virtualx-engine/thirdparty/rvo2/rvo2_3d/KdTree3d.cc
2023-06-13 21:13:21 -03:00

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8.2 KiB
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/*
* KdTree3d.cc
* RVO2-3D 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/>
*/
#include "KdTree3d.h"
#include <algorithm>
#include <utility>
#include "Agent3d.h"
#include "RVOSimulator3d.h"
#include "Vector3.h"
namespace RVO3D {
namespace {
/**
* @brief The maximum size of a k-D leaf node.
*/
const std::size_t RVO3D_MAX_LEAF_SIZE = 10U;
} /* namespace */
/**
* @brief Defines an agent k-D tree node.
*/
class KdTree3D::AgentTreeNode {
public:
/**
* @brief Constructs an agent k-D tree node.
*/
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 coordinates.
*/
Vector3 maxCoord;
/**
* @brief The minimum coordinates.
*/
Vector3 minCoord;
};
KdTree3D::AgentTreeNode::AgentTreeNode()
: begin(0U), end(0U), left(0U), right(0U) {}
KdTree3D::KdTree3D(RVOSimulator3D *sim) : sim_(sim) {}
KdTree3D::~KdTree3D() {}
void KdTree3D::buildAgentTree(std::vector<Agent3D *> agents) {
agents_.swap(agents_);
if (!agents_.empty()) {
agentTree_.resize(2U * agents_.size() - 1U);
buildAgentTreeRecursive(0U, agents_.size(), 0U);
}
}
void KdTree3D::buildAgentTreeRecursive(std::size_t begin, std::size_t end,
std::size_t node) {
agentTree_[node].begin = begin;
agentTree_[node].end = end;
agentTree_[node].minCoord = agents_[begin]->position_;
agentTree_[node].maxCoord = agents_[begin]->position_;
for (std::size_t i = begin + 1U; i < end; ++i) {
agentTree_[node].maxCoord[0] =
std::max(agentTree_[node].maxCoord[0], agents_[i]->position_.x());
agentTree_[node].minCoord[0] =
std::min(agentTree_[node].minCoord[0], agents_[i]->position_.x());
agentTree_[node].maxCoord[1] =
std::max(agentTree_[node].maxCoord[1], agents_[i]->position_.y());
agentTree_[node].minCoord[1] =
std::min(agentTree_[node].minCoord[1], agents_[i]->position_.y());
agentTree_[node].maxCoord[2] =
std::max(agentTree_[node].maxCoord[2], agents_[i]->position_.z());
agentTree_[node].minCoord[2] =
std::min(agentTree_[node].minCoord[2], agents_[i]->position_.z());
}
if (end - begin > RVO3D_MAX_LEAF_SIZE) {
/* No leaf node. */
std::size_t coord = 0U;
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]) {
coord = 0U;
} else if (agentTree_[node].maxCoord[1] - agentTree_[node].minCoord[1] >
agentTree_[node].maxCoord[2] - agentTree_[node].minCoord[2]) {
coord = 1U;
} else {
coord = 2U;
}
const float splitValue = 0.5F * (agentTree_[node].maxCoord[coord] +
agentTree_[node].minCoord[coord]);
std::size_t left = begin;
std::size_t right = end;
while (left < right) {
while (left < right && agents_[left]->position_[coord] < splitValue) {
++left;
}
while (right > left &&
agents_[right - 1U]->position_[coord] >= splitValue) {
--right;
}
if (left < right) {
std::swap(agents_[left], agents_[right - 1U]);
++left;
--right;
}
}
std::size_t leftSize = left - begin;
if (leftSize == 0U) {
++leftSize;
++left;
}
agentTree_[node].left = node + 1U;
agentTree_[node].right = node + 2U * leftSize;
buildAgentTreeRecursive(begin, left, agentTree_[node].left);
buildAgentTreeRecursive(left, end, agentTree_[node].right);
}
}
void KdTree3D::computeAgentNeighbors(Agent3D *agent, float rangeSq) const {
queryAgentTreeRecursive(agent, rangeSq, 0U);
}
void KdTree3D::queryAgentTreeRecursive(Agent3D *agent, float &rangeSq,
std::size_t node) const {
if (agentTree_[node].end - agentTree_[node].begin <= RVO3D_MAX_LEAF_SIZE) {
for (std::size_t i = agentTree_[node].begin; i < agentTree_[node].end;
++i) {
agent->insertAgentNeighbor(agents_[i], rangeSq);
}
} else {
const float distSqLeftMinX =
std::max(0.0F, agentTree_[agentTree_[node].left].minCoord[0] -
agent->position_.x());
const float distSqLeftMaxX =
std::max(0.0F, agent->position_.x() -
agentTree_[agentTree_[node].left].maxCoord[0]);
const float distSqLeftMinY =
std::max(0.0F, agentTree_[agentTree_[node].left].minCoord[1] -
agent->position_.y());
const float distSqLeftMaxY =
std::max(0.0F, agent->position_.y() -
agentTree_[agentTree_[node].left].maxCoord[1]);
const float distSqLeftMinZ =
std::max(0.0F, agentTree_[agentTree_[node].left].minCoord[2] -
agent->position_.z());
const float distSqLeftMaxZ =
std::max(0.0F, agent->position_.z() -
agentTree_[agentTree_[node].left].maxCoord[2]);
const float distSqLeft =
distSqLeftMinX * distSqLeftMinX + distSqLeftMaxX * distSqLeftMaxX +
distSqLeftMinY * distSqLeftMinY + distSqLeftMaxY * distSqLeftMaxY +
distSqLeftMinZ * distSqLeftMinZ + distSqLeftMaxZ * distSqLeftMaxZ;
const float distSqRightMinX =
std::max(0.0F, agentTree_[agentTree_[node].right].minCoord[0] -
agent->position_.x());
const float distSqRightMaxX =
std::max(0.0F, agent->position_.x() -
agentTree_[agentTree_[node].right].maxCoord[0]);
const float distSqRightMinY =
std::max(0.0F, agentTree_[agentTree_[node].right].minCoord[1] -
agent->position_.y());
const float distSqRightMaxY =
std::max(0.0F, agent->position_.y() -
agentTree_[agentTree_[node].right].maxCoord[1]);
const float distSqRightMinZ =
std::max(0.0F, agentTree_[agentTree_[node].right].minCoord[2] -
agent->position_.z());
const float distSqRightMaxZ =
std::max(0.0F, agent->position_.z() -
agentTree_[agentTree_[node].right].maxCoord[2]);
const float distSqRight =
distSqRightMinX * distSqRightMinX + distSqRightMaxX * distSqRightMaxX +
distSqRightMinY * distSqRightMinY + distSqRightMaxY * distSqRightMaxY +
distSqRightMinZ * distSqRightMinZ + distSqRightMaxZ * distSqRightMaxZ;
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);
}
}
}
}
}
} /* namespace RVO3D */