virtualx-engine/thirdparty/rvo2/rvo2_2d/KdTree2d.cc
2023-06-13 21:13:21 -03:00

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/*
* KdTree2d.cpp
* RVO2 Library
*
* SPDX-FileCopyrightText: 2008 University of North Carolina at Chapel Hill
* SPDX-License-Identifier: Apache-2.0
*
* 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
*
* https://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
*
* <https://gamma.cs.unc.edu/RVO2/>
*/
/**
* @file KdTree2d.cpp
* @brief Defines the KdTree2D class.
*/
#include "KdTree2d.h"
#include <algorithm>
#include <utility>
#include "Agent2d.h"
#include "Obstacle2d.h"
#include "RVOSimulator2d.h"
#include "Vector2.h"
namespace RVO2D {
namespace {
/**
* @relates KdTree2D
* @brief The maximum k-D tree node leaf size.
*/
const std::size_t RVO_MAX_LEAF_SIZE = 10U;
} /* namespace */
/**
* @brief Defines an agent k-D tree node.
*/
class KdTree2D::AgentTreeNode {
public:
/**
* @brief Constructs an agent k-D tree node instance.
*/
AgentTreeNode();
/**
* @brief The beginning node number.
*/
std::size_t begin;
/**
* @brief The ending node number.
*/
std::size_t end;
/**
* @brief The left node number.
*/
std::size_t left;
/**
* @brief The right node number.
*/
std::size_t right;
/**
* @brief The maximum x-coordinate.
*/
float maxX;
/**
* @brief The maximum y-coordinate.
*/
float maxY;
/**
* @brief The minimum x-coordinate.
*/
float minX;
/**
* @brief The minimum y-coordinate.
*/
float minY;
};
KdTree2D::AgentTreeNode::AgentTreeNode()
: begin(0U),
end(0U),
left(0U),
right(0U),
maxX(0.0F),
maxY(0.0F),
minX(0.0F),
minY(0.0F) {}
/**
* @brief Defines an obstacle k-D tree node.
*/
class KdTree2D::ObstacleTreeNode {
public:
/**
* @brief Constructs an obstacle k-D tree node instance.
*/
ObstacleTreeNode();
/**
* @brief Destroys this obstacle k-D tree node instance.
*/
~ObstacleTreeNode();
/**
* @brief The obstacle number.
*/
const Obstacle2D *obstacle;
/**
* @brief The left obstacle tree node.
*/
ObstacleTreeNode *left;
/**
* @brief The right obstacle tree node.
*/
ObstacleTreeNode *right;
private:
/* Not implemented. */
ObstacleTreeNode(const ObstacleTreeNode &other);
/* Not implemented. */
ObstacleTreeNode &operator=(const ObstacleTreeNode &other);
};
KdTree2D::ObstacleTreeNode::ObstacleTreeNode()
: obstacle(NULL), left(NULL), right(NULL) {}
KdTree2D::ObstacleTreeNode::~ObstacleTreeNode() {}
KdTree2D::KdTree2D(RVOSimulator2D *simulator)
: obstacleTree_(NULL), simulator_(simulator) {}
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(std::size_t begin, std::size_t end,
std::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 (std::size_t i = begin + 1U; 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 > RVO_MAX_LEAF_SIZE) {
/* No leaf node. */
const bool isVertical = agentTree_[node].maxX - agentTree_[node].minX >
agentTree_[node].maxY - agentTree_[node].minY;
const float splitValue =
0.5F * (isVertical ? agentTree_[node].maxX + agentTree_[node].minX
: agentTree_[node].maxY + agentTree_[node].minY);
std::size_t left = begin;
std::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 - 1U]->position_.x()
: agents_[right - 1U]->position_.y()) >= splitValue) {
--right;
}
if (left < right) {
std::swap(agents_[left], agents_[right - 1U]);
++left;
--right;
}
}
if (left == begin) {
++left;
++right;
}
agentTree_[node].left = node + 1U;
agentTree_[node].right = node + 2U * (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()) {
ObstacleTreeNode *const node = new ObstacleTreeNode();
std::size_t optimalSplit = 0U;
std::size_t minLeft = obstacles.size();
std::size_t minRight = obstacles.size();
for (std::size_t i = 0U; i < obstacles.size(); ++i) {
std::size_t leftSize = 0U;
std::size_t rightSize = 0U;
const Obstacle2D *const obstacleI1 = obstacles[i];
const Obstacle2D *const obstacleI2 = obstacleI1->next_;
/* Compute optimal split node. */
for (std::size_t j = 0U; j < obstacles.size(); ++j) {
if (i != j) {
const Obstacle2D *const obstacleJ1 = obstacles[j];
const Obstacle2D *const obstacleJ2 = obstacleJ1->next_;
const float j1LeftOfI = leftOf(obstacleI1->point_, obstacleI2->point_,
obstacleJ1->point_);
const float j2LeftOfI = leftOf(obstacleI1->point_, obstacleI2->point_,
obstacleJ2->point_);
if (j1LeftOfI >= -RVO2D_EPSILON && j2LeftOfI >= -RVO2D_EPSILON) {
++leftSize;
} else if (j1LeftOfI <= RVO2D_EPSILON && j2LeftOfI <= RVO2D_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);
std::size_t leftCounter = 0U;
std::size_t rightCounter = 0U;
const std::size_t i = optimalSplit;
const Obstacle2D *const obstacleI1 = obstacles[i];
const Obstacle2D *const obstacleI2 = obstacleI1->next_;
for (std::size_t j = 0U; j < obstacles.size(); ++j) {
if (i != j) {
Obstacle2D *const obstacleJ1 = obstacles[j];
Obstacle2D *const obstacleJ2 = obstacleJ1->next_;
const float j1LeftOfI =
leftOf(obstacleI1->point_, obstacleI2->point_, obstacleJ1->point_);
const float j2LeftOfI =
leftOf(obstacleI1->point_, obstacleI2->point_, obstacleJ2->point_);
if (j1LeftOfI >= -RVO2D_EPSILON && j2LeftOfI >= -RVO2D_EPSILON) {
leftObstacles[leftCounter++] = obstacles[j];
} else if (j1LeftOfI <= RVO2D_EPSILON && j2LeftOfI <= RVO2D_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->direction_ = obstacleJ1->direction_;
newObstacle->point_ = splitPoint;
newObstacle->next_ = obstacleJ2;
newObstacle->previous_ = obstacleJ1;
newObstacle->id_ = simulator_->obstacles_.size();
newObstacle->isConvex_ = true;
simulator_->obstacles_.push_back(newObstacle);
obstacleJ1->next_ = newObstacle;
obstacleJ2->previous_ = 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;
}
return NULL;
}
void KdTree2D::computeAgentNeighbors(Agent2D *agent, float &rangeSq) const {
queryAgentTreeRecursive(agent, rangeSq, 0U);
}
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,
std::size_t node) const {
if (agentTree_[node].end - agentTree_[node].begin <= RVO_MAX_LEAF_SIZE) {
for (std::size_t i = agentTree_[node].begin; i < agentTree_[node].end;
++i) {
agent->insertAgentNeighbor(agents_[i], rangeSq);
}
} else {
const float distLeftMinX = std::max(
0.0F, agentTree_[agentTree_[node].left].minX - agent->position_.x());
const float distLeftMaxX = std::max(
0.0F, agent->position_.x() - agentTree_[agentTree_[node].left].maxX);
const float distLeftMinY = std::max(
0.0F, agentTree_[agentTree_[node].left].minY - agent->position_.y());
const float distLeftMaxY = std::max(
0.0F, agent->position_.y() - agentTree_[agentTree_[node].left].maxY);
const float distSqLeft =
distLeftMinX * distLeftMinX + distLeftMaxX * distLeftMaxX +
distLeftMinY * distLeftMinY + distLeftMaxY * distLeftMaxY;
const float distRightMinX = std::max(
0.0F, agentTree_[agentTree_[node].right].minX - agent->position_.x());
const float distRightMaxX = std::max(
0.0F, agent->position_.x() - agentTree_[agentTree_[node].right].maxX);
const float distRightMinY = std::max(
0.0F, agentTree_[agentTree_[node].right].minY - agent->position_.y());
const float distRightMaxY = std::max(
0.0F, agent->position_.y() - agentTree_[agentTree_[node].right].maxY);
const float distSqRight =
distRightMinX * distRightMinX + distRightMaxX * distRightMaxX +
distRightMinY * distRightMinY + distRightMaxY * distRightMaxY;
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) {
const Obstacle2D *const obstacle1 = node->obstacle;
const Obstacle2D *const obstacle2 = obstacle1->next_;
const float agentLeftOfLine =
leftOf(obstacle1->point_, obstacle2->point_, agent->position_);
queryObstacleTreeRecursive(
agent, rangeSq, agentLeftOfLine >= 0.0F ? node->left : node->right);
const float distSqLine = agentLeftOfLine * 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 &vector1, const Vector2 &vector2,
float radius) const {
return queryVisibilityRecursive(vector1, vector2, radius, obstacleTree_);
}
bool KdTree2D::queryVisibilityRecursive(const Vector2 &vector1,
const Vector2 &vector2, float radius,
const ObstacleTreeNode *node) const {
if (node != NULL) {
const Obstacle2D *const obstacle1 = node->obstacle;
const Obstacle2D *const obstacle2 = obstacle1->next_;
const float q1LeftOfI =
leftOf(obstacle1->point_, obstacle2->point_, vector1);
const float q2LeftOfI =
leftOf(obstacle1->point_, obstacle2->point_, vector2);
const float invLengthI =
1.0F / absSq(obstacle2->point_ - obstacle1->point_);
if (q1LeftOfI >= 0.0F && q2LeftOfI >= 0.0F) {
return queryVisibilityRecursive(vector1, vector2, radius, node->left) &&
((q1LeftOfI * q1LeftOfI * invLengthI >= radius * radius &&
q2LeftOfI * q2LeftOfI * invLengthI >= radius * radius) ||
queryVisibilityRecursive(vector1, vector2, radius, node->right));
}
if (q1LeftOfI <= 0.0F && q2LeftOfI <= 0.0F) {
return queryVisibilityRecursive(vector1, vector2, radius, node->right) &&
((q1LeftOfI * q1LeftOfI * invLengthI >= radius * radius &&
q2LeftOfI * q2LeftOfI * invLengthI >= radius * radius) ||
queryVisibilityRecursive(vector1, vector2, radius, node->left));
}
if (q1LeftOfI >= 0.0F && q2LeftOfI <= 0.0F) {
/* One can see through obstacle from left to right. */
return queryVisibilityRecursive(vector1, vector2, radius, node->left) &&
queryVisibilityRecursive(vector1, vector2, radius, node->right);
}
const float point1LeftOfQ = leftOf(vector1, vector2, obstacle1->point_);
const float point2LeftOfQ = leftOf(vector1, vector2, obstacle2->point_);
const float invLengthQ = 1.0F / absSq(vector2 - vector1);
return point1LeftOfQ * point2LeftOfQ >= 0.0F &&
point1LeftOfQ * point1LeftOfQ * invLengthQ > radius * radius &&
point2LeftOfQ * point2LeftOfQ * invLengthQ > radius * radius &&
queryVisibilityRecursive(vector1, vector2, radius, node->left) &&
queryVisibilityRecursive(vector1, vector2, radius, node->right);
}
return true;
}
} /* namespace RVO2D */