void flattenTree(TreeNode *root, TreeNode *(&tail)) {
if (root == NULL) {
return;
}
TreeNode *tmp_left = root->left;
TreeNode *tmp_right = root->right;
tail->right = root;
tail->left = NULL;
tail = tail->right;
flattenTree(tmp_left, tail);
flattenTree(tmp_right, tail);
}
int BVH::flattenTree(BVHBuildNode *buildNode, int *offset)
{
BVHLinearNode *node = &m_root[*offset];
node->m_bbox = buildNode->m_bbox;
int tmpOffset = (*offset)++;
if(buildNode->m_numTris > 0){
node->m_firstTriOffset = buildNode->m_firstTriOffset;
node->m_numTris = buildNode->m_numTris;
node->m_axis = buildNode->m_type;
}
else{
node->m_axis = buildNode->m_splitAxis;
node->m_numTris = 0;
flattenTree(buildNode->m_children[0],offset);
node->m_secondChildOffset = flattenTree(buildNode->m_children[1],offset);
}
return tmpOffset;
}
void BVH::build(std::vector<Triangle *> triangles, std::vector<Instance *> *instances)
{
std::cout << "Building BVH" << std::endl;
m_buildData.reserve(triangles.size());
m_triangles = triangles;
for(int i=0;i<triangles.size();i++){
m_buildData.push_back(BVHTriangleInfo(i,AABoundingBox(triangles[i]), 0, 1 ));
}
if(instances != 0){
m_instances = *instances;
for(int i=0;i<instances->size();i++){
m_buildData.push_back(BVHTriangleInfo(i,(*instances)[i]->m_bounds, 1, (*instances)[i]->getNumTris()));
}
}
int numTotalNodes = 0;
BVHBuildNode *buildRoot = recursiveBuild(0,m_buildData.size(),&numTotalNodes);
m_root = new BVHLinearNode[numTotalNodes];
int offset = 0;
flattenTree(buildRoot,&offset);
recursiveDelete(buildRoot);
m_buildData.clear();
writeObjFile("/tmp/bvh.obj");
}
void flatten(TreeNode *root) {
TreeNode dummy(-1);
TreeNode *tail = &dummy;
flattenTree(root, tail);
root = dummy.right;
}