git.mutantstargoat.com Git - cyberay/blob - src/geom.c

   1 #include <float.h>
   2 #include "geom.h"
   3
   4 void free_bvh_tree(struct bvhnode *tree)
   5 {
   6         struct bvhnode *node, *tmp;
   7
   8         free(tree->faces);
   9
  10         free_bvh_tree(tree->left);
  11         free_bvh_tree(tree->right);
  12         free(tree);
  13 }
  14
  15 int ray_triangle(cgm_ray *ray, struct triangle *tri, float tmax, struct rayhit *hit)
  16 {
  17         float t, ndotdir;
  18         cgm_vec3 vdir, bc, pos;
  19
  20         if(fabs(ndotdir = cgm_vdot(&ray->dir, &tri->norm)) <= 1e-6) {
  21                 return 0;
  22         }
  23
  24         vdir = tri->v[0].pos;
  25         cgm_vsub(&vdir, &ray->origin);
  26
  27         if((t = cgm_vdot(&tri->norm, &vdir) / ndotdir) <= 1e-6 || t > tmax) {
  28                 return 0;
  29         }
  30
  31         cgm_raypos(&pos, ray, t);
  32         cgm_bary(&bc, &tri->v[0].pos, &tri->v[1].pos, &tri->v[2].pos, &pos);
  33
  34         if(bc.x < 0.0f || bc.x > 1.0f) return 0;
  35         if(bc.y < 0.0f || bc.y > 1.0f) return 0;
  36         if(bc.z < 0.0f || bc.z > 1.0f) return 0;
  37
  38         if(hit) {
  39                 hit->t = t;
  40                 hit->ray = *ray;
  41                 hit->mtl = tri->mtl;
  42
  43                 hit->v.pos = pos;
  44
  45                 hit->v.norm.x = tri->v[0].norm.x * bc.x + tri->v[1].norm.x * bc.y + tri->v[2].norm.x * bc.z;
  46                 hit->v.norm.y = tri->v[0].norm.y * bc.x + tri->v[1].norm.y * bc.y + tri->v[2].norm.y * bc.z;
  47                 hit->v.norm.z = tri->v[0].norm.z * bc.x + tri->v[1].norm.z * bc.y + tri->v[2].norm.z * bc.z;
  48
  49                 hit->v.tex.x = tri->v[0].tex.x * bc.x + tri->v[1].tex.x * bc.y + tri->v[2].tex.x * bc.z;
  50                 hit->v.tex.y = tri->v[0].tex.y * bc.x + tri->v[1].tex.y * bc.y + tri->v[2].tex.y * bc.z;
  51         }
  52         return 1;
  53 }
  54
  55 #define SLABCHECK(dim)  \
  56         do { \
  57                 invdir = 1.0f / ray->dir.dim;   \
  58                 t0 = (box->vmin.dim - ray->origin.dim) * invdir;        \
  59                 t1 = (box->vmax.dim - ray->origin.dim) * invdir;        \
  60                 if(invdir < 0.0f) {     \
  61                         tmp = t0;       \
  62                         t0 = t1;        \
  63                         t1 = tmp;       \
  64                 }       \
  65                 tmin = t0 > tmin ? t0 : tmin;   \
  66                 tmax = t1 < tmax ? t1 : tmax;   \
  67                 if(tmax <= tmin) return 0; \
  68         } while(0)
  69
  70 int ray_aabox_any(cgm_ray *ray, struct aabox *box, float tmax)
  71 {
  72         float invdir, t0, t1, tmp;
  73         float tmin = 0.0f;
  74
  75         SLABCHECK(x);
  76         SLABCHECK(y);
  77         SLABCHECK(z);
  78
  79         return 1;
  80 }
  81
  82 int ray_bvhnode(cgm_ray *ray, struct bvhnode *bn, float tmax, struct rayhit *hit)
  83 {
  84         int i, res = 0;
  85         struct rayhit hit0;
  86
  87         if(!ray_aabox_any(ray, &bn->aabb, tmax)) {
  88                 return 0;
  89         }
  90
  91         if(!hit) {
  92                 for(i=0; i<bn->num_faces; i++) {
  93                         if(ray_triangle(ray, bn->faces + i, tmax, 0)) {
  94                                 return 1;
  95                         }
  96                 }
  97                 return 0;
  98         }
  99
 100         hit0.t = FLT_MAX;
 101         for(i=0; i<bn->num_faces; i++) {
 102                 if(ray_triangle(ray, bn->faces + i, tmax, hit) && hit->t < hit0.t) {
 103                         hit0 = *hit;
 104                         res = 1;
 105                 }
 106         }
 107         *hit = hit0;
 108         return res;
 109 }