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

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