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358 lines
12 KiB
C++
358 lines
12 KiB
C++
/*
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* KdTree2d.cpp
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* RVO2 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 "KdTree2d.h"
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#include "Agent2d.h"
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#include "RVOSimulator2d.h"
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#include "Obstacle2d.h"
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namespace RVO2D {
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KdTree2D::KdTree2D(RVOSimulator2D *sim) : obstacleTree_(NULL), sim_(sim) { }
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KdTree2D::~KdTree2D()
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{
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deleteObstacleTree(obstacleTree_);
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}
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void KdTree2D::buildAgentTree(std::vector<Agent2D *> agents)
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{
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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 KdTree2D::buildAgentTreeRecursive(size_t begin, size_t end, size_t node)
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{
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agentTree_[node].begin = begin;
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agentTree_[node].end = end;
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agentTree_[node].minX = agentTree_[node].maxX = agents_[begin]->position_.x();
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agentTree_[node].minY = agentTree_[node].maxY = agents_[begin]->position_.y();
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for (size_t i = begin + 1; i < end; ++i) {
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agentTree_[node].maxX = std::max(agentTree_[node].maxX, agents_[i]->position_.x());
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agentTree_[node].minX = std::min(agentTree_[node].minX, agents_[i]->position_.x());
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agentTree_[node].maxY = std::max(agentTree_[node].maxY, agents_[i]->position_.y());
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agentTree_[node].minY = std::min(agentTree_[node].minY, agents_[i]->position_.y());
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}
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if (end - begin > MAX_LEAF_SIZE) {
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/* No leaf node. */
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const bool isVertical = (agentTree_[node].maxX - agentTree_[node].minX > agentTree_[node].maxY - agentTree_[node].minY);
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const float splitValue = (isVertical ? 0.5f * (agentTree_[node].maxX + agentTree_[node].minX) : 0.5f * (agentTree_[node].maxY + agentTree_[node].minY));
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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 && (isVertical ? agents_[left]->position_.x() : agents_[left]->position_.y()) < splitValue) {
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++left;
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}
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while (right > left && (isVertical ? agents_[right - 1]->position_.x() : agents_[right - 1]->position_.y()) >= 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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if (left == begin) {
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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 * (left - begin);
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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 KdTree2D::buildObstacleTree(std::vector<Obstacle2D *> obstacles)
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{
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deleteObstacleTree(obstacleTree_);
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obstacleTree_ = buildObstacleTreeRecursive(obstacles);
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}
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KdTree2D::ObstacleTreeNode *KdTree2D::buildObstacleTreeRecursive(const std::vector<Obstacle2D *> &obstacles)
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{
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if (obstacles.empty()) {
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return NULL;
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}
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else {
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ObstacleTreeNode *const node = new ObstacleTreeNode;
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size_t optimalSplit = 0;
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size_t minLeft = obstacles.size();
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size_t minRight = obstacles.size();
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for (size_t i = 0; i < obstacles.size(); ++i) {
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size_t leftSize = 0;
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size_t rightSize = 0;
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const Obstacle2D *const obstacleI1 = obstacles[i];
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const Obstacle2D *const obstacleI2 = obstacleI1->nextObstacle_;
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/* Compute optimal split node. */
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for (size_t j = 0; j < obstacles.size(); ++j) {
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if (i == j) {
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continue;
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}
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const Obstacle2D *const obstacleJ1 = obstacles[j];
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const Obstacle2D *const obstacleJ2 = obstacleJ1->nextObstacle_;
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const float j1LeftOfI = leftOf(obstacleI1->point_, obstacleI2->point_, obstacleJ1->point_);
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const float j2LeftOfI = leftOf(obstacleI1->point_, obstacleI2->point_, obstacleJ2->point_);
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if (j1LeftOfI >= -RVO_EPSILON && j2LeftOfI >= -RVO_EPSILON) {
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++leftSize;
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}
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else if (j1LeftOfI <= RVO_EPSILON && j2LeftOfI <= RVO_EPSILON) {
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++rightSize;
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}
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else {
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++leftSize;
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++rightSize;
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}
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if (std::make_pair(std::max(leftSize, rightSize), std::min(leftSize, rightSize)) >= std::make_pair(std::max(minLeft, minRight), std::min(minLeft, minRight))) {
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break;
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}
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}
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if (std::make_pair(std::max(leftSize, rightSize), std::min(leftSize, rightSize)) < std::make_pair(std::max(minLeft, minRight), std::min(minLeft, minRight))) {
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minLeft = leftSize;
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minRight = rightSize;
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optimalSplit = i;
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}
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}
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/* Build split node. */
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std::vector<Obstacle2D *> leftObstacles(minLeft);
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std::vector<Obstacle2D *> rightObstacles(minRight);
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size_t leftCounter = 0;
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size_t rightCounter = 0;
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const size_t i = optimalSplit;
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const Obstacle2D *const obstacleI1 = obstacles[i];
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const Obstacle2D *const obstacleI2 = obstacleI1->nextObstacle_;
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for (size_t j = 0; j < obstacles.size(); ++j) {
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if (i == j) {
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continue;
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}
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Obstacle2D *const obstacleJ1 = obstacles[j];
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Obstacle2D *const obstacleJ2 = obstacleJ1->nextObstacle_;
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const float j1LeftOfI = leftOf(obstacleI1->point_, obstacleI2->point_, obstacleJ1->point_);
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const float j2LeftOfI = leftOf(obstacleI1->point_, obstacleI2->point_, obstacleJ2->point_);
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if (j1LeftOfI >= -RVO_EPSILON && j2LeftOfI >= -RVO_EPSILON) {
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leftObstacles[leftCounter++] = obstacles[j];
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}
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else if (j1LeftOfI <= RVO_EPSILON && j2LeftOfI <= RVO_EPSILON) {
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rightObstacles[rightCounter++] = obstacles[j];
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}
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else {
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/* Split obstacle j. */
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const float t = det(obstacleI2->point_ - obstacleI1->point_, obstacleJ1->point_ - obstacleI1->point_) / det(obstacleI2->point_ - obstacleI1->point_, obstacleJ1->point_ - obstacleJ2->point_);
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const Vector2 splitpoint = obstacleJ1->point_ + t * (obstacleJ2->point_ - obstacleJ1->point_);
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Obstacle2D *const newObstacle = new Obstacle2D();
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newObstacle->point_ = splitpoint;
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newObstacle->prevObstacle_ = obstacleJ1;
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newObstacle->nextObstacle_ = obstacleJ2;
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newObstacle->isConvex_ = true;
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newObstacle->unitDir_ = obstacleJ1->unitDir_;
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newObstacle->id_ = sim_->obstacles_.size();
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sim_->obstacles_.push_back(newObstacle);
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obstacleJ1->nextObstacle_ = newObstacle;
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obstacleJ2->prevObstacle_ = newObstacle;
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if (j1LeftOfI > 0.0f) {
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leftObstacles[leftCounter++] = obstacleJ1;
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rightObstacles[rightCounter++] = newObstacle;
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}
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else {
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rightObstacles[rightCounter++] = obstacleJ1;
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leftObstacles[leftCounter++] = newObstacle;
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}
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}
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}
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node->obstacle = obstacleI1;
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node->left = buildObstacleTreeRecursive(leftObstacles);
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node->right = buildObstacleTreeRecursive(rightObstacles);
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return node;
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}
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}
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void KdTree2D::computeAgentNeighbors(Agent2D *agent, float &rangeSq) const
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{
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queryAgentTreeRecursive(agent, rangeSq, 0);
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}
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void KdTree2D::computeObstacleNeighbors(Agent2D *agent, float rangeSq) const
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{
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queryObstacleTreeRecursive(agent, rangeSq, obstacleTree_);
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}
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void KdTree2D::deleteObstacleTree(ObstacleTreeNode *node)
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{
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if (node != NULL) {
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deleteObstacleTree(node->left);
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deleteObstacleTree(node->right);
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delete node;
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}
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}
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void KdTree2D::queryAgentTreeRecursive(Agent2D *agent, float &rangeSq, size_t node) const
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{
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if (agentTree_[node].end - agentTree_[node].begin <= 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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}
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else {
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const float distSqLeft = sqr(std::max(0.0f, agentTree_[agentTree_[node].left].minX - agent->position_.x())) + sqr(std::max(0.0f, agent->position_.x() - agentTree_[agentTree_[node].left].maxX)) + sqr(std::max(0.0f, agentTree_[agentTree_[node].left].minY - agent->position_.y())) + sqr(std::max(0.0f, agent->position_.y() - agentTree_[agentTree_[node].left].maxY));
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const float distSqRight = sqr(std::max(0.0f, agentTree_[agentTree_[node].right].minX - agent->position_.x())) + sqr(std::max(0.0f, agent->position_.x() - agentTree_[agentTree_[node].right].maxX)) + sqr(std::max(0.0f, agentTree_[agentTree_[node].right].minY - agent->position_.y())) + sqr(std::max(0.0f, agent->position_.y() - agentTree_[agentTree_[node].right].maxY));
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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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}
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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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void KdTree2D::queryObstacleTreeRecursive(Agent2D *agent, float rangeSq, const ObstacleTreeNode *node) const
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{
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if (node == NULL) {
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return;
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}
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else {
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const Obstacle2D *const obstacle1 = node->obstacle;
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const Obstacle2D *const obstacle2 = obstacle1->nextObstacle_;
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const float agentLeftOfLine = leftOf(obstacle1->point_, obstacle2->point_, agent->position_);
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queryObstacleTreeRecursive(agent, rangeSq, (agentLeftOfLine >= 0.0f ? node->left : node->right));
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const float distSqLine = sqr(agentLeftOfLine) / absSq(obstacle2->point_ - obstacle1->point_);
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if (distSqLine < rangeSq) {
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if (agentLeftOfLine < 0.0f) {
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/*
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* Try obstacle at this node only if agent is on right side of
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* obstacle (and can see obstacle).
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*/
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agent->insertObstacleNeighbor(node->obstacle, rangeSq);
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}
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/* Try other side of line. */
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queryObstacleTreeRecursive(agent, rangeSq, (agentLeftOfLine >= 0.0f ? node->right : node->left));
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}
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}
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}
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bool KdTree2D::queryVisibility(const Vector2 &q1, const Vector2 &q2, float radius) const
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{
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return queryVisibilityRecursive(q1, q2, radius, obstacleTree_);
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}
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bool KdTree2D::queryVisibilityRecursive(const Vector2 &q1, const Vector2 &q2, float radius, const ObstacleTreeNode *node) const
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{
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if (node == NULL) {
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return true;
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}
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else {
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const Obstacle2D *const obstacle1 = node->obstacle;
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const Obstacle2D *const obstacle2 = obstacle1->nextObstacle_;
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const float q1LeftOfI = leftOf(obstacle1->point_, obstacle2->point_, q1);
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const float q2LeftOfI = leftOf(obstacle1->point_, obstacle2->point_, q2);
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const float invLengthI = 1.0f / absSq(obstacle2->point_ - obstacle1->point_);
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if (q1LeftOfI >= 0.0f && q2LeftOfI >= 0.0f) {
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return queryVisibilityRecursive(q1, q2, radius, node->left) && ((sqr(q1LeftOfI) * invLengthI >= sqr(radius) && sqr(q2LeftOfI) * invLengthI >= sqr(radius)) || queryVisibilityRecursive(q1, q2, radius, node->right));
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}
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else if (q1LeftOfI <= 0.0f && q2LeftOfI <= 0.0f) {
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return queryVisibilityRecursive(q1, q2, radius, node->right) && ((sqr(q1LeftOfI) * invLengthI >= sqr(radius) && sqr(q2LeftOfI) * invLengthI >= sqr(radius)) || queryVisibilityRecursive(q1, q2, radius, node->left));
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}
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else if (q1LeftOfI >= 0.0f && q2LeftOfI <= 0.0f) {
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/* One can see through obstacle from left to right. */
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return queryVisibilityRecursive(q1, q2, radius, node->left) && queryVisibilityRecursive(q1, q2, radius, node->right);
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}
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else {
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const float point1LeftOfQ = leftOf(q1, q2, obstacle1->point_);
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const float point2LeftOfQ = leftOf(q1, q2, obstacle2->point_);
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const float invLengthQ = 1.0f / absSq(q2 - q1);
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return (point1LeftOfQ * point2LeftOfQ >= 0.0f && sqr(point1LeftOfQ) * invLengthQ > sqr(radius) && sqr(point2LeftOfQ) * invLengthQ > sqr(radius) && queryVisibilityRecursive(q1, q2, radius, node->left) && queryVisibilityRecursive(q1, q2, radius, node->right));
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}
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}
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}
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}
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