_ipo(part->ipo, cfra);
        execute_ipo((ID *)part, part->ipo);
    }
#endif // XXX old animation system

    return 1;
}

/* note: this function must be thread safe, except for branching! */
static void psys_thread_create_path(ParticleThread *thread, struct ChildParticle *cpa, ParticleCacheKey *child_keys, int i)
{
    ParticleThreadContext *ctx= thread->ctx;
    Object *ob= ctx->sim.ob;
    ParticleSystem *psys = ctx->sim.psys;
    ParticleSettings *part = psys->part;
    ParticleCacheKey **cache= psys->childcache;
    ParticleCacheKey **pcache= psys_in_edit_mode(ctx->sim.scene, psys) ? psys->edit->pathcache : psys->pathcache;
    ParticleCacheKey *child, *par = NULL, *key[4];
    ParticleTexture ptex;
    float *cpa_fuv=0, *par_rot=0, rot[4];
    float orco[3], ornor[3], hairmat[4][4], t, dvec[3], off1[4][3], off2[4][3];
    float length, max_length = 1.0f, cur_length = 0.0f;
    float eff_length, eff_vec[3], weight[4];
    int k, cpa_num;
    short cpa_from;

    if(!pcache)
        return;

    if(ctx->between){
        ParticleData *pa = psys->particles + cpa->pa[0];
        int w, needupdate;
        float foffset, wsum=0.f;
        float co[3];
        float p_min = part->parting_min;
        float p_max = part->parting_max;
        /* Virtual parents don't work nicely with parting. */
        float p_fac = part->parents > 0.f ? 0.f : part->parting_fac;

        if(ctx->editupdate) {
            needupdate= 0;
            w= 0;
            while(w<4 && cpa->pa[w]>=0) {
                if(psys->edit->points[cpa->pa[w]].flag & PEP_EDIT_RECALC) {
                    needupdate= 1;
                    break;
                }
                w++;
            }

            if(!needupdate)
                return;
            else
                memset(child_keys, 0, sizeof(*child_keys)*(ctx->steps+1));
        }

        /* get parent paths */
        for(w=0; w<4; w++) {
            if(cpa->pa[w] >= 0) {
                key[w] = pcache[cpa->pa[w]];
                weight[w] = cpa->w[w];
            }
            else {
                key[w] = pcache[0];
                weight[w] = 0.f;
            }
        }

        /* modify weights to create parting */
        if(p_fac > 0.f) {
            for(w=0; w<4; w++) {
                if(w && weight[w] > 0.f) {
                    float d;
                    if(part->flag & PART_CHILD_LONG_HAIR) {
                        /* For long hair use tip distance/root distance as parting factor instead of root to tip angle. */
                        float d1 = len_v3v3(key[0]->co, key[w]->co);
                        float d2 = len_v3v3((key[0]+key[0]->steps-1)->co, (key[w]+key[w]->steps-1)->co);

                        d = d1 > 0.f ? d2/d1 - 1.f : 10000.f;
                    }
                    else {
                        float v1[3], v2[3];
                        sub_v3_v3v3(v1, (key[0]+key[0]->steps-1)->co, key[0]->co);
                        sub_v3_v3v3(v2, (key[w]+key[w]->steps-1)->co, key[w]->co);
                        normalize_v3(v1);
                        normalize_v3(v2);

                        d = RAD2DEGF(saacos(dot_v3v3(v1, v2)));
                    }

                    if(p_max > p_min)
                        d = (d - p_min)/(p_max - p_min);
                    else
                        d = (d - p_min) <= 0.f ? 0.f : 1.f;

                    CLAMP(d, 0.f, 1.f);

                    if(d > 0.f)
                        weight[w] *= (1.f - d);
                }
                wsum += weight[w];
            }
            for(w=0; w<4; w++)
                weight[w] /= wsum;

            interp_v4_v4v4(weight, cpa->w, weight, p_fac);
        }

        /* get the original coordinates (orco) for texture usage */
        cpa_num = cpa->num;
        
        foffset = cpa->foffset;
        cpa_fuv = cpa->fuv;
        cpa_from = PART_FROM_FACE;

        psys_particle_on_emitter(ctx->sim.psmd,cpa_from,cpa_num,DMCACHE_ISCHILD,cpa->fuv,foffset,co,ornor,0,0,orco,0);

        mul_m4_v3(ob->obmat, co);

        for(w=0; w<4; w++)
            sub_v3_v3v3(off1[w], co, key[w]->co);

        psys_mat_hair_to_global(ob, ctx->sim.psmd->dm, psys->part->from, pa, hairmat);
    }
    else{
        ParticleData *pa = psys->particles + cpa->parent;
        float co[3];
        if(ctx->editupdate) {
            if(!(psys->edit->points[cpa->parent].flag & PEP_EDIT_RECALC))
                return;

            memset(child_keys, 0, sizeof(*child_keys)*(ctx->steps+1));
        }

        /* get the parent path */
        key[0] = pcache[cpa->parent];

        /* get the original coordinates (orco) for texture usage */
        cpa_from = part->from;
        cpa_num = pa->num;
        cpa_fuv = pa->fuv;

        psys_particle_on_emitter(ctx->sim.psmd,cpa_from,cpa_num,DMCACHE_ISCHILD,cpa_fuv,pa->foffset,co,ornor,0,0,orco,0);

        psys_mat_hair_to_global(ob, ctx->sim.psmd->dm, psys->part->from, pa, hairmat);
    }

    child_keys->steps = ctx->steps;

    /* get different child parameters from textures & vgroups */
    get_child_modifier_parameters(part, ctx, cpa, cpa_from, cpa_num, cpa_fuv, orco, &ptex);

    if(ptex.exist < PSYS_FRAND(i + 24)) {
        child_keys->steps = -1;
        return;
    }

    /* create the child path */
    for(k=0,child=child_keys; k<=ctx->steps; k++,child++){
        if(ctx->between){
            int w=0;

            zero_v3(child->co);
            zero_v3(child->vel);
            unit_qt(child->rot);

            for(w=0; w<4; w++) {
                copy_v3_v3(off2[w], off1[w]);

                if(part->flag & PART_CHILD_LONG_HAIR) {
                    /* Use parent rotation (in addition to emission location) to determine child offset. */
                    if(k)
                        mul_qt_v3((key[w]+k)->rot, off2[w]);

                    /* Fade the effect of rotation for even lengths in the end */
                    project_v3_v3v3(dvec, off2[w], (key[w]+k)->vel);
                    madd_v3_v3fl(off2[w], dvec, -(float)k/(float)ctx->steps);
                }

                add_v3_v3(off2[w], (key[w]+k)->co);
            }

            /* child position is the weighted sum of parent positions */
            interp_v3_v3v3v3v3(child->co, off2[0], off2[1], off2[2], off2[3], weight);
            interp_v3_v3v3v3v3(child->vel, (key[0]+k)->vel, (key[1]+k)->vel, (key[2]+k)->vel, (key[3]+k)->vel, weight);

            copy_qt_qt(child->rot, (key[0]+k)->rot);
        }
        else{
            if(k) {
                mul_qt_qtqt(rot, (key[0]+k)->rot, key[0]->rot);
                par_rot = rot;
            }
            else {
                par_rot = key[0]->rot;
            }
            /* offset the child from the parent position */
            offset_child(cpa, (ParticleKey*)(key[0]+k), par_rot, (ParticleKey*)child, part->childflat, part->childrad);
        }
    }

    /* apply effectors */
    if(part->flag & PART_CHILD_EFFECT) {
        for(k=0,child=child_keys; k<=ctx->steps; k++,child++) {
            if(k) {
                do_path_effectors(&ctx->sim, cpa->pa[0], child, k, ctx->steps, child_keys->co, ptex.effector, 0.0f, ctx->cfra, &eff_length, eff_vec);
            }
            else {
                sub_v3_v3v3(eff_vec, (child+1)->co, child->co);
                eff_length = len_v3(eff_vec);
            }
        }
    }

    for(k=0,child=child_keys; k<=ctx->steps; k++,child++){
        t = (float)k/(float)ctx->steps;

        if(ctx->totparent)
            /* this is now threadsafe, virtual parents are calculated before rest of children */
            par = (i >= ctx->totparent) ? cache[cpa->parent] : NULL;
        else if(cpa->parent >= 0)
            par = pcache[cpa->parent];

        if(par) {
            if(k) {
                mul_qt_qtqt(rot, (par+k)->rot, par->rot);
                par_rot = rot;
            }
            else {
                par_rot = par->rot;
            }
            par += k;
        }

        /* apply different deformations to the child path */
        do_child_modifiers(&ctx->sim, &ptex, (ParticleKey *)par, par_rot, cpa, orco, hairmat, (ParticleKey *)child, t);

        /* we have to correct velocity because of kink & clump */
        if(k>1){
            sub_v3_v3v3((child-1)->vel, child->co, (child-2)->co);
            mul_v3_fl((child-1)->vel, 0.5);

            if(ctx->ma && (part->draw_col == PART_DRAW_COL_MAT))
                get_strand_normal(ctx->ma, ornor, cur_length, (child-1)->vel);
        }

        if(k == ctx->steps)
            sub_v3_v3v3(child->vel, child->co, (child-1)->co);

        /* check if path needs to be cut before actual end of data points */
        if(k){
            sub_v3_v3v3(dvec, child->co, (child-1)->co);
            length = 1.0f/(float)ctx->steps;
            k = check_path_length(k, child_keys, child, max_length, &cur_length, length, dvec);
        }
        else{
            /* initialize length calculation */
            max_length = ptex.length;
            cur_length = 0.0f;
        }

        if(ctx->ma && (part->draw_col == PART_DRAW_COL_MAT)) {
            copy_v3_v3(child->col, &ctx->ma->r);
            get_strand_normal(ctx->ma, ornor, cur_length, child->vel);
        }
    }

    /* Hide virtual parents */
    if(i < ctx->totparent)
        child_keys->steps = -1;
}

static void *exec_child_path_cache(void *data)
{
    ParticleThread *thread= (ParticleThread*)data;
    ParticleThreadContext *ctx= thread->ctx;
    ParticleSystem *psys= ctx->sim.psys;
    ParticleCacheKey **cache= psys->childcache;
    ChildParticle *cpa;
    int i, totchild= ctx->totchild, first= 0;

    if(thread->tot > 1){
        first= ctx->parent_pass? 0 : ctx->totparent;
        totchild= ctx->parent_pass? ctx->totparent : ctx->totchild;
    }
    
    cpa= psys->child + first + thread->num;
    for(i=first+thread->num; i<totchild; i+=thread->tot, cpa+=thread->tot)
        psys_thread_create_path(thread, cpa, cache[i], i);

    return 0;
}

void psys_cache_child_paths(ParticleSimulationData *sim, float cfra, int editupdate)
{
    ParticleThread *pthreads;
    ParticleThreadContext *ctx;
    ListBase threads;
    int i, totchild, totparent, totthread;

    if(sim->psys->flag & PSYS_GLOBAL_HAIR)
        return;

    pthreads= psys_threads_create(sim);

    if(!psys_threads_init_path(pthreads, sim->scene, cfra, editupdate)) {
        psys_threads_free(pthreads);
        return;
    }

    ctx= pthreads[0].ctx;
    totchild= ctx->totchild;
    totparent= ctx->totparent;

    if(editupdate && sim->psys->childcache && totchild == sim->psys->totchildcache) {
        ; /* just overwrite the existing cache */
    }
    else {
        /* clear out old and create new empty path cache */
        free_child_path_cache(sim->psys);
        sim->psys->childcache= psys_alloc_path_cache_buffers(&sim->psys->childcachebufs, totchild, ctx->steps+1);
        sim->psys->totchildcache = totchild;
    }

    totthread= pthreads[0].tot;

    if(totthread > 1) {

        /* make virtual child parents thread safe by calculating them first */
        if(totparent) {
            BLI_init_threads(&threads, exec_child_path_cache, totthread);
            
            for(i=0; i<totthread; i++) {
                pthreads[i].ctx->parent_pass = 1;
                BLI_insert_thread(&threads, &pthreads[i]);
            }

            BLI_end_threads(&threads);

            for(i=0; i<totthread; i++)
                pthreads[i].ctx->parent_pass = 0;
        }

        BLI_init_threads(&threads, exec_child_path_cache, totthread);

        for(i=0; i<totthread; i++)
            BLI_insert_thread(&threads, &pthreads[i]);

        BLI_end_threads(&threads);
    }
    else
        exec_child_path_cache(&pthreads[0]);

    psys_threads_free(pthreads);
}
/* figure out incremental rotations along path starting from unit quat */
static void cache_key_incremental_rotation(ParticleCacheKey *key0, ParticleCacheKey *key1, ParticleCacheKey *key2, float *prev_tangent, int i)
{
    float cosangle, angle, tangent[3], normal[3], q[4];

    switch(i) {
    case 0:
        /* start from second key */
        break;
    case 1:
        /* calculate initial tangent for incremental rotations */
        sub_v3_v3v3(prev_tangent, key0->co, key1->co);
        normalize_v3(prev_tangent);
        unit_qt(key1->rot);
        break;
    default:
        sub_v3_v3v3(tangent, key0->co, key1->co);
        normalize_v3(tangent);

        cosangle= dot_v3v3(tangent, prev_tangent);

        /* note we do the comparison on cosangle instead of
        * angle, since floating point accuracy makes it give
        * different results across platforms */
        if(cosangle > 0.999999f) {
            copy_v4_v4(key1->rot, key2->rot);
        }
        else {
            angle= saacos(cosangle);
            cross_v3_v3v3(normal, prev_tangent, tangent);
            axis_angle_to_quat( q,normal, angle);
            mul_qt_qtqt(key1->rot, q, key2->rot);
        }

        copy_v3_v3(prev_tangent, tangent);
    }
}
/* Calculates paths ready for drawing/rendering.                                    */
/* -Usefull for making use of opengl vertex arrays for super fast strand drawing.   */
/* -Makes child strands possible and creates them too into the cache.               */
/* -Cached path data is also used to determine cut position for the editmode tool.  */
void psys_cache_paths(ParticleSimulationData *sim, float cfra)
{
    PARTICLE_PSMD;
    ParticleEditSettings *pset = &sim->scene->toolsettings->particle;
    ParticleSystem *psys = sim->psys;
    ParticleSettings *part = psys->part;
    ParticleCacheKey *ca, **cache;

    DerivedMesh *hair_dm = (psys->part->type==PART_HAIR && psys->flag & PSYS_HAIR_DYNAMICS) ? psys->hair_out_dm : NULL;
    
    ParticleKey result;
    
    Material *ma;
    ParticleInterpolationData pind;
    ParticleTexture ptex;

    PARTICLE_P;
    
    float birthtime = 0.0, dietime = 0.0;
    float t, time = 0.0, dfra = 1.0 /* , frs_sec = sim->scene->r.frs_sec*/ /*UNUSED*/;
    float col[4] = {0.5f, 0.5f, 0.5f, 1.0f};
    float prev_tangent[3] = {0.0f, 0.0f, 0.0f}, hairmat[4][4];
    float rotmat[3][3];
    int k;
    int steps = (int)pow(2.0, (double)(psys->renderdata ? part->ren_step : part->draw_step));
    int totpart = psys->totpart;
    float length, vec[3];
    float *vg_effector= NULL;
    float *vg_length= NULL, pa_length=1.0f;
    int keyed, baked;

    /* we don't have anything valid to create paths from so let's quit here */
    if((psys->flag & PSYS_HAIR_DONE || psys->flag & PSYS_KEYED || psys->pointcache)==0)
        return;

    if(psys_in_edit_mode(sim->scene, psys))
        if(psys->renderdata==0 && (psys->edit==NULL || pset->flag & PE_DRAW_PART)==0)
            return;

    keyed = psys->flag & PSYS_KEYED;
    baked = psys->pointcache->mem_cache.first && psys->part->type != PART_HAIR;

    /* clear out old and create new empty path cache */
    psys_free_path_cache(psys, psys->edit);
    cache= psys->pathcache= psys_alloc_path_cache_buffers(&psys->pathcachebufs, totpart, steps+1);

    psys->lattice = psys_get_lattice(sim);
    ma= give_current_material(sim->ob, psys->part->omat);
    if(ma && (psys->part->draw_col == PART_DRAW_COL_MAT))
        copy_v3_v3(col, &ma->r);

    if((psys->flag & PSYS_GLOBAL_HAIR)==0) {
        if((psys->part->flag & PART_CHILD_EFFECT)==0)
            vg_effector = psys_cache_vgroup(psmd->dm, psys, PSYS_VG_EFFECTOR);
        
        if(!psys->totchild)
            vg_length = psys_cache_vgroup(psmd->dm, psys, PSYS_VG_LENGTH);
    }

    /*---first main loop: create all actual particles' paths---*/
    LOOP_SHOWN_PARTICLES {
        if(!psys->totchild) {
            psys_get_texture(sim, pa, &ptex, PAMAP_LENGTH, 0.f);
            pa_length = ptex.length * (1.0f - part->randlength * PSYS_FRAND(psys->seed + p));
            if(vg_length)
                pa_length *= psys_particle_value_from_verts(psmd->dm,part->from,pa,vg_length);
        }

        pind.keyed = keyed;
        pind.cache = baked ? psys->pointcache : NULL;
        pind.epoint = NULL;
        pind.bspline = (psys->part->flag & PART_HAIR_BSPLINE);
        pind.dm = hair_dm;

        memset(cache[p], 0, sizeof(*cache[p])*(steps+1));

        cache[p]->steps = steps;

        /*--get the first data points--*/
        init_particle_interpolation(sim->ob, sim->psys, pa, &pind);

        /* hairmat is needed for for non-hair particle too so we get proper rotations */
        psys_mat_hair_to_global(sim->ob, psmd->dm, psys->part->from, pa, hairmat);
        copy_v3_v3(rotmat[0], hairmat[2]);
        copy_v3_v3(rotmat[1], hairmat[1]);
        copy_v3_v3(rotmat[2], hairmat[0]);

        if(part->draw & PART_ABS_PATH_TIME) {
            birthtime = MAX2(pind.birthtime, part->path_start);
            dietime = MIN2(pind.dietime, part->path_end);
        }
        else {
            float tb = pind.birthtime;
            birthtime = tb + part->path_start * (pind.dietime - tb);
            dietime = tb + part->path_end * (pind.dietime - tb);
        }

        if(birthtime >= dietime) {
            cache[p]->steps = -1;
            continue;
        }

        dietime = birthtime + pa_length * (dietime - birthtime);

        /*--interpolate actual path from data points--*/
        for(k=0, ca=cache[p]; k<=steps; k++, ca++){
            time = (float)k / (float)steps;
            t = birthtime + time * (dietime - birthtime);
            result.time = -t;
            do_particle_interpolation(psys, p, pa, t, &pind, &result);
            copy_v3_v3(ca->co, result.co);

            /* dynamic hair is in object space */
            /* keyed and baked are already in global space */
            if(hair_dm)
                mul_m4_v3(sim->ob->obmat, ca->co);
            else if(!keyed && !baked && !(psys->flag & PSYS_GLOBAL_HAIR))
                mul_m4_v3(hairmat, ca->co);

            copy_v3_v3(ca->col, col);
        }
        
        /*--modify paths and calculate rotation & velocity--*/

        if(!(psys->flag & PSYS_GLOBAL_HAIR)) {
            /* apply effectors */
            if((psys->part->flag & PART_CHILD_EFFECT) == 0) {
                float effector= 1.0f;
                if(vg_effector)
                    effector*= psys_particle_value_from_verts(psmd->dm,psys->part->from,pa,vg_effector);

                sub_v3_v3v3(vec,(cache[p]+1)->co,cache[p]->co);
                length = len_v3(vec);

                for(k=1, ca=cache[p]+1; k<=steps; k++, ca++)
                    do_path_effectors(sim, p, ca, k, steps, cache[p]->co, effector, dfra, cfra, &length, vec);
            }

            /* apply guide curves to path data */
            if(sim->psys->effectors && (psys->part->flag & PART_CHILD_EFFECT)==0) {
                for(k=0, ca=cache[p]; k<=steps; k++, ca++)
                    /* ca is safe to cast, since only co and vel are used */
                    do_guides(sim->psys->effectors, (ParticleKey*)ca, p, (float)k/(float)steps);
            }

            /* lattices have to be calculated separately to avoid mixups between effector calculations */
            if(psys->lattice) {
                for(k=0, ca=cache[p]; k<=steps; k++, ca++)
                    calc_latt_deform(psys->lattice, ca->co, 1.0f);
            }
        }

        /* finally do rotation & velocity */
        for(k=1, ca=cache[p]+1; k<=steps; k++, ca++) {
            cache_key_incremental_rotation(ca, ca - 1, ca - 2, prev_tangent, k);

            if(k == steps)
                copy_qt_qt(ca->rot, (ca - 1)->rot);

            /* set velocity */
            sub_v3_v3v3(ca->vel, ca->co, (ca-1)->co);

            if(k==1)
                copy_v3_v3((ca-1)->vel, ca->vel);
        }
        /* First rotation is based on emitting face orientation.
         * This is way better than having flipping rotations resulting
         * from using a global axis as a rotation pole (vec_to_quat()).
         * It's not an ideal solution though since it disregards the
         * initial tangent, but taking that in to account will allow
         * the possibility of flipping again. -jahka
         */
        mat3_to_quat_is_ok(cache[p]->rot, rotmat);
    }

    psys->totcached = totpart;

    if(psys->lattice){
        end_latt_deform(psys->lattice);
        psys->lattice= NULL;
    }

    if(vg_effector)
        MEM_freeN(vg_effector);

    if(vg_length)
        MEM_freeN(vg_length);
}
void psys_cache_edit_paths(Scene *scene, Object *ob, PTCacheEdit *edit, float cfra)
{
    ParticleCacheKey *ca, **cache= edit->pathcache;
    ParticleEditSettings *pset = &scene->toolsettings->particle;
    
    PTCacheEditPoint *point = NULL;
    PTCacheEditKey *ekey = NULL;

    ParticleSystem *psys = edit->psys;
    ParticleSystemModifierData *psmd = psys_get_modifier(ob, psys);
    ParticleData *pa = psys ? psys->particles : NULL;

    ParticleInterpolationData pind;
    ParticleKey result;
    
    float birthtime = 0.0f, dietime = 0.0f;
    float t, time = 0.0f, keytime = 0.0f /*, frs_sec */;
    float hairmat[4][4], rotmat[3][3], prev_tangent[3] = {0.0f, 0.0f, 0.0f};
    int k, i;
    int steps = (int)pow(2.0, (double)pset->draw_step);
    int totpart = edit->totpoint, recalc_set=0;
    float sel_col[3];
    float nosel_col[3];

    steps = MAX2(steps, 4);

    if(!cache || edit->totpoint != edit->totcached) {
        /* clear out old and create new empty path cache */
        psys_free_path_cache(edit->psys, edit);
        cache= edit->pathcache= psys_alloc_path_cache_buffers(&edit->pathcachebufs, totpart, steps+1);

        /* set flag for update (child particles check this too) */
        for(i=0, point=edit->points; i<totpart; i++, point++)
            point->flag |= PEP_EDIT_RECALC;
        recalc_set = 1;
    }

    /* frs_sec = (psys || edit->pid.flag & PTCACHE_VEL_PER_SEC) ? 25.0f : 1.0f; */ /* UNUSED */

    if(pset->brushtype == PE_BRUSH_WEIGHT) {
        ;/* use weight painting colors now... */
    }
    else{
        sel_col[0] = (float)edit->sel_col[0] / 255.0f;
        sel_col[1] = (float)edit->sel_col[1] / 255.0f;
        sel_col[2] = (float)edit->sel_col[2] / 255.0f;
        nosel_col[0] = (float)edit->nosel_col[0] / 255.0f;
        nosel_col[1] = (float)edit->nosel_col[1] / 255.0f;
        nosel_col[2] = (float)edit->nosel_col[2] / 255.0f;
    }

    /*---first main loop: create all actual particles' paths---*/
    for(i=0, point=edit->points; i<totpart; i++, pa+=pa?1:0, point++){
        if(edit->totcached && !(point->flag & PEP_EDIT_RECALC))
            continue;

        ekey = point->keys;

        pind.keyed = 0;
        pind.cache = NULL;
        pind.epoint = point;
        pind.bspline = psys ? (psys->part->flag & PART_HAIR_BSPLINE) : 0;
        pind.dm = NULL;


        /* should init_particle_interpolation set this ? */
        if(pset->brushtype==PE_BRUSH_WEIGHT){
            pind.hkey[0] = NULL;
            /* pa != NULL since the weight brush is only available for hair */
            pind.hkey[1] = pa->hair;
        }


        memset(cache[i], 0, sizeof(*cache[i])*(steps+1));

        cache[i]->steps = steps;

        /*--get the first data points--*/
        init_particle_interpolation(ob, psys, pa, &pind);

        if(psys) {
            psys_mat_hair_to_global(ob, psmd->dm, psys->part->from, pa, hairmat);
            copy_v3_v3(rotmat[0], hairmat[2]);
            copy_v3_v3(rotmat[1], hairmat[1]);
            copy_v3_v3(rotmat[2], hairmat[0]);
        }

        birthtime = pind.birthtime;
        dietime = pind.dietime;

        if(birthtime >= dietime) {
            cache[i]->steps = -1;
            continue;
        }

        /*--interpolate actual path from data points--*/
        for(k=0, ca=cache[i]; k<=steps; k++, ca++){
            time = (float)k / (float)steps;
            t = birthtime + time * (dietime - birthtime);
            result.time = -t;
            do_particle_interpolation(psys, i, pa, t, &pind, &result);
            copy_v3_v3(ca->co, result.co);

             /* non-hair points are already in global space */
            if(psys && !(psys->flag & PSYS_GLOBAL_HAIR)) {
                mul_m4_v3(hairmat, ca->co);

                if(k) {
                    cache_key_incremental_rotation(ca, ca - 1, ca - 2, prev_tangent, k);

                    if(k == steps)
                        copy_qt_qt(ca->rot, (ca - 1)->rot);

                    /* set velocity */
                    sub_v3_v3v3(ca->vel, ca->co, (ca - 1)->co);

                    if(k==1)
                        copy_v3_v3((ca - 1)->vel, ca->vel);
                }
            }
            else {
                ca->vel[0] = ca->vel[1] = 0.0f;
                ca->vel[2] = 1.0f;
            }

            /* selection coloring in edit mode */
            if(pset->brushtype==PE_BRUSH_WEIGHT){
                float t2;

                if(k==0) {
                    weight_to_rgb(ca->col, pind.hkey[1]->weight);
                } else {
                    float w1[3], w2[3];
                    keytime = (t - (*pind.ekey[0]->time))/((*pind.ekey[1]->time) - (*pind.ekey[0]->time));

                    weight_to_rgb(w1, pind.hkey[0]->weight);
                    weight_to_rgb(w2, pind.hkey[1]->weight);

                    interp_v3_v3v3(ca->col, w1, w2, keytime);
                }

                /* at the moment this is only used for weight painting.
                 * will need to move out of this check if its used elsewhere. */
                t2 = birthtime + ((float)k/(float)steps) * (dietime - birthtime);

                while (pind.hkey[1]->time < t2) pind.hkey[1]++;
                pind.hkey[0] = pind.hkey[1] - 1;
            }
            else {
                if((ekey + (pind.ekey[0] - point->keys))->flag & PEK_SELECT){
                    if((ekey + (pind.ekey[1] - point->keys))->flag & PEK_SELECT){
                        copy_v3_v3(ca->col, sel_col);
                    }
                    else{
                        keytime = (t - (*pind.ekey[0]->time))/((*pind.ekey[1]->time) - (*pind.ekey[0]->time));
                        interp_v3_v3v3(ca->col, sel_col, nosel_col, keytime);
                    }
                }
                else{
                    if((ekey + (pind.ekey[1] - point->keys))->flag & PEK_SELECT){
                        keytime = (t - (*pind.ekey[0]->time))/((*pind.ekey[1]->time) - (*pind.ekey[0]->time));
                        interp_v3_v3v3(ca->col, nosel_col, sel_col, keytime);
                    }
                    else{
                        copy_v3_v3(ca->col, nosel_col);
                    }
                }
            }

            ca->time = t;
        }
        if(psys && !(psys->flag & PSYS_GLOBAL_HAIR)) {
            /* First rotation is based on emitting face orientation.
             * This is way better than having flipping rotations resulting
             * from using a global axis as a rotation pole (vec_to_quat()).
             * It's not an ideal solution though since it disregards the
             * initial tangent, but taking that in to account will allow
             * the possibility of flipping again. -jahka
             */
            mat3_to_quat_is_ok(cache[i]->rot, rotmat);
        }
    }

    edit->totcached = totpart;

    if(psys) {
        ParticleSimulationData sim= {0};
        sim.scene= scene;
        sim.ob= ob;
        sim.psys= psys;
        sim.psmd= psys_get_modifier(ob, psys);

        psys_cache_child_paths(&sim, cfra, 1);
    }

    /* clear recalc flag if set here */
    if(recalc_set) {
        for(i=0, point=edit->points; i<totpart; i++, point++)
            point->flag &= ~PEP_EDIT_RECALC;
    }
}
/************************************************/
/*          Particle Key handling               */
/************************************************/
void copy_particle_key(ParticleKey *to, ParticleKey *from, int time)
{
    if(time){
        memcpy(to,from,sizeof(ParticleKey));
    }
    else{
        float to_time=to->time;
        memcpy(to,from,sizeof(ParticleKey));
        to->time=to_time;
    }
}
void psys_get_from_key(ParticleKey *key, float *loc, float *vel, float *rot, float *time)
{
    if(loc) copy_v3_v3(loc,key->co);
    if(vel) copy_v3_v3(vel,key->vel);
    if(rot) copy_qt_qt(rot,key->rot);
    if(time) *time=key->time;
}
/*-------changing particle keys from space to another-------*/
#if 0
static void key_from_object(Object *ob, ParticleKey *key)
{
    float q[4];

    add_v3_v3(key->vel, key->co);

    mul_m4_v3(ob->obmat,key->co);
    mul_m4_v3(ob->obmat,key->vel);
    mat4_to_quat(q,ob->obmat);

    sub_v3_v3v3(key->vel,key->vel,key->co);
    mul_qt_qtqt(key->rot,q,key->rot);
}
#endif

static void triatomat(float *v1, float *v2, float *v3, float (*uv)[2], float mat[][4])
{
    float det, w1, w2, d1[2], d2[2];

    memset(mat, 0, sizeof(float)*4*4);
    mat[3][3]= 1.0f;

    /* first axis is the normal */
    normal_tri_v3( mat[2],v1, v2, v3);

    /* second axis along (1, 0) in uv space */
    if(uv) {
        d1[0]= uv[1][0] - uv[0][0];
        d1[1]= uv[1][1] - uv[0][1];
        d2[0]= uv[2][0] - uv[0][0];
        d2[1]= uv[2][1] - uv[0][1];

        det = d2[0]*d1[1] - d2[1]*d1[0];

        if(det != 0.0f) {
            det= 1.0f/det;
            w1= -d2[1]*det;
            w2= d1[1]*det;

            mat[1][0]= w1*(v2[0] - v1[0]) + w2*(v3[0] - v1[0]);
            mat[1][1]= w1*(v2[1] - v1[1]) + w2*(v3[1] - v1[1]);
            mat[1][2]= w1*(v2[2] - v1[2]) + w2*(v3[2] - v1[2]);
            normalize_v3(mat[1]);
        }
        else
            mat[1][0]= mat[1][1]= mat[1][2]= 0.0f;
    }
    else {
        sub_v3_v3v3(mat[1], v2, v1);
        normalize_v3(mat[1]);
    }
    
    /* third as a cross product */
    cross_v3_v3v3(mat[0], mat[1], mat[2]);
}

static void psys_face_mat(Object *ob, DerivedMesh *dm, ParticleData *pa, float mat[][4], int orco)
{
    float v[3][3];
    MFace *mface;
    OrigSpaceFace *osface;
    float (*orcodata)[3];

    int i = pa->num_dmcache==DMCACHE_NOTFOUND ? pa->num : pa->num_dmcache;
    
    if (i==-1 || i >= dm->getNumFaces(dm)) { unit_m4(mat); return; }

    mface=dm->getFaceData(dm,i,CD_MFACE);
    osface=dm->getFaceData(dm,i,CD_ORIGSPACE);
    
    if(orco && (orcodata=dm->getVertDataArray(dm, CD_ORCO))) {
        copy_v3_v3(v[0], orcodata[mface->v1]);
        copy_v3_v3(v[1], orcodata[mface->v2]);
        copy_v3_v3(v[2], orcodata[mface->v3]);

        /* ugly hack to use non-transformed orcos, since only those
         * give symmetric results for mirroring in particle mode */
        if(DM_get_vert_data_layer(dm, CD_ORIGINDEX))
            transform_mesh_orco_verts(ob->data, v, 3, 1);
    }
    else {
        dm->getVertCo(dm,mface->v1,v[0]);
        dm->getVertCo(dm,mface->v2,v[1]);
        dm->getVertCo(dm,mface->v3,v[2]);
    }

    triatomat(v[0], v[1], v[2], (osface)? osface->uv: NULL, mat);
}

void psys_mat_hair_to_object(Object *UNUSED(ob), DerivedMesh *dm, short from, ParticleData *pa, float hairmat[][4])
{
    float vec[3];

    psys_face_mat(0, dm, pa, hairmat, 0);
    psys_particle_on_dm(dm, from, pa->num, pa->num_dmcache, pa->fuv, pa->foffset, vec, 0, 0, 0, 0, 0);
    copy_v3_v3(hairmat[3],vec);
}

void psys_mat_hair_to_orco(Object *ob, DerivedMesh *dm, short from, ParticleData *pa, float hairmat[][4])
{
    float vec[3], orco[3];

    psys_face_mat(ob, dm, pa, hairmat, 1);
    psys_particle_on_dm(dm, from, pa->num, pa->num_dmcache, pa->fuv, pa->foffset, vec, 0, 0, 0, orco, 0);

    /* see psys_face_mat for why this function is called */
    if(DM_get_vert_data_layer(dm, CD_ORIGINDEX))
        transform_mesh_orco_verts(ob->data, &orco, 1, 1);
    copy_v3_v3(hairmat[3],orco);
}

void psys_vec_rot_to_face(DerivedMesh *dm, ParticleData *pa, float *vec)
{
    float mat[4][4];

    psys_face_mat(0, dm, pa, mat, 0);
    transpose_m4(mat); /* cheap inverse for rotation matrix */
    mul_mat3_m4_v3(mat, vec);
}

void psys_mat_hair_to_global(Object *ob, DerivedMesh *dm, short from, ParticleData *pa, float hairmat[][4])
{
    float facemat[4][4];

    psys_mat_hair_to_object(ob, dm, from, pa, facemat);

    mult_m4_m4m4(hairmat, ob->obmat, facemat);
}

/************************************************/
/*          ParticleSettings handling           */
/************************************************/
ModifierData *object_add_particle_system(Scene *scene, Object *ob, const char *name)
{
    ParticleSystem *psys;
    ModifierData *md;
    ParticleSystemModifierData *psmd;

    if(!ob || ob->type != OB_MESH)
        return NULL;

    psys = ob->particlesystem.first;
    for(; psys; psys=psys->next)
        psys->flag &= ~PSYS_CURRENT;

    psys = MEM_callocN(sizeof(ParticleSystem), "particle_system");
    psys->pointcache = BKE_ptcache_add(&psys->ptcaches);
    BLI_addtail(&ob->particlesystem, psys);

    psys->part = psys_new_settings("ParticleSettings", NULL);

    if(BLI_countlist(&ob->particlesystem)>1)
        BLI_snprintf(psys->name, sizeof(psys->name), "ParticleSystem %i", BLI_countlist(&ob->particlesystem));
    else
        strcpy(psys->name, "ParticleSystem");

    md= modifier_new(eModifierType_ParticleSystem);

    if(name)    BLI_strncpy(md->name, name, sizeof(md->name));
    else        BLI_snprintf(md->name, sizeof(md->name), "ParticleSystem %i", BLI_countlist(&ob->particlesystem));
    modifier_unique_name(&ob->modifiers, md);

    psmd= (ParticleSystemModifierData*) md;
    psmd->psys=psys;
    BLI_addtail(&ob->modifiers, md);

    psys->totpart=0;
    psys->flag = PSYS_ENABLED|PSYS_CURRENT;
    psys->cfra = BKE_frame_to_ctime(scene, CFRA + 1);

    DAG_scene_sort(G.main, scene);
    DAG_id_tag_update(&ob->id, OB_RECALC_DATA);

    return md;
}
void object_remove_particle_system(Scene *scene, Object *ob)
{
    ParticleSystem *psys = psys_get_current(ob);
    ParticleSystemModifierData *psmd;
    ModifierData *md;

    if(!psys)
        return;

    /* clear all other appearances of this pointer (like on smoke flow modifier) */
    if((md = modifiers_findByType(ob, eModifierType_Smoke)))
    {
        SmokeModifierData *smd = (SmokeModifierData *)md;
        if((smd->type == MOD_SMOKE_TYPE_FLOW) && smd->flow && smd->flow->psys)
            if(smd->flow->psys == psys)
                smd->flow->psys = NULL;
    }

    if((md = modifiers_findByType(ob, eModifierType_DynamicPaint)))
    {
        DynamicPaintModifierData *pmd = (DynamicPaintModifierData *)md;
        if(pmd->brush && pmd->brush->psys)
            if(pmd->brush->psys == psys)
                pmd->brush->psys = NULL;
    }

    /* clear modifier */
    psmd= psys_get_modifier(ob, psys);
    BLI_remlink(&ob->modifiers, psmd);
    modifier_free((ModifierData *)psmd);

    /* clear particle system */
    BLI_remlink(&ob->particlesystem, psys);
    psys_free(ob,psys);

    if(ob->particlesystem.first)
        ((ParticleSystem *) ob->particlesystem.first)->flag |= PSYS_CURRENT;
    else
        ob->mode &= ~OB_MODE_PARTICLE_EDIT;

    DAG_scene_sort(G.main, scene);
    DAG_id_tag_update(&ob->id, OB_RECALC_DATA);
}
static void default_particle_settings(ParticleSettings *part)
{
    part->type= PART_EMITTER;
    part->distr= PART_DISTR_JIT;
    part->draw_as = PART_DRAW_REND;
    part->ren_as = PART_DRAW_HALO;
    part->bb_uv_split=1;
    part->bb_align=PART_BB_VIEW;
    part->bb_split_offset=PART_BB_OFF_LINEAR;
    part->flag=PART_EDISTR|PART_TRAND|PART_HIDE_ADVANCED_HAIR;

    part->sta= 1.0;
    part->end= 200.0;
    part->lifetime= 50.0;
    part->jitfac= 1.0;
    part->totpart= 1000;
    part->grid_res= 10;
    part->timetweak= 1.0;
    part->courant_target = 0.2;
    
    part->integrator= PART_INT_MIDPOINT;
    part->phystype= PART_PHYS_NEWTON;
    part->hair_step= 5;
    part->keys_step= 5;
    part->draw_step= 2;
    part->ren_step= 3;
    part->adapt_angle= 5;
    part->adapt_pix= 3;
    part->kink_axis= 2;
    part->kink_amp_clump= 1.f;
    part->reactevent= PART_EVENT_DEATH;
    part->disp=100;
    part->from= PART_FROM_FACE;

    part->normfac= 1.0f;

    part->mass=1.0;
    part->size=0.05;
    part->childsize=1.0;

    part->rotmode = PART_ROT_VEL;
    part->avemode = PART_AVE_SPIN;

    part->child_nbr=10;
    part->ren_child_nbr=100;
    part->childrad=0.2f;
    part->childflat=0.0f;
    part->clumppow=0.0f;
    part->kink_amp=0.2f;
    part->kink_freq=2.0;

    part->rough1_size=1.0;
    part->rough2_size=1.0;
    part->rough_end_shape=1.0;

    part->clength=1.0f;
    part->clength_thres=0.0f;

    part->draw= PART_DRAW_EMITTER;
    part->draw_line[0]=0.5;
    part->path_start = 0.0f;
    part->path_end = 1.0f;

    part->bb_size[0] = part->bb_size[1] = 1.0f;

    part->keyed_loops = 1;

    part->color_vec_max = 1.f;
    part->draw_col = PART_DRAW_COL_MAT;

    part->simplify_refsize= 1920;
    part->simplify_rate= 1.0f;
    part->simplify_transition= 0.1f;
    part->simplify_viewport= 0.8;

    if(!part->effector_weights)
        part->effector_weights = BKE_add_effector_weights(NULL);
}


ParticleSettings *psys_new_settings(const char *name, Main *main)
{
    ParticleSettings *part;

    if(main==NULL)
        main = G.main;

    part= alloc_libblock(&main->particle, ID_PA, name);
    
    default_particle_settings(part);

    return part;
}

ParticleSettings *psys_copy_settings(ParticleSettings *part)
{
    ParticleSettings *partn;
    int a;

    partn= copy_libblock(&part->id);
    partn->pd= MEM_dupallocN(part->pd);
    partn->pd2= MEM_dupallocN(part->pd2);
    partn->effector_weights= MEM_dupallocN(part->effector_weights);
    partn->fluid= MEM_dupallocN(part->fluid);

    partn->boids = boid_copy_settings(part->boids);

    for(a=0; a<MAX_MTEX; a++) {
        if(part->mtex[a]) {
            partn->mtex[a]= MEM_mallocN(sizeof(MTex), "psys_copy_tex");
            memcpy(partn->mtex[a], part->mtex[a], sizeof(MTex));
            id_us_plus((ID *)partn->mtex[a]->tex);
        }
    }

    BLI_duplicatelist(&partn->dupliweights, &part->dupliweights);
    
    return partn;
}

static void expand_local_particlesettings(ParticleSettings *part)
{
    int i;
    id_lib_extern((ID *)part->dup_group);

    for(i=0; i<MAX_MTEX; i++) {
        if(part->mtex[i]) id_lib_extern((ID *)part->mtex[i]->tex);
    }
}

void make_local_particlesettings(ParticleSettings *part)
{
    Main *bmain= G.main;
    Object *ob;
    int is_local= FALSE, is_lib= FALSE;

    /* - only lib users: do nothing
     * - only local users: set flag
     * - mixed: make copy
     */
    
    if(part->id.lib==0) return;
    if(part->id.us==1) {
        id_clear_lib_data(bmain, &part->id);
        expand_local_particlesettings(part);
        return;
    }

    /* test objects */
    for(ob= bmain->object.first; ob && ELEM(FALSE, is_lib, is_local); ob= ob->id.next) {
        ParticleSystem *psys=ob->particlesystem.first;
        for(; psys; psys=psys->next){
            if(psys->part==part) {
                if(ob->id.lib) is_lib= TRUE;
                else is_local= TRUE;
            }
        }
    }
    
    if(is_local && is_lib==FALSE) {
        id_clear_lib_data(bmain, &part->id);
        expand_local_particlesettings(part);
    }
    else if(is_local && is_lib) {
        ParticleSettings *part_new= psys_copy_settings(part);

        part_new->id.us= 0;

        /* Remap paths of new ID using old library as base. */
        BKE_id_lib_local_paths(bmain, part->id.lib, &part_new->id);

        /* do objects */
        for(ob= bmain->object.first; ob; ob= ob->id.next) {
            ParticleSystem *psys;
            for(psys= ob->particlesystem.first; psys; psys=psys->next){
                if(psys->part==part && ob->id.lib==0) {
                    psys->part= part_new;
                    part_new->id.us++;
                    part->id.us--;
                }
            }
        }
    }
}

/************************************************/
/*          Textures                            */
/************************************************/

static int get_particle_uv(DerivedMesh *dm, ParticleData *pa, int face_index, const float fuv[4], char *name, float *texco)
{
    MFace *mf;
    MTFace *tf;
    int i;
    
    tf= CustomData_get_layer_named(&dm->faceData, CD_MTFACE, name);

    if(tf == NULL)
        tf= CustomData_get_layer(&dm->faceData, CD_MTFACE);

    if(tf == NULL)
        return 0;

    if(pa) {
        i= (pa->num_dmcache==DMCACHE_NOTFOUND)? pa->num: pa->num_dmcache;
        if(i >= dm->getNumFaces(dm))
            i = -1;
    }
    else
        i= face_index;

    if (i==-1) {
        texco[0]= 0.0f;
        texco[1]= 0.0f;
        texco[2]= 0.0f;
    }
    else {
        mf= dm->getFaceData(dm, i, CD_MFACE);

        psys_interpolate_uvs(&tf[i], mf->v4, fuv, texco);

        texco[0]= texco[0]*2.0f - 1.0f;
        texco[1]= texco[1]*2.0f - 1.0f;
        texco[2]= 0.0f;
    }

    return 1;
}

#define SET_PARTICLE_TEXTURE(type, pvalue, texfac) if((event & mtex->mapto) & type) {pvalue = texture_value_blend(def, pvalue, value, texfac, blend);}
#define CLAMP_PARTICLE_TEXTURE_POS(type, pvalue) if(event & type) { if(pvalue < 0.f) pvalue = 1.f+pvalue; CLAMP(pvalue, 0.0f, 1.0f); }
#define CLAMP_PARTICLE_TEXTURE_POSNEG(type, pvalue) if(event & type) { CLAMP(pvalue, -1.0f, 1.0f); }

static void get_cpa_texture(DerivedMesh *dm, ParticleSystem *psys, ParticleSettings *part, ParticleData *par, int child_index, int face_index, const float fw[4], float *orco, ParticleTexture *ptex, int event, float cfra)
{
    MTex *mtex, **mtexp = part->mtex;
    int m;
    float value, rgba[4], texvec[3];

    ptex->ivel = ptex->life = ptex->exist = ptex->size = ptex->damp =
        ptex->gravity = ptex->field = ptex->time = ptex->clump = ptex->kink =
        ptex->effector = ptex->rough1 = ptex->rough2 = ptex->roughe = 1.f;

    ptex->length= 1.0f - part->randlength * PSYS_FRAND(child_index + 26);
    ptex->length*= part->clength_thres < PSYS_FRAND(child_index + 27) ? part->clength : 1.0f;

    for(m=0; m<MAX_MTEX; m++, mtexp++){
        mtex = *mtexp;
        if(mtex && mtex->mapto){
            float def=mtex->def_var;
            short blend=mtex->blendtype;
            short texco = mtex->texco;

            if(ELEM(texco, TEXCO_UV, TEXCO_ORCO) && (ELEM(part->from, PART_FROM_FACE, PART_FROM_VOLUME) == 0 || part->distr == PART_DISTR_GRID))
                texco = TEXCO_GLOB;

            switch(texco) {
            case TEXCO_GLOB:
                copy_v3_v3(texvec, par->state.co);
                break;
            case TEXCO_OBJECT:
                copy_v3_v3(texvec, par->state.co);
                if(mtex->object)
                    mul_m4_v3(mtex->object->imat, texvec);
                break;
            case TEXCO_UV:
                if(fw && get_particle_uv(dm, NULL, face_index, fw, mtex->uvname, texvec))
                    break;
                /* no break, failed to get uv's, so let's try orco's */
            case TEXCO_ORCO:
                copy_v3_v3(texvec, orco);
                break;
            case TEXCO_PARTICLE:
                /* texture coordinates in range [-1,1] */
                texvec[0] = 2.f * (cfra - par->time)/(par->dietime-par->time) - 1.f;
                texvec[1] = 0.f;
                texvec[2] = 0.f;
                break;
            }

            externtex(mtex, texvec, &value, rgba, rgba+1, rgba+2, rgba+3, 0);

            if((event & mtex->mapto) & PAMAP_ROUGH)
                ptex->rough1= ptex->rough2= ptex->roughe= texture_value_blend(def,ptex->rough1,value,mtex->roughfac,blend);

            SET_PARTICLE_TEXTURE(PAMAP_LENGTH, ptex->length, mtex->lengthfac);
            SET_PARTICLE_TEXTURE(PAMAP_CLUMP, ptex->clump, mtex->clumpfac);
            SET_PARTICLE_TEXTURE(PAMAP_KINK, ptex->kink, mtex->kinkfac);
            SET_PARTICLE_TEXTURE(PAMAP_DENS, ptex->exist, mtex->padensfac);
        }
    }

    CLAMP_PARTICLE_TEXTURE_POS(PAMAP_LENGTH, ptex->length);
    CLAMP_PARTICLE_TEXTURE_POS(PAMAP_CLUMP, ptex->clump);
    CLAMP_PARTICLE_TEXTURE_POS(PAMAP_KINK, ptex->kink);
    CLAMP_PARTICLE_TEXTURE_POS(PAMAP_ROUGH, ptex->rough1);
    CLAMP_PARTICLE_TEXTURE_POS(PAMAP_DENS, ptex->exist);
}
void psys_get_texture(ParticleSimulationData *sim, ParticleData *pa, ParticleTexture *ptex, int event, float cfra)
{
    ParticleSettings *part = sim->psys->part;
    MTex **mtexp = part->mtex;
    MTex *mtex;
    int m;
    float value, rgba[4], co[3], texvec[3];
    int setvars=0;

    /* initialize ptex */
    ptex->ivel = ptex->life = ptex->exist = ptex->size = ptex->damp =
        ptex->gravity = ptex->field = ptex->length = ptex->clump = ptex->kink =
        ptex->effector = ptex->rough1 = ptex->rough2 = ptex->roughe = 1.f;

    ptex->time = (float)(pa - sim->psys->particles)/(float)sim->psys->totpart;

    for(m=0; m<MAX_MTEX; m++, mtexp++){
        mtex = *mtexp;
        if(mtex && mtex->mapto){
            float def=mtex->def_var;
            short blend=mtex->blendtype;
            short texco = mtex->texco;

            if(texco == TEXCO_UV && (ELEM(part->from, PART_FROM_FACE, PART_FROM_VOLUME) == 0 || part->distr == PART_DISTR_GRID))
                texco = TEXCO_GLOB;

            switch(texco) {
            case TEXCO_GLOB:
                copy_v3_v3(texvec, pa->state.co);
                break;
            case TEXCO_OBJECT:
                copy_v3_v3(texvec, pa->state.co);
                if(mtex->object)
                    mul_m4_v3(mtex->object->imat, texvec);
                break;
            case TEXCO_UV:
                if(get_particle_uv(sim->psmd->dm, pa, 0, pa->fuv, mtex->uvname, texvec))
                    break;
                /* no break, failed to get uv's, so let's try orco's */
            case TEXCO_ORCO:
                psys_particle_on_emitter(sim->psmd,sim->psys->part->from,pa->num,pa->num_dmcache,pa->fuv,pa->foffset,co,0,0,0,texvec, 0);
                break;
            case TEXCO_PARTICLE:
                /* texture coordinates in range [-1,1] */
                texvec[0] = 2.f * (cfra - pa->time)/(pa->dietime-pa->time) - 1.f;
                texvec[1] = 0.f;
                texvec[2] = 0.f;
                break;
            }

            externtex(mtex, texvec, &value, rgba, rgba+1, rgba+2, rgba+3, 0);

            if((event & mtex->mapto) & PAMAP_TIME) {
                /* the first time has to set the base value for time regardless of blend mode */
                if((setvars&MAP_PA_TIME)==0){
                    int flip= (mtex->timefac < 0.0f);
                    float timefac= fabsf(mtex->timefac);
                    ptex->time *= 1.0f - timefac;
                    ptex->time += timefac * ((flip)? 1.0f - value : value);
                    setvars |= MAP_PA_TIME;
                }
                else
                    ptex->time= texture_value_blend(def,ptex->time,value,mtex->timefac,blend);
            }
            SET_PARTICLE_TEXTURE(PAMAP_LIFE, ptex->life, mtex->lifefac)
            SET_PARTICLE_TEXTURE(PAMAP_DENS, ptex->exist, mtex->padensfac)
            SET_PARTICLE_TEXTURE(PAMAP_SIZE, ptex->size, mtex->sizefac)
            SET_PARTICLE_TEXTURE(PAMAP_IVEL, ptex->ivel, mtex->ivelfac)
            SET_PARTICLE_TEXTURE(PAMAP_FIELD, ptex->field, mtex->fieldfac)
            SET_PARTICLE_TEXTURE(PAMAP_GRAVITY, ptex->gravity, mtex->gravityfac)
            SET_PARTICLE_TEXTURE(PAMAP_DAMP, ptex->damp, mtex->dampfac)
            SET_PARTICLE_TEXTURE(PAMAP_LENGTH, ptex->length, mtex->lengthfac)
        }
    }

    CLAMP_PARTICLE_TEXTURE_POS(PAMAP_TIME, ptex->time)
    CLAMP_PARTICLE_TEXTURE_POS(PAMAP_LIFE, ptex->life)
    CLAMP_PARTICLE_TEXTURE_POS(PAMAP_DENS, ptex->exist)
    CLAMP_PARTICLE_TEXTURE_POS(PAMAP_SIZE, ptex->size)
    CLAMP_PARTICLE_TEXTURE_POSNEG(PAMAP_IVEL, ptex->ivel)
    CLAMP_PARTICLE_TEXTURE_POSNEG(PAMAP_FIELD, ptex->field)
    CLAMP_PARTICLE_TEXTURE_POSNEG(PAMAP_GRAVITY, ptex->gravity)
    CLAMP_PARTICLE_TEXTURE_POS(PAMAP_DAMP, ptex->damp)
    CLAMP_PARTICLE_TEXTURE_POS(PAMAP_LENGTH, ptex->length)
}
/************************************************/
/*          Particle State                      */
/************************************************/
float psys_get_timestep(ParticleSimulationData *sim)
{
    return 0.04f * sim->psys->part->timetweak;
}
float psys_get_child_time(ParticleSystem *psys, ChildParticle *cpa, float cfra, float *birthtime, float *dietime)
{
    ParticleSettings *part = psys->part;
    float time, life;

    if(part->childtype==PART_CHILD_FACES){
        int w=0;
        time=0.0;
        while(w<4 && cpa->pa[w]>=0){
            time+=cpa->w[w]*(psys->particles+cpa->pa[w])->time;
            w++;
        }

        life = part->lifetime * (1.0f - part->randlife * PSYS_FRAND(cpa - psys->child + 25));
    }
    else{
        ParticleData *pa = psys->particles + cpa->parent;

        time = pa->time;
        life = pa->lifetime;
    }

    if(birthtime)
        *birthtime = time;
    if(dietime)
        *dietime = time+life;

    return (cfra-time)/life;
}
float psys_get_child_size(ParticleSystem *psys, ChildParticle *cpa, float UNUSED(cfra), float *UNUSED(pa_time))
{
    ParticleSettings *part = psys->part;
    float size; // time XXX
    
    if(part->childtype==PART_CHILD_FACES)
        size=part->size;
    else
        size=psys->particles[cpa->parent].size;

    size*=part->childsize;

    if(part->childrandsize != 0.0f)
        size *= 1.0f - part->childrandsize * PSYS_FRAND(cpa - psys->child + 26);

    return size;
}
static void get_child_modifier_parameters(ParticleSettings *part, ParticleThreadContext *ctx, ChildParticle *cpa, short cpa_from, int cpa_num, float *cpa_fuv, float *orco, ParticleTexture *ptex)
{
    ParticleSystem *psys = ctx->sim.psys;
    int i = cpa - psys->child;

    get_cpa_texture(ctx->dm, psys, part, psys->particles + cpa->pa[0], i, cpa_num, cpa_fuv, orco, ptex, PAMAP_DENS|PAMAP_CHILD, psys->cfra);


    if(ptex->exist < PSYS_FRAND(i + 24))
        return;

    if(ctx->vg_length)
        ptex->length*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_length);
    if(ctx->vg_clump)
        ptex->clump*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_clump);
    if(ctx->vg_kink)
        ptex->kink*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_kink);
    if(ctx->vg_rough1)
        ptex->rough1*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_rough1);
    if(ctx->vg_rough2)
        ptex->rough2*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_rough2);
    if(ctx->vg_roughe)
        ptex->roughe*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_roughe);
    if(ctx->vg_effector)
        ptex->effector*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_effector);
}
static void do_child_modifiers(ParticleSimulationData *sim, ParticleTexture *ptex, ParticleKey *par, float *par_rot, ChildParticle *cpa, float *orco, float mat[4][4], ParticleKey *state, float t)
{
    ParticleSettings *part = sim->psys->part;
    int i = cpa - sim->psys->child;
    int guided = 0;

    float kink_freq = part->kink_freq;
    float rough1 = part->rough1;
    float rough2 = part->rough2;
    float rough_end = part->rough_end;

    if(ptex) {
        kink_freq *= ptex->kink;
        rough1 *= ptex->rough1;
        rough2 *= ptex->rough2;
        rough_end *= ptex->roughe;
    }

    if(part->flag & PART_CHILD_EFFECT)
        /* state is safe to cast, since only co and vel are used */
        guided = do_guides(sim->psys->effectors, (ParticleKey*)state, cpa->parent, t);

    if(guided==0){
        float clump = do_clump(state, par, t, part->clumpfac, part->clumppow, ptex ? ptex->clump : 1.f);

        if(kink_freq != 0.f) {
            float kink_amp = part->kink_amp * (1.f - part->kink_amp_clump * clump);

            do_kink(state, par, par_rot, t, kink_freq, part->kink_shape,
                    kink_amp, part->kink_flat, part->kink, part->kink_axis,
                    sim->ob->obmat, sim->psys->part->childtype == PART_CHILD_FACES);
        }
    }

    if(rough1 > 0.f)
        do_rough(orco, mat, t, rough1, part->rough1_size, 0.0, state);

    if(rough2 > 0.f)
        do_rough(sim->psys->frand + ((i + 27) % (PSYS_FRAND_COUNT - 3)), mat, t, rough2, part->rough2_size, part->rough2_thres, state);

    if(rough_end > 0.f)
        do_rough_end(sim->psys->frand + ((i + 27) % (PSYS_FRAND_COUNT - 3)), mat, t, rough_end, part->rough_end_shape, state);
}
/* get's hair (or keyed) particles state at the "path time" specified in state->time */
void psys_get_particle_on_path(ParticleSimulationData *sim, int p, ParticleKey *state, int vel)
{
    PARTICLE_PSMD;
    ParticleSystem *psys = sim->psys;
    ParticleSettings *part = sim->psys->part;
    Material *ma = give_current_material(sim->ob, part->omat);
    ParticleData *pa;
    ChildParticle *cpa;
    ParticleTexture ptex;
    ParticleKey *par=0, keys[4], tstate;
    ParticleThreadContext ctx; /* fake thread context for child modifiers */
    ParticleInterpolationData pind;

    float t;
    float co[3], orco[3];
    float hairmat[4][4];
    int totpart = psys->totpart;
    int totchild = psys->totchild;
    short between = 0, edit = 0;

    int keyed = part->phystype & PART_PHYS_KEYED && psys->flag & PSYS_KEYED;
    int cached = !keyed && part->type != PART_HAIR;

    float *cpa_fuv; int cpa_num; short cpa_from;

    /* initialize keys to zero */
    memset(keys, 0, 4*sizeof(ParticleKey));

    t=state->time;
    CLAMP(t, 0.0f, 1.0f);

    if(p<totpart){
        pa = psys->particles + p;
        pind.keyed = keyed;
        pind.cache = cached ? psys->pointcache : NULL;
        pind.epoint = NULL;
        pind.bspline = (psys->part->flag & PART_HAIR_BSPLINE);
        /* pind.dm disabled in editmode means we dont get effectors taken into
         * account when subdividing for instance */
        pind.dm = psys_in_edit_mode(sim->scene, psys) ? NULL : psys->hair_out_dm;
        init_particle_interpolation(sim->ob, psys, pa, &pind);
        do_particle_interpolation(psys, p, pa, t, &pind, state);

        if(pind.dm) {
            mul_m4_v3(sim->ob->obmat, state->co);
            mul_mat3_m4_v3(sim->ob->obmat, state->vel);
        }
        else if(!keyed && !cached && !(psys->flag & PSYS_GLOBAL_HAIR)) {
            if((pa->flag & PARS_REKEY)==0) {
                psys_mat_hair_to_global(sim->ob, sim->psmd->dm, part->from, pa, hairmat);
                mul_m4_v3(hairmat, state->co);
                mul_mat3_m4_v3(hairmat, state->vel);

                if(sim->psys->effectors && (part->flag & PART_CHILD_GUIDE)==0) {
                    do_guides(sim->psys->effectors, state, p, state->time);
                    /* TODO: proper velocity handling */
                }

                if(psys->lattice && edit==0)
                    calc_latt_deform(psys->lattice, state->co,1.0f);
            }
        }
    }
    else if(totchild){
        //invert_m4_m4(imat,ob->obmat);

        cpa=psys->child+p-totpart;

        if(state->time < 0.0f)
            t = psys_get_child_time(psys, cpa, -state->time, NULL, NULL);
        
        if(totchild && part->childtype==PART_CHILD_FACES){
            /* part->parents could still be 0 so we can't test with totparent */
            between=1;
        }
        if(between){
            int w = 0;
            float foffset;

            /* get parent states */
            while(w<4 && cpa->pa[w]>=0){
                keys[w].time = state->time;
                psys_get_particle_on_path(sim, cpa->pa[w], keys+w, 1);
                w++;
            }

            /* get the original coordinates (orco) for texture usage */
            cpa_num=cpa->num;
            
            foffset= cpa->foffset;
            cpa_fuv = cpa->fuv;
            cpa_from = PART_FROM_FACE;

            psys_particle_on_emitter(psmd,cpa_from,cpa_num,DMCACHE_ISCHILD,cpa->fuv,foffset,co,0,0,0,orco,0);

            /* we need to save the actual root position of the child for positioning it accurately to the surface of the emitter */
            //copy_v3_v3(cpa_1st,co);

            //mul_m4_v3(ob->obmat,cpa_1st);

            pa = psys->particles + cpa->parent;

            if(part->type == PART_HAIR)
                psys_mat_hair_to_global(sim->ob, sim->psmd->dm, psys->part->from, pa, hairmat);
            else
                unit_m4(hairmat);

            pa=0;
        }
        else{
            /* get the parent state */
            keys->time = state->time;
            psys_get_particle_on_path(sim, cpa->parent, keys,1);

            /* get the original coordinates (orco) for texture usage */
            pa=psys->particles+cpa->parent;

            cpa_from=part->from;
            cpa_num=pa->num;
            cpa_fuv=pa->fuv;

            

            if(part->type == PART_HAIR) {
                psys_particle_on_emitter(psmd,cpa_from,cpa_num,DMCACHE_ISCHILD,cpa_fuv,pa->foffset,co,0,0,0,orco,0);
                psys_mat_hair_to_global(sim->ob, sim->psmd->dm, psys->part->from, pa, hairmat);
            }
            else {
                copy_v3_v3(orco, cpa->fuv);
                unit_m4(hairmat);
            }
        }

        /* correct child ipo timing */
#if 0 // XXX old animation system
        if((part->flag&PART_ABS_TIME)==0 && part->ipo){
            calc_ipo(part->ipo, 100.0f*t);
            execute_ipo((ID *)part, part->ipo);
        }
#endif // XXX old animation system
        
        /* get different child parameters from textures & vgroups */
        memset(&ctx, 0, sizeof(ParticleThreadContext));
        ctx.sim = *sim;
        ctx.dm = psmd->dm;
        ctx.ma = ma;
        /* TODO: assign vertex groups */
        get_child_modifier_parameters(part, &ctx, cpa, cpa_from, cpa_num, cpa_fuv, orco, &ptex);

        if(between){
            int w=0;

            state->co[0] = state->co[1] = state->co[2] = 0.0f;
            state->vel[0] = state->vel[1] = state->vel[2] = 0.0f;

            /* child position is the weighted sum of parent positions */
            while(w<4 && cpa->pa[w]>=0){
                state->co[0] += cpa->w[w] * keys[w].co[0];
                state->co[1] += cpa->w[w] * keys[w].co[1];
                state->co[2] += cpa->w[w] * keys[w].co[2];

                state->vel[0] += cpa->w[w] * keys[w].vel[0];
                state->vel[1] += cpa->w[w] * keys[w].vel[1];
                state->vel[2] += cpa->w[w] * keys[w].vel[2];
                w++;
            }
            /* apply offset for correct positioning */
            //add_v3_v3(state->co, cpa_1st);
        }
        else{
            /* offset the child from the parent position */
            offset_child(cpa, keys, keys->rot, state, part->childflat, part->childrad);
        }

        par = keys;

        if(vel)
            copy_particle_key(&tstate, state, 1);

        /* apply different deformations to the child path */
        do_child_modifiers(sim, &ptex, par, par->rot, cpa, orco, hairmat, state, t);

        /* try to estimate correct velocity */
        if(vel){
            ParticleKey tstate;
            float length = len_v3(state->vel);

            if(t>=0.001f){
                tstate.time=t-0.001f;
                psys_get_particle_on_path(sim,p,&tstate,0);
                sub_v3_v3v3(state->vel,state->co,tstate.co);
                normalize_v3(state->vel);
            }
            else{
                tstate.time=t+0.001f;
                psys_get_particle_on_path(sim,p,&tstate,0);
                sub_v3_v3v3(state->vel,tstate.co,state->co);
                normalize_v3(state->vel);
            }

            mul_v3_fl(state->vel, length);
        }
    }
}
/* gets particle's state at a time, returns 1 if particle exists and can be seen and 0 if not */
int psys_get_particle_state(ParticleSimulationData *sim, int p, ParticleKey *state, int always)
{
    ParticleSystem *psys = sim->psys;
    ParticleSettings *part = psys->part;
    ParticleData *pa = NULL;
    ChildParticle *cpa = NULL;
    float cfra;
    int totpart = psys->totpart;
    float timestep = psys_get_timestep(sim);

    /* negative time means "use current time" */
    cfra = state->time > 0 ? state->time : BKE_curframe(sim->scene);

    if(p>=totpart){
        if(!psys->totchild)
            return 0;

        if(part->childtype == PART_CHILD_FACES){
            if(!(psys->flag & PSYS_KEYED))
                return 0;

            cpa = psys->child + p - totpart;

            state->time = psys_get_child_time(psys, cpa, cfra, NULL, NULL);

            if(!always)
                if((state->time < 0.0f && !(part->flag & PART_UNBORN))
                    || (state->time > 1.0f && !(part->flag & PART_DIED)))
                    return 0;

            state->time= (cfra - (part->sta + (part->end - part->sta) * PSYS_FRAND(p + 23))) / (part->lifetime * PSYS_FRAND(p + 24));

            psys_get_particle_on_path(sim, p, state,1);
            return 1;
        }
        else {
            cpa = sim->psys->child + p - totpart;
            pa = sim->psys->particles + cpa->parent;
        }
    }
    else {
        pa = sim->psys->particles + p;
    }

    if(pa) {
        if(!always)
            if((cfra < pa->time && (part->flag & PART_UNBORN)==0)
                || (cfra > pa->dietime && (part->flag & PART_DIED)==0))
                return 0;

        cfra = MIN2(cfra, pa->dietime);
    }

    if(sim->psys->flag & PSYS_KEYED){
        state->time= -cfra;
        psys_get_particle_on_path(sim, p, state,1);
        return 1;
    }
    else{
        if(cpa){
            float mat[4][4];
            ParticleKey *key1;
            float t = (cfra - pa->time) / pa->lifetime;

            key1=&pa->state;
            offset_child(cpa, key1, key1->rot, state, part->childflat, part->childrad);

            CLAMP(t, 0.0f, 1.0f);

            unit_m4(mat);
            do_child_modifiers(sim, NULL, key1, key1->rot, cpa, cpa->fuv, mat, state, t);

            if(psys->lattice)
                calc_latt_deform(sim->psys->lattice, state->co,1.0f);
        }
        else{
            if(pa->state.time==cfra || ELEM(part->phystype,PART_PHYS_NO,PART_PHYS_KEYED))
                copy_particle_key(state, &pa->state, 1);
            else if(pa->prev_state.time==cfra)
                copy_particle_key(state, &pa->prev_state, 1);
            else {
                float dfra, frs_sec = sim->scene->r.frs_sec;
                /* let's interpolate to try to be as accurate as possible */
                if(pa->state.time + 2.f >= state->time && pa->prev_state.time - 2.f <= state->time) {
                    if(pa->prev_state.time >= pa->state.time || pa->prev_state.time < 0.f) {
                        /* prev_state is wrong so let's not use it, this can happen at frames 1, 0 or particle birth */
                        dfra = state->time - pa->state.time;

                        copy_particle_key(state, &pa->state, 1);

                        madd_v3_v3v3fl(state->co, state->co, state->vel, dfra/frs_sec);
                    }
                    else {
                        ParticleKey keys[4];
                        float keytime;

                        copy_particle_key(keys+1, &pa->prev_state, 1);
                        copy_particle_key(keys+2, &pa->state, 1);

                        dfra = keys[2].time - keys[1].time;

                        keytime = (state->time - keys[1].time) / dfra;

                        /* convert velocity to timestep size */
                        mul_v3_fl(keys[1].vel, dfra * timestep);
                        mul_v3_fl(keys[2].vel, dfra * timestep);
                        
                        psys_interpolate_particle(-1, keys, keytime, state, 1);
                        
                        /* convert back to real velocity */
                        mul_v3_fl(state->vel, 1.f / (dfra * timestep));

                        interp_v3_v3v3(state->ave, keys[1].ave, keys[2].ave, keytime);
                        interp_qt_qtqt(state->rot, keys[1].rot, keys[2].rot, keytime);
                    }
                }
                else if(pa->state.time + 1.f >= state->time && pa->state.time - 1.f <= state->time) {
                    /* linear interpolation using only pa->state */

                    dfra = state->time - pa->state.time;

                    copy_particle_key(state, &pa->state, 1);

                    madd_v3_v3v3fl(state->co, state->co, state->vel, dfra/frs_sec);
                }
                else {
                    /* extrapolating over big ranges is not accurate so let's just give something close to reasonable back */
                    copy_particle_key(state, &pa->state, 0);
                }
            }

            if(sim->psys->lattice)
                calc_latt_deform(sim->psys->lattice, state->co,1.0f);
        }
        
        return 1;
    }
}

void psys_get_dupli_texture(ParticleSystem *psys, ParticleSettings *part, ParticleSystemModifierData *psmd, ParticleData *pa, ChildParticle *cpa, float *uv, float *orco)
{
    MFace *mface;
    MTFace *mtface;
    float loc[3];
    int num;

    uv[0] = uv[1] = 0.f;

    if(cpa) {
        if(part->childtype == PART_CHILD_FACES) {
            mtface= CustomData_get_layer(&psmd->dm->faceData, CD_MTFACE);
            if(mtface) {
                mface= psmd->dm->getFaceData(psmd->dm, cpa->num, CD_MFACE);
                mtface += cpa->num;
                psys_interpolate_uvs(mtface, mface->v4, cpa->fuv, uv);
            }
        
            psys_particle_on_emitter(psmd,PART_FROM_FACE,cpa->num,DMCACHE_ISCHILD,cpa->fuv,cpa->foffset,loc,0,0,0,orco,0);
            return;
        }
        else {
            pa = psys->particles + cpa->pa[0];
        }
    }

    if(part->from == PART_FROM_FACE) {
        mtface= CustomData_get_layer(&psmd->dm->faceData, CD_MTFACE);
        num= pa->num_dmcache;

        if(num == DMCACHE_NOTFOUND)
            num= pa->num;

        if (num >= psmd->dm->getNumFaces(psmd->dm)) {
            /* happens when simplify is enabled
                * gives invalid coords but would crash otherwise */
            num= DMCACHE_NOTFOUND;
        }

        if(mtface && num != DMCACHE_NOTFOUND) {
            mface= psmd->dm->getFaceData(psmd->dm, num, CD_MFACE);
            mtface += num;
            psys_interpolate_uvs(mtface, mface->v4, pa->fuv, uv);
        }
    }

    psys_particle_on_emitter(psmd,part->from,pa->num,pa->num_dmcache,pa->fuv,pa->foffset,loc,0,0,0,orco,0);
}

void psys_get_dupli_path_transform(ParticleSimulationData *sim, ParticleData *pa, ChildParticle *cpa, ParticleCacheKey *cache, float mat[][4], float *scale)
{
    Object *ob = sim->ob;
    ParticleSystem *psys = sim->psys;
    ParticleSystemModifierData *psmd = sim->psmd;
    float loc[3], nor[3], vec[3], side[3], len;
    float xvec[3] = {-1.0, 0.0, 0.0}, nmat[3][3];

    sub_v3_v3v3(vec, (cache+cache->steps)->co, cache->co);
    len= normalize_v3(vec);

    if(pa == NULL && psys->part->childflat != PART_CHILD_FACES)
        pa = psys->particles + cpa->pa[0];

    if(pa)
        psys_particle_on_emitter(psmd,sim->psys->part->from,pa->num,pa->num_dmcache,pa->fuv,pa->foffset,loc,nor,0,0,0,0);
    else
        psys_particle_on_emitter(psmd,PART_FROM_FACE,cpa->num,DMCACHE_ISCHILD,cpa->fuv,cpa->foffset,loc,nor,0,0,0,0);

    if(psys->part->rotmode == PART_ROT_VEL) {
        copy_m3_m4(nmat, ob->imat);
        transpose_m3(nmat);
        mul_m3_v3(nmat, nor);
        normalize_v3(nor);

        /* make sure that we get a proper side vector */
        if(fabs(dot_v3v3(nor,vec))>0.999999) {
            if(fabs(dot_v3v3(nor,xvec))>0.999999) {
                nor[0] = 0.0f;
                nor[1] = 1.0f;
                nor[2] = 0.0f;
            }
            else {
                nor[0] = 1.0f;
                nor[1] = 0.0f;
                nor[2] = 0.0f;
            }
        }
        cross_v3_v3v3(side, nor, vec);
        normalize_v3(side);

        /* rotate side vector around vec */
        if(psys->part->phasefac != 0) {
            float q_phase[4];
            float phasefac = psys->part->phasefac;
            if(psys->part->randphasefac != 0.0f)
                phasefac += psys->part->randphasefac * PSYS_FRAND((pa-psys->particles) + 20);
            axis_angle_to_quat( q_phase, vec, phasefac*(float)M_PI);

            mul_qt_v3(q_phase, side);
        }

        cross_v3_v3v3(nor, vec, side);

        unit_m4(mat);
        copy_v3_v3(mat[0], vec);
        copy_v3_v3(mat[1], side);
        copy_v3_v3(mat[2], nor);
    }
    else {
        quat_to_mat4(mat, pa->state.rot);
    }

    *scale= len;
}

void psys_make_billboard(ParticleBillboardData *bb, float xvec[3], float yvec[3], float zvec[3], float center[3])
{
    float onevec[3] = {0.0f,0.0f,0.0f}, tvec[3], tvec2[3];

    xvec[0] = 1.0f; xvec[1] = 0.0f; xvec[2] = 0.0f;
    yvec[0] = 0.0f; yvec[1] = 1.0f; yvec[2] = 0.0f;

    /* can happen with bad pointcache or physics calculation
     * since this becomes geometry, nan's and inf's crash raytrace code.
     * better not allow this. */
    if( !finite(bb->vec[0]) || !finite(bb->vec[1]) || !finite(bb->vec[2]) ||
        !finite(bb->vel[0]) || !finite(bb->vel[1]) || !finite(bb->vel[2]) )
    {
        zero_v3(bb->vec);
        zero_v3(bb->vel);

        zero_v3(xvec);
        zero_v3(yvec);
        zero_v3(zvec);
        zero_v3(center);

        return;
    }

    if(bb->align < PART_BB_VIEW)
        onevec[bb->align]=1.0f;

    if(bb->lock && (bb->align == PART_BB_VIEW)) {
        normalize_v3_v3(xvec, bb->ob->obmat[0]);
        normalize_v3_v3(yvec, bb->ob->obmat[1]);
        normalize_v3_v3(zvec, bb->ob->obmat[2]);
    }
    else if(bb->align == PART_BB_VEL) {
        float temp[3];

        normalize_v3_v3(temp, bb->vel);

        sub_v3_v3v3(zvec, bb->ob->obmat[3], bb->vec);

        if(bb->lock) {
            float fac = -dot_v3v3(zvec, temp);

            madd_v3_v3fl(zvec, temp, fac);
        }
        normalize_v3(zvec);

        cross_v3_v3v3(xvec,temp,zvec);
        normalize_v3(xvec);

        cross_v3_v3v3(yvec,zvec,xvec);
    }
    else {
        sub_v3_v3v3(zvec, bb->ob->obmat[3], bb->vec);
        if(bb->lock)
            zvec[bb->align] = 0.0f;
        normalize_v3(zvec);

        if(bb->align < PART_BB_VIEW)
            cross_v3_v3v3(xvec, onevec, zvec);
        else
            cross_v3_v3v3(xvec, bb->ob->obmat[1], zvec);
        normalize_v3(xvec);

        cross_v3_v3v3(yvec,zvec,xvec);
    }

    copy_v3_v3(tvec, xvec);
    copy_v3_v3(tvec2, yvec);

    mul_v3_fl(xvec, cos(bb->tilt * (float)M_PI));
    mul_v3_fl(tvec2, sin(bb->tilt * (float)M_PI));
    add_v3_v3(xvec, tvec2);

    mul_v3_fl(yvec, cos(bb->tilt * (float)M_PI));
    mul_v3_fl(tvec, -sin(bb->tilt * (float)M_PI));
    add_v3_v3(yvec, tvec);

    mul_v3_fl(xvec, bb->size[0]);
    mul_v3_fl(yvec, bb->size[1]);

    madd_v3_v3v3fl(center, bb->vec, xvec, bb->offset[0]);
    madd_v3_v3fl(center, yvec, bb->offset[1]);
}


void psys_apply_hair_lattice(Scene *scene, Object *ob, ParticleSystem *psys)
{
    ParticleSimulationData sim= {0};
    sim.scene= scene;
    sim.ob= ob;
    sim.psys= psys;
    sim.psmd= psys_get_modifier(ob, psys);

    psys->lattice = psys_get_lattice(&sim);

    if(psys->lattice) {
        ParticleData *pa = psys->particles;
        HairKey *hkey;
        int p, h;
        float hairmat[4][4], imat[4][4];

        for(p=0; p<psys->totpart; p++, pa++) {
            psys_mat_hair_to_global(sim.ob, sim.psmd->dm, psys->part->from, pa, hairmat);
            invert_m4_m4(imat, hairmat);

            hkey = pa->hair;
            for(h=0; h<pa->totkey; h++, hkey++) {
                mul_m4_v3(hairmat, hkey->co);
                calc_latt_deform(psys->lattice, hkey->co, 1.0f);
                mul_m4_v3(imat, hkey->co);
            }
        }
        
        end_latt_deform(psys->lattice);
        psys->lattice= NULL;

        /* protect the applied shape */
        psys->flag |= PSYS_EDITED;
    }
}