437 lines
12 KiB
C++
437 lines
12 KiB
C++
/*************************************************************************/
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/* dynamic_bvh.cpp */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#include "dynamic_bvh.h"
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void DynamicBVH::_delete_node(Node *p_node) {
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node_allocator.free(p_node);
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}
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void DynamicBVH::_recurse_delete_node(Node *p_node) {
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if (!p_node->is_leaf()) {
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_recurse_delete_node(p_node->childs[0]);
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_recurse_delete_node(p_node->childs[1]);
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}
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if (p_node == bvh_root) {
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bvh_root = nullptr;
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}
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_delete_node(p_node);
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}
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DynamicBVH::Node *DynamicBVH::_create_node(Node *p_parent, void *p_data) {
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Node *node = node_allocator.alloc();
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node->parent = p_parent;
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node->data = p_data;
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return (node);
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}
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DynamicBVH::Node *DynamicBVH::_create_node_with_volume(Node *p_parent, const Volume &p_volume, void *p_data) {
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Node *node = _create_node(p_parent, p_data);
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node->volume = p_volume;
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return node;
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}
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void DynamicBVH::_insert_leaf(Node *p_root, Node *p_leaf) {
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if (!bvh_root) {
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bvh_root = p_leaf;
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p_leaf->parent = nullptr;
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} else {
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if (!p_root->is_leaf()) {
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do {
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p_root = p_root->childs[p_leaf->volume.select_by_proximity(
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p_root->childs[0]->volume,
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p_root->childs[1]->volume)];
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} while (!p_root->is_leaf());
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}
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Node *prev = p_root->parent;
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Node *node = _create_node_with_volume(prev, p_leaf->volume.merge(p_root->volume), nullptr);
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if (prev) {
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prev->childs[p_root->get_index_in_parent()] = node;
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node->childs[0] = p_root;
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p_root->parent = node;
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node->childs[1] = p_leaf;
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p_leaf->parent = node;
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do {
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if (!prev->volume.contains(node->volume)) {
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prev->volume = prev->childs[0]->volume.merge(prev->childs[1]->volume);
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} else {
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break;
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}
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node = prev;
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} while (nullptr != (prev = node->parent));
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} else {
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node->childs[0] = p_root;
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p_root->parent = node;
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node->childs[1] = p_leaf;
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p_leaf->parent = node;
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bvh_root = node;
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}
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}
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}
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DynamicBVH::Node *DynamicBVH::_remove_leaf(Node *leaf) {
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if (leaf == bvh_root) {
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bvh_root = nullptr;
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return (nullptr);
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} else {
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Node *parent = leaf->parent;
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Node *prev = parent->parent;
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Node *sibling = parent->childs[1 - leaf->get_index_in_parent()];
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if (prev) {
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prev->childs[parent->get_index_in_parent()] = sibling;
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sibling->parent = prev;
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_delete_node(parent);
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while (prev) {
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const Volume pb = prev->volume;
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prev->volume = prev->childs[0]->volume.merge(prev->childs[1]->volume);
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if (pb.is_not_equal_to(prev->volume)) {
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prev = prev->parent;
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} else {
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break;
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}
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}
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return (prev ? prev : bvh_root);
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} else {
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bvh_root = sibling;
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sibling->parent = nullptr;
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_delete_node(parent);
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return (bvh_root);
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}
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}
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}
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void DynamicBVH::_fetch_leaves(Node *p_root, LocalVector<Node *> &r_leaves, int p_depth) {
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if (p_root->is_internal() && p_depth) {
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_fetch_leaves(p_root->childs[0], r_leaves, p_depth - 1);
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_fetch_leaves(p_root->childs[1], r_leaves, p_depth - 1);
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_delete_node(p_root);
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} else {
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r_leaves.push_back(p_root);
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}
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}
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// Partitions leaves such that leaves[0, n) are on the
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// left of axis, and leaves[n, count) are on the right
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// of axis. returns N.
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int DynamicBVH::_split(Node **leaves, int p_count, const Vector3 &p_org, const Vector3 &p_axis) {
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int begin = 0;
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int end = p_count;
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for (;;) {
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while (begin != end && leaves[begin]->is_left_of_axis(p_org, p_axis)) {
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++begin;
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}
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if (begin == end) {
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break;
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}
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while (begin != end && !leaves[end - 1]->is_left_of_axis(p_org, p_axis)) {
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--end;
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}
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if (begin == end) {
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break;
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}
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// swap out of place nodes
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--end;
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Node *temp = leaves[begin];
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leaves[begin] = leaves[end];
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leaves[end] = temp;
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++begin;
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}
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return begin;
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}
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DynamicBVH::Volume DynamicBVH::_bounds(Node **leaves, int p_count) {
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Volume volume = leaves[0]->volume;
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for (int i = 1, ni = p_count; i < ni; ++i) {
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volume = volume.merge(leaves[i]->volume);
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}
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return (volume);
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}
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void DynamicBVH::_bottom_up(Node **leaves, int p_count) {
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while (p_count > 1) {
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real_t minsize = Math_INF;
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int minidx[2] = { -1, -1 };
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for (int i = 0; i < p_count; ++i) {
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for (int j = i + 1; j < p_count; ++j) {
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const real_t sz = leaves[i]->volume.merge(leaves[j]->volume).get_size();
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if (sz < minsize) {
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minsize = sz;
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minidx[0] = i;
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minidx[1] = j;
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}
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}
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}
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Node *n[] = { leaves[minidx[0]], leaves[minidx[1]] };
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Node *p = _create_node_with_volume(nullptr, n[0]->volume.merge(n[1]->volume), nullptr);
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p->childs[0] = n[0];
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p->childs[1] = n[1];
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n[0]->parent = p;
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n[1]->parent = p;
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leaves[minidx[0]] = p;
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leaves[minidx[1]] = leaves[p_count - 1];
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--p_count;
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}
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}
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DynamicBVH::Node *DynamicBVH::_top_down(Node **leaves, int p_count, int p_bu_threshold) {
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static const Vector3 axis[] = { Vector3(1, 0, 0), Vector3(0, 1, 0), Vector3(0, 0, 1) };
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ERR_FAIL_COND_V(p_bu_threshold <= 1, nullptr);
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if (p_count > 1) {
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if (p_count > p_bu_threshold) {
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const Volume vol = _bounds(leaves, p_count);
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const Vector3 org = vol.get_center();
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int partition;
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int bestaxis = -1;
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int bestmidp = p_count;
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int splitcount[3][2] = { { 0, 0 }, { 0, 0 }, { 0, 0 } };
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int i;
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for (i = 0; i < p_count; ++i) {
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const Vector3 x = leaves[i]->volume.get_center() - org;
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for (int j = 0; j < 3; ++j) {
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++splitcount[j][x.dot(axis[j]) > 0 ? 1 : 0];
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}
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}
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for (i = 0; i < 3; ++i) {
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if ((splitcount[i][0] > 0) && (splitcount[i][1] > 0)) {
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const int midp = (int)Math::abs(real_t(splitcount[i][0] - splitcount[i][1]));
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if (midp < bestmidp) {
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bestaxis = i;
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bestmidp = midp;
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}
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}
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}
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if (bestaxis >= 0) {
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partition = _split(leaves, p_count, org, axis[bestaxis]);
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ERR_FAIL_COND_V(partition == 0 || partition == p_count, nullptr);
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} else {
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partition = p_count / 2 + 1;
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}
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Node *node = _create_node_with_volume(nullptr, vol, nullptr);
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node->childs[0] = _top_down(&leaves[0], partition, p_bu_threshold);
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node->childs[1] = _top_down(&leaves[partition], p_count - partition, p_bu_threshold);
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node->childs[0]->parent = node;
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node->childs[1]->parent = node;
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return (node);
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} else {
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_bottom_up(leaves, p_count);
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return (leaves[0]);
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}
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}
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return (leaves[0]);
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}
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DynamicBVH::Node *DynamicBVH::_node_sort(Node *n, Node *&r) {
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Node *p = n->parent;
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ERR_FAIL_COND_V(!n->is_internal(), nullptr);
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if (p > n) {
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const int i = n->get_index_in_parent();
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const int j = 1 - i;
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Node *s = p->childs[j];
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Node *q = p->parent;
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ERR_FAIL_COND_V(n != p->childs[i], nullptr);
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if (q) {
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q->childs[p->get_index_in_parent()] = n;
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} else {
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r = n;
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}
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s->parent = n;
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p->parent = n;
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n->parent = q;
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p->childs[0] = n->childs[0];
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p->childs[1] = n->childs[1];
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n->childs[0]->parent = p;
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n->childs[1]->parent = p;
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n->childs[i] = p;
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n->childs[j] = s;
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SWAP(p->volume, n->volume);
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return (p);
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}
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return (n);
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}
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void DynamicBVH::clear() {
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if (bvh_root) {
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_recurse_delete_node(bvh_root);
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}
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lkhd = -1;
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opath = 0;
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}
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void DynamicBVH::optimize_bottom_up() {
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if (bvh_root) {
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LocalVector<Node *> leaves;
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_fetch_leaves(bvh_root, leaves);
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_bottom_up(&leaves[0], leaves.size());
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bvh_root = leaves[0];
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}
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}
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void DynamicBVH::optimize_top_down(int bu_threshold) {
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if (bvh_root) {
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LocalVector<Node *> leaves;
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_fetch_leaves(bvh_root, leaves);
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bvh_root = _top_down(&leaves[0], leaves.size(), bu_threshold);
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}
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}
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void DynamicBVH::optimize_incremental(int passes) {
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if (passes < 0) {
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passes = total_leaves;
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}
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if (bvh_root && (passes > 0)) {
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do {
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Node *node = bvh_root;
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unsigned bit = 0;
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while (node->is_internal()) {
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node = _node_sort(node, bvh_root)->childs[(opath >> bit) & 1];
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bit = (bit + 1) & (sizeof(unsigned) * 8 - 1);
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}
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_update(node);
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++opath;
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} while (--passes);
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}
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}
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DynamicBVH::ID DynamicBVH::insert(const AABB &p_box, void *p_userdata) {
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Volume volume;
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volume.min = p_box.position;
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volume.max = p_box.position + p_box.size;
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Node *leaf = _create_node_with_volume(nullptr, volume, p_userdata);
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_insert_leaf(bvh_root, leaf);
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++total_leaves;
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ID id;
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id.node = leaf;
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return id;
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}
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void DynamicBVH::_update(Node *leaf, int lookahead) {
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Node *root = _remove_leaf(leaf);
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if (root) {
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if (lookahead >= 0) {
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for (int i = 0; (i < lookahead) && root->parent; ++i) {
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root = root->parent;
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}
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} else {
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root = bvh_root;
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}
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}
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_insert_leaf(root, leaf);
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}
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bool DynamicBVH::update(const ID &p_id, const AABB &p_box) {
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ERR_FAIL_COND_V(!p_id.is_valid(), false);
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Node *leaf = p_id.node;
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Volume volume;
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volume.min = p_box.position;
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volume.max = p_box.position + p_box.size;
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if (leaf->volume.min.is_equal_approx(volume.min) && leaf->volume.max.is_equal_approx(volume.max)) {
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// noop
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return false;
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}
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Node *base = _remove_leaf(leaf);
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if (base) {
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if (lkhd >= 0) {
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for (int i = 0; (i < lkhd) && base->parent; ++i) {
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base = base->parent;
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}
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} else {
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base = bvh_root;
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}
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}
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leaf->volume = volume;
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_insert_leaf(base, leaf);
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return true;
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}
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void DynamicBVH::remove(const ID &p_id) {
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ERR_FAIL_COND(!p_id.is_valid());
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Node *leaf = p_id.node;
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_remove_leaf(leaf);
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_delete_node(leaf);
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--total_leaves;
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}
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void DynamicBVH::_extract_leaves(Node *p_node, List<ID> *r_elements) {
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if (p_node->is_internal()) {
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_extract_leaves(p_node->childs[0], r_elements);
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_extract_leaves(p_node->childs[1], r_elements);
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} else {
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ID id;
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id.node = p_node;
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r_elements->push_back(id);
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}
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}
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void DynamicBVH::set_index(uint32_t p_index) {
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ERR_FAIL_COND(bvh_root != nullptr);
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index = p_index;
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}
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uint32_t DynamicBVH::get_index() const {
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return index;
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}
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void DynamicBVH::get_elements(List<ID> *r_elements) {
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if (bvh_root) {
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_extract_leaves(bvh_root, r_elements);
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}
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}
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int DynamicBVH::get_leaf_count() const {
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return total_leaves;
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}
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int DynamicBVH::get_max_depth() const {
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if (bvh_root) {
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int depth = 1;
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int max_depth = 0;
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bvh_root->get_max_depth(depth, max_depth);
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return max_depth;
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} else {
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return 0;
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}
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}
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DynamicBVH::~DynamicBVH() {
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clear();
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}
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