virtualx-engine/thirdparty/rvo2/rvo2_2d/KdTree2d.cpp
2024-02-18 13:31:05 -07:00

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C++

/*
* KdTree2d.cpp
* RVO2 Library
*
* Copyright 2008 University of North Carolina at Chapel Hill
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Please send all bug reports to <geom@cs.unc.edu>.
*
* The authors may be contacted via:
*
* Jur van den Berg, Stephen J. Guy, Jamie Snape, Ming C. Lin, Dinesh Manocha
* Dept. of Computer Science
* 201 S. Columbia St.
* Frederick P. Brooks, Jr. Computer Science Bldg.
* Chapel Hill, N.C. 27599-3175
* United States of America
*
* <http://gamma.cs.unc.edu/RVO2/>
*/
#include "KdTree2d.h"
#include "Agent2d.h"
#include "RVOSimulator2d.h"
#include "Obstacle2d.h"
namespace RVO2D {
KdTree2D::KdTree2D(RVOSimulator2D *sim) : obstacleTree_(NULL), sim_(sim) { }
KdTree2D::~KdTree2D()
{
deleteObstacleTree(obstacleTree_);
}
void KdTree2D::buildAgentTree(std::vector<Agent2D *> agents)
{
agents_.swap(agents);
if (!agents_.empty()) {
agentTree_.resize(2 * agents_.size() - 1);
buildAgentTreeRecursive(0, agents_.size(), 0);
}
}
void KdTree2D::buildAgentTreeRecursive(size_t begin, size_t end, size_t node)
{
agentTree_[node].begin = begin;
agentTree_[node].end = end;
agentTree_[node].minX = agentTree_[node].maxX = agents_[begin]->position_.x();
agentTree_[node].minY = agentTree_[node].maxY = agents_[begin]->position_.y();
for (size_t i = begin + 1; i < end; ++i) {
agentTree_[node].maxX = std::max(agentTree_[node].maxX, agents_[i]->position_.x());
agentTree_[node].minX = std::min(agentTree_[node].minX, agents_[i]->position_.x());
agentTree_[node].maxY = std::max(agentTree_[node].maxY, agents_[i]->position_.y());
agentTree_[node].minY = std::min(agentTree_[node].minY, agents_[i]->position_.y());
}
if (end - begin > MAX_LEAF_SIZE) {
/* No leaf node. */
const bool isVertical = (agentTree_[node].maxX - agentTree_[node].minX > agentTree_[node].maxY - agentTree_[node].minY);
const float splitValue = (isVertical ? 0.5f * (agentTree_[node].maxX + agentTree_[node].minX) : 0.5f * (agentTree_[node].maxY + agentTree_[node].minY));
size_t left = begin;
size_t right = end;
while (left < right) {
while (left < right && (isVertical ? agents_[left]->position_.x() : agents_[left]->position_.y()) < splitValue) {
++left;
}
while (right > left && (isVertical ? agents_[right - 1]->position_.x() : agents_[right - 1]->position_.y()) >= splitValue) {
--right;
}
if (left < right) {
std::swap(agents_[left], agents_[right - 1]);
++left;
--right;
}
}
if (left == begin) {
++left;
++right;
}
agentTree_[node].left = node + 1;
agentTree_[node].right = node + 2 * (left - begin);
buildAgentTreeRecursive(begin, left, agentTree_[node].left);
buildAgentTreeRecursive(left, end, agentTree_[node].right);
}
}
void KdTree2D::buildObstacleTree(std::vector<Obstacle2D *> obstacles)
{
deleteObstacleTree(obstacleTree_);
obstacleTree_ = buildObstacleTreeRecursive(obstacles);
}
KdTree2D::ObstacleTreeNode *KdTree2D::buildObstacleTreeRecursive(const std::vector<Obstacle2D *> &obstacles)
{
if (obstacles.empty()) {
return NULL;
}
else {
ObstacleTreeNode *const node = new ObstacleTreeNode;
size_t optimalSplit = 0;
size_t minLeft = obstacles.size();
size_t minRight = obstacles.size();
for (size_t i = 0; i < obstacles.size(); ++i) {
size_t leftSize = 0;
size_t rightSize = 0;
const Obstacle2D *const obstacleI1 = obstacles[i];
const Obstacle2D *const obstacleI2 = obstacleI1->nextObstacle_;
/* Compute optimal split node. */
for (size_t j = 0; j < obstacles.size(); ++j) {
if (i == j) {
continue;
}
const Obstacle2D *const obstacleJ1 = obstacles[j];
const Obstacle2D *const obstacleJ2 = obstacleJ1->nextObstacle_;
const float j1LeftOfI = leftOf(obstacleI1->point_, obstacleI2->point_, obstacleJ1->point_);
const float j2LeftOfI = leftOf(obstacleI1->point_, obstacleI2->point_, obstacleJ2->point_);
if (j1LeftOfI >= -RVO_EPSILON && j2LeftOfI >= -RVO_EPSILON) {
++leftSize;
}
else if (j1LeftOfI <= RVO_EPSILON && j2LeftOfI <= RVO_EPSILON) {
++rightSize;
}
else {
++leftSize;
++rightSize;
}
if (std::make_pair(std::max(leftSize, rightSize), std::min(leftSize, rightSize)) >= std::make_pair(std::max(minLeft, minRight), std::min(minLeft, minRight))) {
break;
}
}
if (std::make_pair(std::max(leftSize, rightSize), std::min(leftSize, rightSize)) < std::make_pair(std::max(minLeft, minRight), std::min(minLeft, minRight))) {
minLeft = leftSize;
minRight = rightSize;
optimalSplit = i;
}
}
/* Build split node. */
std::vector<Obstacle2D *> leftObstacles(minLeft);
std::vector<Obstacle2D *> rightObstacles(minRight);
size_t leftCounter = 0;
size_t rightCounter = 0;
const size_t i = optimalSplit;
const Obstacle2D *const obstacleI1 = obstacles[i];
const Obstacle2D *const obstacleI2 = obstacleI1->nextObstacle_;
for (size_t j = 0; j < obstacles.size(); ++j) {
if (i == j) {
continue;
}
Obstacle2D *const obstacleJ1 = obstacles[j];
Obstacle2D *const obstacleJ2 = obstacleJ1->nextObstacle_;
const float j1LeftOfI = leftOf(obstacleI1->point_, obstacleI2->point_, obstacleJ1->point_);
const float j2LeftOfI = leftOf(obstacleI1->point_, obstacleI2->point_, obstacleJ2->point_);
if (j1LeftOfI >= -RVO_EPSILON && j2LeftOfI >= -RVO_EPSILON) {
leftObstacles[leftCounter++] = obstacles[j];
}
else if (j1LeftOfI <= RVO_EPSILON && j2LeftOfI <= RVO_EPSILON) {
rightObstacles[rightCounter++] = obstacles[j];
}
else {
/* Split obstacle j. */
const float t = det(obstacleI2->point_ - obstacleI1->point_, obstacleJ1->point_ - obstacleI1->point_) / det(obstacleI2->point_ - obstacleI1->point_, obstacleJ1->point_ - obstacleJ2->point_);
const Vector2 splitpoint = obstacleJ1->point_ + t * (obstacleJ2->point_ - obstacleJ1->point_);
Obstacle2D *const newObstacle = new Obstacle2D();
newObstacle->point_ = splitpoint;
newObstacle->prevObstacle_ = obstacleJ1;
newObstacle->nextObstacle_ = obstacleJ2;
newObstacle->isConvex_ = true;
newObstacle->unitDir_ = obstacleJ1->unitDir_;
newObstacle->id_ = sim_->obstacles_.size();
sim_->obstacles_.push_back(newObstacle);
obstacleJ1->nextObstacle_ = newObstacle;
obstacleJ2->prevObstacle_ = newObstacle;
if (j1LeftOfI > 0.0f) {
leftObstacles[leftCounter++] = obstacleJ1;
rightObstacles[rightCounter++] = newObstacle;
}
else {
rightObstacles[rightCounter++] = obstacleJ1;
leftObstacles[leftCounter++] = newObstacle;
}
}
}
node->obstacle = obstacleI1;
node->left = buildObstacleTreeRecursive(leftObstacles);
node->right = buildObstacleTreeRecursive(rightObstacles);
return node;
}
}
void KdTree2D::computeAgentNeighbors(Agent2D *agent, float &rangeSq) const
{
queryAgentTreeRecursive(agent, rangeSq, 0);
}
void KdTree2D::computeObstacleNeighbors(Agent2D *agent, float rangeSq) const
{
queryObstacleTreeRecursive(agent, rangeSq, obstacleTree_);
}
void KdTree2D::deleteObstacleTree(ObstacleTreeNode *node)
{
if (node != NULL) {
deleteObstacleTree(node->left);
deleteObstacleTree(node->right);
delete node;
}
}
void KdTree2D::queryAgentTreeRecursive(Agent2D *agent, float &rangeSq, size_t node) const
{
if (agentTree_[node].end - agentTree_[node].begin <= MAX_LEAF_SIZE) {
for (size_t i = agentTree_[node].begin; i < agentTree_[node].end; ++i) {
agent->insertAgentNeighbor(agents_[i], rangeSq);
}
}
else {
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));
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));
if (distSqLeft < distSqRight) {
if (distSqLeft < rangeSq) {
queryAgentTreeRecursive(agent, rangeSq, agentTree_[node].left);
if (distSqRight < rangeSq) {
queryAgentTreeRecursive(agent, rangeSq, agentTree_[node].right);
}
}
}
else {
if (distSqRight < rangeSq) {
queryAgentTreeRecursive(agent, rangeSq, agentTree_[node].right);
if (distSqLeft < rangeSq) {
queryAgentTreeRecursive(agent, rangeSq, agentTree_[node].left);
}
}
}
}
}
void KdTree2D::queryObstacleTreeRecursive(Agent2D *agent, float rangeSq, const ObstacleTreeNode *node) const
{
if (node == NULL) {
return;
}
else {
const Obstacle2D *const obstacle1 = node->obstacle;
const Obstacle2D *const obstacle2 = obstacle1->nextObstacle_;
const float agentLeftOfLine = leftOf(obstacle1->point_, obstacle2->point_, agent->position_);
queryObstacleTreeRecursive(agent, rangeSq, (agentLeftOfLine >= 0.0f ? node->left : node->right));
const float distSqLine = sqr(agentLeftOfLine) / absSq(obstacle2->point_ - obstacle1->point_);
if (distSqLine < rangeSq) {
if (agentLeftOfLine < 0.0f) {
/*
* Try obstacle at this node only if agent is on right side of
* obstacle (and can see obstacle).
*/
agent->insertObstacleNeighbor(node->obstacle, rangeSq);
}
/* Try other side of line. */
queryObstacleTreeRecursive(agent, rangeSq, (agentLeftOfLine >= 0.0f ? node->right : node->left));
}
}
}
bool KdTree2D::queryVisibility(const Vector2 &q1, const Vector2 &q2, float radius) const
{
return queryVisibilityRecursive(q1, q2, radius, obstacleTree_);
}
bool KdTree2D::queryVisibilityRecursive(const Vector2 &q1, const Vector2 &q2, float radius, const ObstacleTreeNode *node) const
{
if (node == NULL) {
return true;
}
else {
const Obstacle2D *const obstacle1 = node->obstacle;
const Obstacle2D *const obstacle2 = obstacle1->nextObstacle_;
const float q1LeftOfI = leftOf(obstacle1->point_, obstacle2->point_, q1);
const float q2LeftOfI = leftOf(obstacle1->point_, obstacle2->point_, q2);
const float invLengthI = 1.0f / absSq(obstacle2->point_ - obstacle1->point_);
if (q1LeftOfI >= 0.0f && q2LeftOfI >= 0.0f) {
return queryVisibilityRecursive(q1, q2, radius, node->left) && ((sqr(q1LeftOfI) * invLengthI >= sqr(radius) && sqr(q2LeftOfI) * invLengthI >= sqr(radius)) || queryVisibilityRecursive(q1, q2, radius, node->right));
}
else if (q1LeftOfI <= 0.0f && q2LeftOfI <= 0.0f) {
return queryVisibilityRecursive(q1, q2, radius, node->right) && ((sqr(q1LeftOfI) * invLengthI >= sqr(radius) && sqr(q2LeftOfI) * invLengthI >= sqr(radius)) || queryVisibilityRecursive(q1, q2, radius, node->left));
}
else if (q1LeftOfI >= 0.0f && q2LeftOfI <= 0.0f) {
/* One can see through obstacle from left to right. */
return queryVisibilityRecursive(q1, q2, radius, node->left) && queryVisibilityRecursive(q1, q2, radius, node->right);
}
else {
const float point1LeftOfQ = leftOf(q1, q2, obstacle1->point_);
const float point2LeftOfQ = leftOf(q1, q2, obstacle2->point_);
const float invLengthQ = 1.0f / absSq(q2 - q1);
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));
}
}
}
}