BVHAccel::BVHAccel(const std::vector<Primitive *> &_primitives,
size_t max_leaf_size)
{
this->primitives = _primitives;
// edge case
if (primitives.empty()) {
return;
}
// calculate root AABB size
BBox bb;
for (size_t i = 0; i < primitives.size(); ++i) {
bb.expand(primitives[i]->get_bbox());
}
root = new BVHNode(bb, 0, primitives.size());
// calculate morton code for each primitives
for (size_t i = 0; i < primitives.size(); ++i) {
unsigned int morton_code = morton3D(bb.getUnitcubePosOf(primitives[i]->get_bbox().centroid()));
primitives[i]->morton_code = morton_code;
}
// sort primitives using morton code
std::sort(primitives.begin(), primitives.end(), mortonCompare);
//construct BVH based on the mortan code
constructBVH(root);
}
BVHAccel::BVHAccel(const std::vector<Primitive *> &_primitives,
size_t max_leaf_size)
{
this->primitives = _primitives;
// edge case
if (primitives.empty()) {
return;
}
// calculate root AABB size
BBox bb;
for (size_t i = 0; i < primitives.size(); ++i) {
bb.expand(primitives[i]->get_bbox());
}
root = new BVHNode(bb, 0, primitives.size());
// calculate morton code for each primitives
for (size_t i = 0; i < primitives.size(); ++i) {
unsigned int morton_code = morton3D(bb.getUnitcubePosOf(primitives[i]->get_bbox().centroid()));
primitives[i]->morton_code = morton_code;
}
// sort primitives using morton code
std::sort(primitives.begin(), primitives.end(), mortonCompare);
// extract bboxes array
std::vector<BBox> bboxes(primitives.size());
for(int i=0; i<primitives.size(); i++) bboxes[i] = primitives[i]->get_bbox();
// extract sorted morton code for parallel binary radix tree construction
unsigned int sorted_morton_codes[primitives.size()];
for (size_t i = 0; i < primitives.size(); ++i) {
sorted_morton_codes[i] = primitives[i]->morton_code;
}
// delegate the binary radix tree construction process to GPU
cout << "start building parallel brtree" << endl;
ParallelBRTreeBuilder builder(sorted_morton_codes, &bboxes[0], primitives.size());
builder.build();
cout << "done." << endl;
leaf_nodes = builder.get_leaf_nodes();
internal_nodes = builder.get_internal_nodes();
builder.freeDeviceMemory();
// construct BVH based on Binary Radix Tree
constructBVHFromBRTree();
// free the host memory because I am a good programmer
builder.freeHostMemory();
}