153 lines
6.0 KiB
C++
153 lines
6.0 KiB
C++
/*
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* KdTree.cpp
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* RVO2-3D Library
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*
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* Copyright 2008 University of North Carolina at Chapel Hill
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Please send all bug reports to <geom@cs.unc.edu>.
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*
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* The authors may be contacted via:
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*
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* Jur van den Berg, Stephen J. Guy, Jamie Snape, Ming C. Lin, Dinesh Manocha
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* Dept. of Computer Science
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* 201 S. Columbia St.
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* Frederick P. Brooks, Jr. Computer Science Bldg.
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* Chapel Hill, N.C. 27599-3175
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* United States of America
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*
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* <http://gamma.cs.unc.edu/RVO2/>
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*/
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#include "KdTree.h"
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#include <algorithm>
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#include "Agent.h"
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#include "Definitions.h"
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namespace RVO {
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const size_t RVO_MAX_LEAF_SIZE = 10;
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KdTree::KdTree() {}
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void KdTree::buildAgentTree(std::vector<Agent *> agents) {
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agents_.swap(agents);
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if (!agents_.empty()) {
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agentTree_.resize(2 * agents_.size() - 1);
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buildAgentTreeRecursive(0, agents_.size(), 0);
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}
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}
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void KdTree::buildAgentTreeRecursive(size_t begin, size_t end, size_t node) {
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agentTree_[node].begin = begin;
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agentTree_[node].end = end;
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agentTree_[node].minCoord = agents_[begin]->position_;
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agentTree_[node].maxCoord = agents_[begin]->position_;
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for (size_t i = begin + 1; i < end; ++i) {
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agentTree_[node].maxCoord[0] = std::max(agentTree_[node].maxCoord[0], agents_[i]->position_.x());
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agentTree_[node].minCoord[0] = std::min(agentTree_[node].minCoord[0], agents_[i]->position_.x());
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agentTree_[node].maxCoord[1] = std::max(agentTree_[node].maxCoord[1], agents_[i]->position_.y());
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agentTree_[node].minCoord[1] = std::min(agentTree_[node].minCoord[1], agents_[i]->position_.y());
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agentTree_[node].maxCoord[2] = std::max(agentTree_[node].maxCoord[2], agents_[i]->position_.z());
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agentTree_[node].minCoord[2] = std::min(agentTree_[node].minCoord[2], agents_[i]->position_.z());
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}
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if (end - begin > RVO_MAX_LEAF_SIZE) {
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/* No leaf node. */
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size_t coord;
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if (agentTree_[node].maxCoord[0] - agentTree_[node].minCoord[0] > agentTree_[node].maxCoord[1] - agentTree_[node].minCoord[1] && agentTree_[node].maxCoord[0] - agentTree_[node].minCoord[0] > agentTree_[node].maxCoord[2] - agentTree_[node].minCoord[2]) {
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coord = 0;
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} else if (agentTree_[node].maxCoord[1] - agentTree_[node].minCoord[1] > agentTree_[node].maxCoord[2] - agentTree_[node].minCoord[2]) {
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coord = 1;
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} else {
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coord = 2;
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}
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const float splitValue = 0.5f * (agentTree_[node].maxCoord[coord] + agentTree_[node].minCoord[coord]);
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size_t left = begin;
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size_t right = end;
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while (left < right) {
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while (left < right && agents_[left]->position_[coord] < splitValue) {
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++left;
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}
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while (right > left && agents_[right - 1]->position_[coord] >= splitValue) {
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--right;
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}
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if (left < right) {
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std::swap(agents_[left], agents_[right - 1]);
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++left;
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--right;
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}
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}
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size_t leftSize = left - begin;
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if (leftSize == 0) {
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++leftSize;
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++left;
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++right;
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}
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agentTree_[node].left = node + 1;
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agentTree_[node].right = node + 2 * leftSize;
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buildAgentTreeRecursive(begin, left, agentTree_[node].left);
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buildAgentTreeRecursive(left, end, agentTree_[node].right);
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}
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}
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void KdTree::computeAgentNeighbors(Agent *agent, float rangeSq) const {
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queryAgentTreeRecursive(agent, rangeSq, 0);
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}
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void KdTree::queryAgentTreeRecursive(Agent *agent, float &rangeSq, size_t node) const {
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if (agentTree_[node].end - agentTree_[node].begin <= RVO_MAX_LEAF_SIZE) {
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for (size_t i = agentTree_[node].begin; i < agentTree_[node].end; ++i) {
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agent->insertAgentNeighbor(agents_[i], rangeSq);
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}
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} else {
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const float distSqLeft = sqr(std::max(0.0f, agentTree_[agentTree_[node].left].minCoord[0] - agent->position_.x())) + sqr(std::max(0.0f, agent->position_.x() - agentTree_[agentTree_[node].left].maxCoord[0])) + sqr(std::max(0.0f, agentTree_[agentTree_[node].left].minCoord[1] - agent->position_.y())) + sqr(std::max(0.0f, agent->position_.y() - agentTree_[agentTree_[node].left].maxCoord[1])) + sqr(std::max(0.0f, agentTree_[agentTree_[node].left].minCoord[2] - agent->position_.z())) + sqr(std::max(0.0f, agent->position_.z() - agentTree_[agentTree_[node].left].maxCoord[2]));
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const float distSqRight = sqr(std::max(0.0f, agentTree_[agentTree_[node].right].minCoord[0] - agent->position_.x())) + sqr(std::max(0.0f, agent->position_.x() - agentTree_[agentTree_[node].right].maxCoord[0])) + sqr(std::max(0.0f, agentTree_[agentTree_[node].right].minCoord[1] - agent->position_.y())) + sqr(std::max(0.0f, agent->position_.y() - agentTree_[agentTree_[node].right].maxCoord[1])) + sqr(std::max(0.0f, agentTree_[agentTree_[node].right].minCoord[2] - agent->position_.z())) + sqr(std::max(0.0f, agent->position_.z() - agentTree_[agentTree_[node].right].maxCoord[2]));
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if (distSqLeft < distSqRight) {
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if (distSqLeft < rangeSq) {
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queryAgentTreeRecursive(agent, rangeSq, agentTree_[node].left);
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if (distSqRight < rangeSq) {
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queryAgentTreeRecursive(agent, rangeSq, agentTree_[node].right);
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}
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}
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} else {
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if (distSqRight < rangeSq) {
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queryAgentTreeRecursive(agent, rangeSq, agentTree_[node].right);
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if (distSqLeft < rangeSq) {
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queryAgentTreeRecursive(agent, rangeSq, agentTree_[node].left);
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}
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}
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}
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}
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}
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} // namespace RVO
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