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231 lines
6.4 KiB
C++
231 lines
6.4 KiB
C++
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// for slow incremental optimization, we will periodically remove each
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// item from the tree and reinsert, to give it a chance to find a better position
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void _logic_item_remove_and_reinsert(uint32_t p_ref_id) {
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// get the reference
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ItemRef &ref = _refs[p_ref_id];
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// no need to optimize inactive items
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if (!ref.is_active()) {
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return;
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}
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// special case of debug draw
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if (ref.item_id == BVHCommon::INVALID) {
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return;
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}
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BVH_ASSERT(ref.tnode_id != BVHCommon::INVALID);
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// some overlay elaborate way to find out which tree the node is in!
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BVHHandle temp_handle;
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temp_handle.set_id(p_ref_id);
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uint32_t tree_id = _handle_get_tree_id(temp_handle);
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// remove and reinsert
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BVHABB_CLASS abb;
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node_remove_item(p_ref_id, tree_id, &abb);
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// we must choose where to add to tree
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ref.tnode_id = _logic_choose_item_add_node(_root_node_id[tree_id], abb);
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_node_add_item(ref.tnode_id, p_ref_id, abb);
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refit_upward_and_balance(ref.tnode_id, tree_id);
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}
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// from randy gaul balance function
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BVHABB_CLASS _logic_abb_merge(const BVHABB_CLASS &a, const BVHABB_CLASS &b) {
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BVHABB_CLASS c = a;
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c.merge(b);
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return c;
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}
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//--------------------------------------------------------------------------------------------------
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/**
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* @file q3DynamicAABBTree.h
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* @author Randy Gaul
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* @date 10/10/2014
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* Copyright (c) 2014 Randy Gaul http://www.randygaul.net
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not
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* be misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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//--------------------------------------------------------------------------------------------------
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// This function is based on the 'Balance' function from Randy Gaul's qu3e
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// https://github.com/RandyGaul/qu3e
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// It is MODIFIED from qu3e version.
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// This is the only function used (and _logic_abb_merge helper function).
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int32_t _logic_balance(int32_t iA, uint32_t p_tree_id) {
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//return iA; // uncomment this to bypass balance
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TNode *A = &_nodes[iA];
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if (A->is_leaf() || A->height == 1) {
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return iA;
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}
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/* A
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* / \
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* B C
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* / \ / \
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* D E F G
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*/
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CRASH_COND(A->num_children != 2);
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int32_t iB = A->children[0];
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int32_t iC = A->children[1];
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TNode *B = &_nodes[iB];
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TNode *C = &_nodes[iC];
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int32_t balance = C->height - B->height;
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// C is higher, promote C
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if (balance > 1) {
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int32_t iF = C->children[0];
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int32_t iG = C->children[1];
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TNode *F = &_nodes[iF];
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TNode *G = &_nodes[iG];
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// grandParent point to C
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if (A->parent_id != BVHCommon::INVALID) {
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if (_nodes[A->parent_id].children[0] == iA) {
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_nodes[A->parent_id].children[0] = iC;
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} else {
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_nodes[A->parent_id].children[1] = iC;
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}
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} else {
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// check this .. seems dodgy
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change_root_node(iC, p_tree_id);
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}
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// Swap A and C
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C->children[0] = iA;
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C->parent_id = A->parent_id;
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A->parent_id = iC;
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// Finish rotation
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if (F->height > G->height) {
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C->children[1] = iF;
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A->children[1] = iG;
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G->parent_id = iA;
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A->aabb = _logic_abb_merge(B->aabb, G->aabb);
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C->aabb = _logic_abb_merge(A->aabb, F->aabb);
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A->height = 1 + MAX(B->height, G->height);
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C->height = 1 + MAX(A->height, F->height);
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}
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else {
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C->children[1] = iG;
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A->children[1] = iF;
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F->parent_id = iA;
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A->aabb = _logic_abb_merge(B->aabb, F->aabb);
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C->aabb = _logic_abb_merge(A->aabb, G->aabb);
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A->height = 1 + MAX(B->height, F->height);
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C->height = 1 + MAX(A->height, G->height);
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}
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return iC;
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}
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// B is higher, promote B
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else if (balance < -1) {
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int32_t iD = B->children[0];
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int32_t iE = B->children[1];
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TNode *D = &_nodes[iD];
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TNode *E = &_nodes[iE];
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// grandParent point to B
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if (A->parent_id != BVHCommon::INVALID) {
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if (_nodes[A->parent_id].children[0] == iA) {
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_nodes[A->parent_id].children[0] = iB;
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} else {
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_nodes[A->parent_id].children[1] = iB;
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}
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}
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else {
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// check this .. seems dodgy
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change_root_node(iB, p_tree_id);
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}
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// Swap A and B
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B->children[1] = iA;
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B->parent_id = A->parent_id;
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A->parent_id = iB;
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// Finish rotation
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if (D->height > E->height) {
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B->children[0] = iD;
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A->children[0] = iE;
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E->parent_id = iA;
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A->aabb = _logic_abb_merge(C->aabb, E->aabb);
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B->aabb = _logic_abb_merge(A->aabb, D->aabb);
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A->height = 1 + MAX(C->height, E->height);
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B->height = 1 + MAX(A->height, D->height);
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}
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else {
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B->children[0] = iE;
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A->children[0] = iD;
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D->parent_id = iA;
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A->aabb = _logic_abb_merge(C->aabb, D->aabb);
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B->aabb = _logic_abb_merge(A->aabb, E->aabb);
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A->height = 1 + MAX(C->height, D->height);
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B->height = 1 + MAX(A->height, E->height);
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}
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return iB;
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}
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return iA;
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}
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// either choose an existing node to add item to, or create a new node and return this
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uint32_t _logic_choose_item_add_node(uint32_t p_node_id, const BVHABB_CLASS &p_aabb) {
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while (true) {
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BVH_ASSERT(p_node_id != BVHCommon::INVALID);
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TNode &tnode = _nodes[p_node_id];
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if (tnode.is_leaf()) {
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// if a leaf, and non full, use this to add to
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if (!node_is_leaf_full(tnode)) {
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return p_node_id;
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}
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// else split the leaf, and use one of the children to add to
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return split_leaf(p_node_id, p_aabb);
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}
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// this should not happen???
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// is still happening, need to debug and find circumstances. Is not that serious
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// but would be nice to prevent. I think it only happens with the root node.
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if (tnode.num_children == 1) {
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WARN_PRINT_ONCE("BVH::recursive_choose_item_add_node, node with 1 child, recovering");
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p_node_id = tnode.children[0];
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} else {
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BVH_ASSERT(tnode.num_children == 2);
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TNode &childA = _nodes[tnode.children[0]];
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TNode &childB = _nodes[tnode.children[1]];
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int which = p_aabb.select_by_proximity(childA.aabb, childB.aabb);
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p_node_id = tnode.children[which];
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}
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}
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}
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