rayintersection.h

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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 Blender Foundation.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): André Pinto.
 *
 * ***** END GPL LICENSE BLOCK *****
 * RE_raytrace.h: ray tracing api, can be used independently from the renderer. 
 */

#ifndef __RENDER_RAYINTERSECTION_H__
#define __RENDER_RAYINTERSECTION_H__

#ifdef __cplusplus
extern "C" {
#endif

struct RayObject;

/* Ray Hints */

#define RE_RAY_LCTS_MAX_SIZE    256
#define RT_USE_LAST_HIT         /* last shadow hit is reused before raycasting on whole tree */
//#define RT_USE_HINT           /* last hit object is reused before raycasting on whole tree */

typedef struct LCTSHint {
    int size;
    struct RayObject *stack[RE_RAY_LCTS_MAX_SIZE];
} LCTSHint;

typedef struct RayHint {
    union { LCTSHint lcts; } data;
} RayHint;

/* Ray Intersection */

typedef struct Isect {
    /* ray start, direction (normalized vector), and max distance. on hit,
       the distance is modified to be the distance to the hit point. */
    float start[3];
    float dir[3];
    float dist;

    /* precomputed values to accelerate bounding box intersection */
    int bv_index[6];
    float idot_axis[3];

    /* intersection options */
    int mode;               /* RE_RAY_SHADOW, RE_RAY_MIRROR, RE_RAY_SHADOW_TRA */
    int lay;                /* -1 default, set for layer lamps */
    int skip;               /* skip flags */
    int check;              /* check flags */
    void *userdata;         /* used by bake check */

    /* hit information */
    float u, v;
    int isect;              /* which half of quad */
    
    struct {
        void *ob;
        void *face;
    } hit, orig;
    
    /* last hit optimization */
    struct RayObject *last_hit;

    /* hints */
#ifdef RT_USE_HINT
    RayTraceHint *hint, *hit_hint;
#endif
    RayHint *hint;
    
    /* ray counter */
#ifdef RE_RAYCOUNTER
    RayCounter *raycounter;
#endif
} Isect;

/* ray types */
#define RE_RAY_SHADOW 0
#define RE_RAY_MIRROR 1
#define RE_RAY_SHADOW_TRA 2

/* skip options */
#define RE_SKIP_CULLFACE                (1 << 0)
/* if using this flag then *face should be a pointer to a VlakRen */
#define RE_SKIP_VLR_NEIGHBOUR           (1 << 1)

/* check options */
#define RE_CHECK_VLR_NONE               0
#define RE_CHECK_VLR_RENDER             1
#define RE_CHECK_VLR_NON_SOLID_MATERIAL 2
#define RE_CHECK_VLR_BAKE               3

/* arbitrary, but can't use e.g. FLT_MAX because of precision issues */
#define RE_RAYTRACE_MAXDIST 1e15f
#define RE_RAYTRACE_EPSILON 0.0f

#ifdef __cplusplus
}
#endif

#endif /* __RENDER_RAYINTERSECTION_H__ */