int TriangleMesh::_create_bvh(BVH *p_bvh, BVH **p_bb, int p_from, int p_size, int p_depth, int &max_depth, int &max_alloc) {
if (p_depth > max_depth) {
max_depth = p_depth;
}
if (p_size == 1) {
return p_bb[p_from] - p_bvh;
} else if (p_size == 0) {
return -1;
}
Rect3 aabb;
aabb = p_bb[p_from]->aabb;
for (int i = 1; i < p_size; i++) {
aabb.merge_with(p_bb[p_from + i]->aabb);
}
int li = aabb.get_longest_axis_index();
switch (li) {
case Vector3::AXIS_X: {
SortArray<BVH *, BVHCmpX> sort_x;
sort_x.nth_element(0, p_size, p_size / 2, &p_bb[p_from]);
//sort_x.sort(&p_bb[p_from],p_size);
} break;
case Vector3::AXIS_Y: {
SortArray<BVH *, BVHCmpY> sort_y;
sort_y.nth_element(0, p_size, p_size / 2, &p_bb[p_from]);
//sort_y.sort(&p_bb[p_from],p_size);
} break;
case Vector3::AXIS_Z: {
SortArray<BVH *, BVHCmpZ> sort_z;
sort_z.nth_element(0, p_size, p_size / 2, &p_bb[p_from]);
//sort_z.sort(&p_bb[p_from],p_size);
} break;
}
int left = _create_bvh(p_bvh, p_bb, p_from, p_size / 2, p_depth + 1, max_depth, max_alloc);
int right = _create_bvh(p_bvh, p_bb, p_from + p_size / 2, p_size - p_size / 2, p_depth + 1, max_depth, max_alloc);
int index = max_alloc++;
BVH *_new = &p_bvh[index];
_new->aabb = aabb;
_new->center = aabb.position + aabb.size * 0.5;
_new->face_index = -1;
_new->left = left;
_new->right = right;
return index;
}
_VolumeSW_BVH *_volume_sw_build_bvh(_VolumeSW_BVH_Element *p_elements, int p_size, int &count) {
_VolumeSW_BVH *bvh = memnew(_VolumeSW_BVH);
if (p_size == 1) {
//leaf
bvh->aabb = p_elements[0].aabb;
bvh->left = NULL;
bvh->right = NULL;
bvh->face_index = p_elements->face_index;
count++;
return bvh;
} else {
bvh->face_index = -1;
}
Rect3 aabb;
for (int i = 0; i < p_size; i++) {
if (i == 0)
aabb = p_elements[i].aabb;
else
aabb.merge_with(p_elements[i].aabb);
}
bvh->aabb = aabb;
switch (aabb.get_longest_axis_index()) {
case 0: {
SortArray<_VolumeSW_BVH_Element, _VolumeSW_BVH_CompareX> sort_x;
sort_x.sort(p_elements, p_size);
} break;
case 1: {
SortArray<_VolumeSW_BVH_Element, _VolumeSW_BVH_CompareY> sort_y;
sort_y.sort(p_elements, p_size);
} break;
case 2: {
SortArray<_VolumeSW_BVH_Element, _VolumeSW_BVH_CompareZ> sort_z;
sort_z.sort(p_elements, p_size);
} break;
}
int split = p_size / 2;
bvh->left = _volume_sw_build_bvh(p_elements, split, count);
bvh->right = _volume_sw_build_bvh(&p_elements[split], p_size - split, count);
//printf("branch at %p - %i: %i\n",bvh,count,bvh->face_index);
count++;
return bvh;
}