bool BVHAccel::IntersectP(const Ray &ray) const {
if (!nodes) return false;
PBRT_BVH_INTERSECTIONP_STARTED(const_cast<BVHAccel *>(this), const_cast<Ray *>(&ray));
Vector invDir(1.f / ray.d.x, 1.f / ray.d.y, 1.f / ray.d.z);
uint32_t dirIsNeg[3] = { invDir.x < 0, invDir.y < 0, invDir.z < 0 };
uint32_t todo[64];
uint32_t todoOffset = 0, nodeNum = 0;
while (true) {
const LinearBVHNode *node = &nodes[nodeNum];
if (::IntersectP(node->bounds, ray, invDir, dirIsNeg)) {
// Process BVH node _node_ for traversal
if (node->nPrimitives > 0) {
PBRT_BVH_INTERSECTIONP_TRAVERSED_LEAF_NODE(const_cast<LinearBVHNode *>(node));
for (uint32_t i = 0; i < node->nPrimitives; ++i) {
PBRT_BVH_INTERSECTIONP_PRIMITIVE_TEST(const_cast<Primitive *>(primitives[node->primitivesOffset + i].GetPtr()));
if (primitives[node->primitivesOffset+i]->IntersectP(ray)) {
PBRT_BVH_INTERSECTIONP_PRIMITIVE_HIT(const_cast<Primitive *>(primitives[node->primitivesOffset+i].GetPtr()));
// printf("\t BVH Intersect P: thit=%f\n", ray.maxt);
return true;
}
else {
PBRT_BVH_INTERSECTIONP_PRIMITIVE_MISSED(const_cast<Primitive *>(primitives[node->primitivesOffset + i].GetPtr()));
}
}
if (todoOffset == 0) break;
nodeNum = todo[--todoOffset];
}
else {
PBRT_BVH_INTERSECTIONP_TRAVERSED_INTERIOR_NODE(const_cast<LinearBVHNode *>(node));
if (dirIsNeg[node->axis]) {
/// second child first
todo[todoOffset++] = nodeNum + 1;
nodeNum = node->secondChildOffset;
}
else {
todo[todoOffset++] = node->secondChildOffset;
nodeNum = nodeNum + 1;
}
}
}
else {
if (todoOffset == 0) break;
nodeNum = todo[--todoOffset];
}
}
PBRT_BVH_INTERSECTIONP_FINISHED();
return false;
}
bool EBVHAccel::IntersectP(const Ray &ray) const {
if (!nodes) return false;
PBRT_BVH_INTERSECTIONP_STARTED(const_cast<EBVHAccel *>(this), const_cast<Ray *>(&ray));
Vector invDir(1.f / ray.d.x, 1.f / ray.d.y, 1.f / ray.d.z);
uint32_t dirIsNeg[3] = { invDir.x < 0, invDir.y < 0, invDir.z < 0 };
uint32_t todo[64];
uint32_t todoOffset = 0, nodeNum = 0;
std::stack<BBox> stackOfBoxes;
stackOfBoxes.push(this->sceneBoundingBox);
while (true) {
const LinearEBVHNode *node = &nodes[nodeNum];
BBox myBBox = uncompressBBox(BBox(Point(node->bounds_x0, node->bounds_y0, node->bounds_z0), Point(node->bounds_x1, node->bounds_y1, node->bounds_z1)), stackOfBoxes.top());
if (::IntersectP(myBBox, ray, invDir, dirIsNeg)) {
// Process EBVH node _node_ for traversal
if (node->nPrimitives > 0) {
PBRT_BVH_INTERSECTIONP_TRAVERSED_LEAF_NODE(const_cast<LinearEBVHNode *>(node));
for (uint32_t i = 0; i < node->nPrimitives; ++i) {
PBRT_BVH_INTERSECTIONP_PRIMITIVE_TEST(const_cast<Primitive *>(primitives[node->primitivesOffset + i].GetPtr()));
if (primitives[node->primitivesOffset+i]->IntersectP(ray)) {
PBRT_BVH_INTERSECTIONP_PRIMITIVE_HIT(const_cast<Primitive *>(primitives[node->primitivesOffset+i].GetPtr()));
return true;
}
else {
PBRT_BVH_INTERSECTIONP_PRIMITIVE_MISSED(const_cast<Primitive *>(primitives[node->primitivesOffset + i].GetPtr()));
}
}
if (todoOffset == 0) break;
todoOffset--;
nodeNum = todo[todoOffset];
stackOfBoxes.pop();
}
else {
PBRT_BVH_INTERSECTIONP_TRAVERSED_INTERIOR_NODE(const_cast<LinearEBVHNode *>(node));
if (dirIsNeg[node->axis]) {
/// second child first
todo[todoOffset] = nodeNum + 1;
nodeNum = node->secondChildOffset;
todoOffset++;
stackOfBoxes.pop();
stackOfBoxes.push(myBBox);
stackOfBoxes.push(myBBox);
}
else {
todo[todoOffset] = node->secondChildOffset;
nodeNum = nodeNum + 1;
todoOffset++;
stackOfBoxes.pop();
stackOfBoxes.push(myBBox);
stackOfBoxes.push(myBBox);
}
}
}
else {
if (todoOffset == 0) break;
todoOffset--;
nodeNum = todo[todoOffset];
stackOfBoxes.pop();
}
}
PBRT_BVH_INTERSECTIONP_FINISHED();
return false;
}