// Optimized routine for tracing a shadow ray.
//
// This routine doesn't return the nearest intersection, but simply
// checks if there is any intersection.
int
shadow_check(vec3 ray_origin, vec3 ray_direction)
{
intersection_point ip;
num_rays_shot++;
num_shadow_rays_shot++;
for (int s = 0; s < scene_num_spheres; s++)
{
if (ray_intersects_sphere(&ip, scene_spheres[s], ray_origin, ray_direction))
return 1;
}
if (use_bvh)
{
// Use the BVH for speedy intersection testing
if (find_first_intersected_bvh_triangle(&ip, ray_origin, ray_direction))
return 1;
}
else
{
// Simply iterate over all the triangles in the scene and check for intersection
for (int t = 0; t < scene_num_triangles; t++)
{
if (ray_intersects_triangle(&ip, scene_triangles[t], ray_origin, ray_direction))
return 1;
}
}
return 0;
}
void rayIntersectionNonLightTest(ray_t ray, intersect_t *intersect) {
intersect->t = -1;
// Sphere intersections
for (int m = 0; m < numSpheres; m++) {
ray_intersects_sphere(ray, &spheres[m], intersect);
}
// Triangle intersections
for (int m = 0; m < numTriangles; m++) {
ray_intersects_triangle(ray, &triangles[m], intersect);
}
}
// Returns the nearest hit of the given ray with objects in the scene
// (either a sphere or a triangle).
//
// Returns 1 and sets the intersection point values if there
// is an intersection, returns 0 otherwise.
int
find_first_intersection(intersection_point *ip, vec3 ray_origin, vec3 ray_direction)
{
int have_hit;
float t_nearest;
intersection_point ip2;
num_rays_shot++;
// We have found no hit yet
t_nearest = C_INFINITY;
have_hit = 0;
// First check against spheres in the scene
for (int s = 0; s < scene_num_spheres; s++)
{
// We need a second set of p and n variables, as there's the
// possibility that we'll overwrite a closer intersection already
// found
if (ray_intersects_sphere(&ip2, scene_spheres[s], ray_origin, ray_direction))
{
if (ip2.t < t_nearest)
{
*ip = ip2;
t_nearest = ip2.t;
have_hit = 1;
}
}
}
// Then check against triangles in the scene
if (use_bvh)
{
// Use the BVH to speed up intersection testing
if (find_first_intersected_bvh_triangle(&ip2, ray_origin, ray_direction))
{
if (ip2.t < t_nearest)
{
*ip = ip2;
t_nearest = ip2.t;
have_hit = 1;
}
}
}
else
{
// Simply iterate over all the triangles in the scene and check for intersection
for (int t = 0; t < scene_num_triangles; t++)
{
if (ray_intersects_triangle(&ip2, scene_triangles[t], ray_origin, ray_direction))
{
if (ip2.t < t_nearest)
{
*ip = ip2;
t_nearest = ip2.t;
have_hit = 1;
}
}
}
}
return have_hit;
}
