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         node = tree->sub;
  11         while(node) {
  12                 tmp = node;
  13                 node = node->next;
  14                 free_bvh_tree(tmp);
  15         }
  16
  17         free(tree);
  18 }
  19
  20 int ray_triangle(cgm_ray *ray, struct triangle *tri, float tmax, struct rayhit *hit)
  21 {
  22         float t, ndotdir;
  23         cgm_vec3 vdir, bc, pos;
  24
  25         if(fabs(ndotdir = cgm_vdot(&ray->dir, &tri->norm)) <= 1e-6) {
  26                 return 0;
  27         }
  28
  29         vdir = tri->v[0].pos;
  30         cgm_vsub(&vdir, &ray->origin);
  31
  32         if((t = cgm_vdot(&tri->norm, &vdir) / ndotdir) <= 1e-6 || t > tmax) {
  33                 return 0;
  34         }
  35
  36         cgm_raypos(&pos, ray, t);
  37         cgm_bary(&bc, &tri->v[0].pos, &tri->v[1].pos, &tri->v[2].pos, &pos);
  38
  39         if(bc.x < 0.0f || bc.x > 1.0f) return 0;
  40         if(bc.y < 0.0f || bc.y > 1.0f) return 0;
  41         if(bc.z < 0.0f || bc.z > 1.0f) return 0;
  42
  43         if(hit) {
  44                 hit->t = t;
  45                 hit->ray = *ray;
  46                 hit->mtl = tri->mtl;
  47
  48                 hit->v.pos = pos;
  49
  50                 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;
  51                 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;
  52                 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;
  53
  54                 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;
  55                 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;
  56         }
  57         return 1;
  58 }
  59
  60 #define SLABCHECK(dim)  \
  61         do { \
  62                 invdir = 1.0f / ray->dir.dim;   \
  63                 t0 = (box->vmin.dim - ray->origin.dim) * invdir;        \
  64                 t1 = (box->vmax.dim - ray->origin.dim) * invdir;        \
  65                 if(invdir < 0.0f) {     \
  66                         tmp = t0;       \
  67                         t0 = t1;        \
  68                         t1 = tmp;       \
  69                 }       \
  70                 tmin = t0 > tmin ? t0 : tmin;   \
  71                 tmax = t1 < tmax ? t1 : tmax;   \
  72                 if(tmax <= tmin) return 0; \
  73         } while(0)
  74
  75 int ray_aabox_any(cgm_ray *ray, struct aabox *box, float tmax)
  76 {
  77         float invdir, t0, t1, tmp;
  78         float tmin = 0.0f;
  79
  80         SLABCHECK(x);
  81         SLABCHECK(y);
  82         SLABCHECK(z);
  83
  84         return 1;
  85 }
  86
  87 int ray_bvhnode(cgm_ray *ray, struct bvhnode *bn, float tmax, struct rayhit *hit)
  88 {
  89         int i, res = 0;
  90         struct rayhit hit0;
  91
  92         if(!ray_aabox_any(ray, &bn->aabb, tmax)) {
  93                 return 0;
  94         }
  95
  96         if(!hit) {
  97                 for(i=0; i<bn->num_faces; i++) {
  98                         if(ray_triangle(ray, bn->faces + i, tmax, 0)) {
  99                                 return 1;
 100                         }
 101                 }
 102                 return 0;
 103         }
 104
 105         hit0.t = FLT_MAX;
 106         for(i=0; i<bn->num_faces; i++) {
 107                 if(ray_triangle(ray, bn->faces + i, tmax, hit) && hit->t < hit0.t) {
 108                         hit0 = *hit;
 109                         res = 1;
 110                 }
 111         }
 112         *hit = hit0;
 113         return res;
 114 }