godot/core/math/dynamic_bvh.cpp

437 lines
12 KiB
C++

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