working hack. now do it properly with intervals

[csgray] / src / geom.c

diff --git a/src/geom.c b/src/geom.c
index ee7cb7d..1961aed 100644 (file)
--- a/src/geom.c
+++ b/src/geom.c
@@ -4,6 +4,8 @@
 #include "geom.h"
 #include "matrix.h"
 
+#define EPSILON                1e-6f
+
 /* TODO custom hit allocator */
 struct hit *alloc_hit(void)
 {
@@ -15,6 +17,20 @@ struct hit *alloc_hit(void)
        return hit;
 }
 
+struct hit *alloc_hits(int n)
+{
+       int i;
+       struct hit *list = 0;
+
+       for(i=0; i<n; i++) {
+               struct hit *hit = alloc_hit();
+               hit->next = list;
+               list = hit;
+       }
+       return list;
+}
+
+
 void free_hit(struct hit *hit)
 {
        free(hit);
@@ -52,8 +68,9 @@ struct hit *ray_intersect(struct ray *ray, csg_object *o)
 
 struct hit *ray_sphere(struct ray *ray, csg_object *o)
 {
-       float a, b, c, d, sqrt_d, t0, t1, t, sq_rad;
-       struct hit *hit;
+       int i;
+       float a, b, c, d, sqrt_d, t[2], sq_rad, tmp;
+       struct hit *hit, *hitlist;
        struct ray locray = *ray;
 
        if(o->sph.rad == 0.0f) {
@@ -68,27 +85,39 @@ struct hit *ray_sphere(struct ray *ray, csg_object *o)
        c = (locray.x * locray.x + locray.y * locray.y + locray.z * locray.z) - sq_rad;
 
        d = b * b - 4.0f * a * c;
-       if(d < 1e-6) return 0;
+       if(d < EPSILON) return 0;
 
        sqrt_d = sqrt(d);
-       t0 = (-b + sqrt_d) / (2.0f * a);
-       t1 = (-b - sqrt_d) / (2.0f * a);
-
-       if(t0 < 1e-6) t0 = t1;
-       if(t1 < 1e-6) t1 = t0;
-       t = t0 < t1 ? t0 : t1;
-       if(t < 1e-6) return 0;
-
-       hit = alloc_hit();
-       hit->t = t;
-       hit->x = ray->x + ray->dx * t;
-       hit->y = ray->y + ray->dy * t;
-       hit->z = ray->z + ray->dz * t;
-       hit->nx = hit->x / o->sph.rad;
-       hit->ny = hit->y / o->sph.rad;
-       hit->nz = hit->z / o->sph.rad;
-       hit->o = o;
-       return hit;
+       t[0] = (-b + sqrt_d) / (2.0f * a);
+       t[1] = (-b - sqrt_d) / (2.0f * a);
+
+       if(t[0] < EPSILON && t[1] < EPSILON) {
+               return 0;
+       }
+
+       if(t[1] < t[0]) {
+               tmp = t[0];
+               t[0] = t[1];
+               t[1] = tmp;
+       }
+
+       hitlist = hit = alloc_hits(2);
+       for(i=0; i<2; i++) {
+               float c[3] = {0, 0, 0};
+               mat4_xform3(c, o->ob.xform, c);
+
+               hit->t = t[i];
+               hit->x = ray->x + ray->dx * t[i];
+               hit->y = ray->y + ray->dy * t[i];
+               hit->z = ray->z + ray->dz * t[i];
+               hit->nx = (hit->x - c[0]) / o->sph.rad;
+               hit->ny = (hit->y - c[1]) / o->sph.rad;
+               hit->nz = (hit->z - c[2]) / o->sph.rad;
+               hit->o = o;
+
+               hit = hit->next;
+       }
+       return hitlist;
 }
 
 struct hit *ray_cylinder(struct ray *ray, csg_object *o)
@@ -107,18 +136,19 @@ struct hit *ray_plane(struct ray *ray, csg_object *o)
 
        xform_ray(&locray, o->ob.inv_xform);
 
+       ndotr = o->plane.nx * locray.dx + o->plane.ny * locray.dy + o->plane.nz * locray.dz;
+       if(fabs(ndotr) < EPSILON) return 0;
+
        vx = o->plane.nx * o->plane.d - locray.x;
        vy = o->plane.ny * o->plane.d - locray.y;
        vz = o->plane.nz * o->plane.d - locray.z;
 
        ndotv = o->plane.nx * vx + o->plane.ny * vy + o->plane.nz * vz;
-       if(fabs(ndotv) < 1e-6) return 0;
 
-       ndotr = o->plane.nx * locray.dx + o->plane.ny * locray.dy + o->plane.nz * locray.dz;
-       t = ndotr / ndotv;
+       t = ndotv / ndotr;
 
-       if(t > 1e-6) {
-               hit = alloc_hit();
+       if(t > EPSILON) {
+               hit = alloc_hits(1);
                hit->t = t;
                hit->x = ray->x + ray->dx * t;
                hit->y = ray->y + ray->dy * t;
@@ -136,16 +166,16 @@ struct hit *ray_csg_un(struct ray *ray, csg_object *o)
        struct hit *hita, *hitb;
 
        hita = ray_intersect(ray, o->un.a);
-       hitb = ray_intersect(ray, o->un.a);
+       hitb = ray_intersect(ray, o->un.b);
 
        if(!hita) return hitb;
        if(!hitb) return hita;
 
        if(hita->t < hitb->t) {
-               free_hit(hitb);
+               free_hit_list(hitb);
                return hita;
        }
-       free_hit(hita);
+       free_hit_list(hita);
        return hitb;
 }
 
@@ -154,9 +184,50 @@ struct hit *ray_csg_isect(struct ray *ray, csg_object *o)
        return 0;
 }
 
+static struct hit *first(struct hit *hlist)
+{
+       return hlist;
+}
+
+static struct hit *last(struct hit *hlist)
+{
+       while(hlist->next) {
+               hlist = hlist->next;
+       }
+       return hlist;
+}
+
 struct hit *ray_csg_sub(struct ray *ray, csg_object *o)
 {
-       return 0;
+       struct hit *hita, *hitb, *lasthit, tmp;
+
+       hita = ray_intersect(ray, o->sub.a);
+       hitb = ray_intersect(ray, o->sub.b);
+
+       if(!hita) return 0;
+       if(!hitb) return hita;
+
+       if(first(hita)->t < first(hitb)->t) {
+               free_hit_list(hitb);
+               return hita;
+       }
+       if(first(hita)->t < (lasthit = last(hitb))->t) {
+               /* overlapping */
+               tmp = *hitb;
+               *hitb = *lasthit;
+
+               free_hit_list(tmp.next);
+
+               hitb->nx = -hitb->nx;
+               hitb->ny = -hitb->ny;
+               hitb->nz = -hitb->nz;
+
+               free_hit_list(hita);
+               return hitb;
+       }
+
+       free_hit_list(hitb);
+       return hita;
 }