intersection3f intersect(BVHAccelerator* bvh, int nodeid, const ray3f& ray,
const intersect_func& intersect_elem) {
// grab node
auto& node = bvh->nodes[nodeid];
// intersect bbox
if(not intersect_bbox(ray, node.bbox)) return intersection3f();
// recursively intersect nodes
intersection3f intersection;
// copy the ray to allow for shortening it
auto sray = ray;
if(node.leaf) {
for(int idx = node.start; idx < node.end; idx ++) {
auto i = bvh->prims[idx];
intersection3f sintersection = intersect_elem(i,sray);
if(not sintersection.hit) continue;
if(sintersection.ray_t > intersection.ray_t and intersection.hit) continue;
intersection = sintersection;
sray.tmax = intersection.ray_t;
}
} else {
for(auto n : { node.n0, node.n1 }) {
intersection3f sintersection = intersect(bvh,n,sray,intersect_elem);
if(not sintersection.hit) continue;
if(sintersection.ray_t > intersection.ray_t and intersection.hit) continue;
intersection = sintersection;
sray.tmax = intersection.ray_t;
}
}
return intersection;
}
bool intersect_shadow(BVHAccelerator* bvh, int nodeid, const ray3f& ray,
const intersect_func& intersect_elem_shadow) {
// grab node
auto& node = bvh->nodes[nodeid];
// intersect bbox
if(not intersect_bbox(ray, node.bbox)) return false;
// recursively intersect nodes
if(node.leaf) {
// for(auto idx : range(node.start,node.end)) {
for(int idx = node.start; idx < node.end; idx++) {
auto i = bvh->prims[idx];
if(intersect_elem_shadow(i,ray)) return true;
}
} else {
if(intersect_shadow(bvh,node.n0,ray,intersect_elem_shadow)) return true;
if(intersect_shadow(bvh,node.n1,ray,intersect_elem_shadow)) return true;
}
return false;
}
bool RayTracer::rayIntersectNodeShadow(const Vec3f& orig, const Vec3f& dir, const float maxval, const Node* node) const
{
// Test whether the ray intersects the node's bounding box at all
if (!intersect_bbox(&orig.x, &dir.x, &(node->bbMin).x, &(node->bbMax).x, maxval)) {
return false;
}
// If the node is a leaf node
if (!node->leftChild && !node->rightChild) {
return rayIntersectTriangles(orig, dir, node->startPrim, node->endPrim).triangle ? true : false;
}
if (rayIntersectNodeShadow(orig, dir, maxval, node->leftChild))
return true;
if (rayIntersectNodeShadow(orig, dir, maxval, node->rightChild))
return true;
return false;
}
Hit RayTracer::rayIntersectNode(const Vec3f& orig, const Vec3f& dir, const float maxval, const Node* node) const
{
// Test whether the ray intersects the node's bounding box at all
if (!intersect_bbox(&orig.x, &dir.x, &(node->bbMin).x, &(node->bbMax).x, maxval)) {
return Hit(NULL);
}
// If the node is a leaf node
if (!node->leftChild && !node->rightChild) {
return rayIntersectTriangles(orig, dir, node->startPrim, node->endPrim);
}
Hit left = rayIntersectNode(orig, dir, maxval, node->leftChild);
Hit right = rayIntersectNode(orig, dir, maxval, node->rightChild);
if (!left.triangle && !right.triangle)
return Hit(NULL);
else if (left.tmin < right.tmin)
return left;
else
return right;
}
// intersect bounding box without returning bounds
inline bool intersect_bbox(const ray3f& ray, const range3f& bbox) {
float t0, t1; return intersect_bbox(ray,bbox,t0,t1);
}