virtualx-engine/thirdparty/rvo2/rvo2_2d/Agent2d.cc
2023-06-13 21:13:21 -03:00

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C++

/*
* Agent2d.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 Agent2d.cpp
* @brief Defines the Agent2D class.
*/
#include "Agent2d.h"
#include <algorithm>
#include <cmath>
#include <limits>
#include "KdTree2d.h"
#include "Obstacle2d.h"
namespace RVO2D {
namespace {
/**
* @relates Agent2D
* @brief Solves a one-dimensional linear program on a specified line
* subject to linear constraints defined by lines and a circular
* constraint.
* @param[in] lines Lines defining the linear constraints.
* @param[in] lineNo The specified line constraint.
* @param[in] radius The radius of the circular constraint.
* @param[in] optVelocity The optimization velocity.
* @param[in] directionOpt True if the direction should be optimized.
* @param[in, out] result A reference to the result of the linear program.
* @return True if successful.
*/
bool linearProgram1(const std::vector<Line> &lines, std::size_t lineNo,
float radius, const Vector2 &optVelocity, bool directionOpt,
Vector2 &result) { /* NOLINT(runtime/references) */
const float dotProduct = lines[lineNo].point * lines[lineNo].direction;
const float discriminant =
dotProduct * dotProduct + radius * radius - absSq(lines[lineNo].point);
if (discriminant < 0.0F) {
/* Max speed circle fully invalidates line lineNo. */
return false;
}
const float sqrtDiscriminant = std::sqrt(discriminant);
float tLeft = -dotProduct - sqrtDiscriminant;
float tRight = -dotProduct + sqrtDiscriminant;
for (std::size_t i = 0U; i < lineNo; ++i) {
const float denominator = det(lines[lineNo].direction, lines[i].direction);
const float numerator =
det(lines[i].direction, lines[lineNo].point - lines[i].point);
if (std::fabs(denominator) <= RVO2D_EPSILON) {
/* Lines lineNo and i are (almost) parallel. */
if (numerator < 0.0F) {
return false;
}
continue;
}
const float t = numerator / denominator;
if (denominator >= 0.0F) {
/* Line i bounds line lineNo on the right. */
tRight = std::min(tRight, t);
} else {
/* Line i bounds line lineNo on the left. */
tLeft = std::max(tLeft, t);
}
if (tLeft > tRight) {
return false;
}
}
if (directionOpt) {
/* Optimize direction. */
if (optVelocity * lines[lineNo].direction > 0.0F) {
/* Take right extreme. */
result = lines[lineNo].point + tRight * lines[lineNo].direction;
} else {
/* Take left extreme. */
result = lines[lineNo].point + tLeft * lines[lineNo].direction;
}
} else {
/* Optimize closest point. */
const float t =
lines[lineNo].direction * (optVelocity - lines[lineNo].point);
if (t < tLeft) {
result = lines[lineNo].point + tLeft * lines[lineNo].direction;
} else if (t > tRight) {
result = lines[lineNo].point + tRight * lines[lineNo].direction;
} else {
result = lines[lineNo].point + t * lines[lineNo].direction;
}
}
return true;
}
/**
* @relates Agent2D
* @brief Solves a two-dimensional linear program subject to linear
* constraints defined by lines and a circular constraint.
* @param[in] lines Lines defining the linear constraints.
* @param[in] radius The radius of the circular constraint.
* @param[in] optVelocity The optimization velocity.
* @param[in] directionOpt True if the direction should be optimized.
* @param[in, out] result A reference to the result of the linear program.
* @return The number of the line it fails on, and the number of lines
* if successful.
*/
std::size_t linearProgram2(const std::vector<Line> &lines, float radius,
const Vector2 &optVelocity, bool directionOpt,
Vector2 &result) { /* NOLINT(runtime/references) */
if (directionOpt) {
/* Optimize direction. Note that the optimization velocity is of unit length
* in this case.
*/
result = optVelocity * radius;
} else if (absSq(optVelocity) > radius * radius) {
/* Optimize closest point and outside circle. */
result = normalize(optVelocity) * radius;
} else {
/* Optimize closest point and inside circle. */
result = optVelocity;
}
for (std::size_t i = 0U; i < lines.size(); ++i) {
if (det(lines[i].direction, lines[i].point - result) > 0.0F) {
/* Result does not satisfy constraint i. Compute new optimal result. */
const Vector2 tempResult = result;
if (!linearProgram1(lines, i, radius, optVelocity, directionOpt,
result)) {
result = tempResult;
return i;
}
}
}
return lines.size();
}
/**
* @relates Agent2D
* @brief Solves a two-dimensional linear program subject to linear
* constraints defined by lines and a circular constraint.
* @param[in] lines Lines defining the linear constraints.
* @param[in] numObstLines Count of obstacle lines.
* @param[in] beginLine The line on which the 2-d linear program failed.
* @param[in] radius The radius of the circular constraint.
* @param[in, out] result A reference to the result of the linear program.
*/
void linearProgram3(const std::vector<Line> &lines, std::size_t numObstLines,
std::size_t beginLine, float radius,
Vector2 &result) { /* NOLINT(runtime/references) */
float distance = 0.0F;
for (std::size_t i = beginLine; i < lines.size(); ++i) {
if (det(lines[i].direction, lines[i].point - result) > distance) {
/* Result does not satisfy constraint of line i. */
std::vector<Line> projLines(
lines.begin(),
lines.begin() + static_cast<std::ptrdiff_t>(numObstLines));
for (std::size_t j = numObstLines; j < i; ++j) {
Line line;
const float determinant = det(lines[i].direction, lines[j].direction);
if (std::fabs(determinant) <= RVO2D_EPSILON) {
/* Line i and line j are parallel. */
if (lines[i].direction * lines[j].direction > 0.0F) {
/* Line i and line j point in the same direction. */
continue;
}
/* Line i and line j point in opposite direction. */
line.point = 0.5F * (lines[i].point + lines[j].point);
} else {
line.point = lines[i].point + (det(lines[j].direction,
lines[i].point - lines[j].point) /
determinant) *
lines[i].direction;
}
line.direction = normalize(lines[j].direction - lines[i].direction);
projLines.push_back(line);
}
const Vector2 tempResult = result;
if (linearProgram2(
projLines, radius,
Vector2(-lines[i].direction.y(), lines[i].direction.x()), true,
result) < projLines.size()) {
/* This should in principle not happen. The result is by definition
* already in the feasible region of this linear program. If it fails,
* it is due to small floating point error, and the current result is
* kept. */
result = tempResult;
}
distance = det(lines[i].direction, lines[i].point - result);
}
}
}
} /* namespace */
Agent2D::Agent2D()
: id_(0U),
maxNeighbors_(0U),
maxSpeed_(0.0F),
neighborDist_(0.0F),
radius_(0.0F),
timeHorizon_(0.0F),
timeHorizonObst_(0.0F) {}
Agent2D::~Agent2D() {}
void Agent2D::computeNeighbors(const KdTree2D *kdTree) {
obstacleNeighbors_.clear();
const float range = timeHorizonObst_ * maxSpeed_ + radius_;
kdTree->computeObstacleNeighbors(this, range * range);
agentNeighbors_.clear();
if (maxNeighbors_ > 0U) {
float rangeSq = neighborDist_ * neighborDist_;
kdTree->computeAgentNeighbors(this, rangeSq);
}
}
/* Search for the best new velocity. */
void Agent2D::computeNewVelocity(float timeStep) {
orcaLines_.clear();
const float invTimeHorizonObst = 1.0F / timeHorizonObst_;
/* Create obstacle ORCA lines. */
for (std::size_t i = 0U; i < obstacleNeighbors_.size(); ++i) {
const Obstacle2D *obstacle1 = obstacleNeighbors_[i].second;
const Obstacle2D *obstacle2 = obstacle1->next_;
const Vector2 relativePosition1 = obstacle1->point_ - position_;
const Vector2 relativePosition2 = obstacle2->point_ - position_;
/* Check if velocity obstacle of obstacle is already taken care of by
* previously constructed obstacle ORCA lines. */
bool alreadyCovered = false;
for (std::size_t j = 0U; j < orcaLines_.size(); ++j) {
if (det(invTimeHorizonObst * relativePosition1 - orcaLines_[j].point,
orcaLines_[j].direction) -
invTimeHorizonObst * radius_ >=
-RVO2D_EPSILON &&
det(invTimeHorizonObst * relativePosition2 - orcaLines_[j].point,
orcaLines_[j].direction) -
invTimeHorizonObst * radius_ >=
-RVO2D_EPSILON) {
alreadyCovered = true;
break;
}
}
if (alreadyCovered) {
continue;
}
/* Not yet covered. Check for collisions. */
const float distSq1 = absSq(relativePosition1);
const float distSq2 = absSq(relativePosition2);
const float radiusSq = radius_ * radius_;
const Vector2 obstacleVector = obstacle2->point_ - obstacle1->point_;
const float s =
(-relativePosition1 * obstacleVector) / absSq(obstacleVector);
const float distSqLine = absSq(-relativePosition1 - s * obstacleVector);
Line line;
if (s < 0.0F && distSq1 <= radiusSq) {
/* Collision with left vertex. Ignore if non-convex. */
if (obstacle1->isConvex_) {
line.point = Vector2(0.0F, 0.0F);
line.direction =
normalize(Vector2(-relativePosition1.y(), relativePosition1.x()));
orcaLines_.push_back(line);
}
continue;
}
if (s > 1.0F && distSq2 <= radiusSq) {
/* Collision with right vertex. Ignore if non-convex or if it will be
* taken care of by neighoring obstace */
if (obstacle2->isConvex_ &&
det(relativePosition2, obstacle2->direction_) >= 0.0F) {
line.point = Vector2(0.0F, 0.0F);
line.direction =
normalize(Vector2(-relativePosition2.y(), relativePosition2.x()));
orcaLines_.push_back(line);
}
continue;
}
if (s >= 0.0F && s <= 1.0F && distSqLine <= radiusSq) {
/* Collision with obstacle segment. */
line.point = Vector2(0.0F, 0.0F);
line.direction = -obstacle1->direction_;
orcaLines_.push_back(line);
continue;
}
/* No collision. Compute legs. When obliquely viewed, both legs can come
* from a single vertex. Legs extend cut-off line when nonconvex vertex. */
Vector2 leftLegDirection;
Vector2 rightLegDirection;
if (s < 0.0F && distSqLine <= radiusSq) {
/* Obstacle2D viewed obliquely so that left vertex defines velocity
* obstacle. */
if (!obstacle1->isConvex_) {
/* Ignore obstacle. */
continue;
}
obstacle2 = obstacle1;
const float leg1 = std::sqrt(distSq1 - radiusSq);
leftLegDirection =
Vector2(
relativePosition1.x() * leg1 - relativePosition1.y() * radius_,
relativePosition1.x() * radius_ + relativePosition1.y() * leg1) /
distSq1;
rightLegDirection =
Vector2(
relativePosition1.x() * leg1 + relativePosition1.y() * radius_,
-relativePosition1.x() * radius_ + relativePosition1.y() * leg1) /
distSq1;
} else if (s > 1.0F && distSqLine <= radiusSq) {
/* Obstacle2D viewed obliquely so that right vertex defines velocity
* obstacle. */
if (!obstacle2->isConvex_) {
/* Ignore obstacle. */
continue;
}
obstacle1 = obstacle2;
const float leg2 = std::sqrt(distSq2 - radiusSq);
leftLegDirection =
Vector2(
relativePosition2.x() * leg2 - relativePosition2.y() * radius_,
relativePosition2.x() * radius_ + relativePosition2.y() * leg2) /
distSq2;
rightLegDirection =
Vector2(
relativePosition2.x() * leg2 + relativePosition2.y() * radius_,
-relativePosition2.x() * radius_ + relativePosition2.y() * leg2) /
distSq2;
} else {
/* Usual situation. */
if (obstacle1->isConvex_) {
const float leg1 = std::sqrt(distSq1 - radiusSq);
leftLegDirection = Vector2(relativePosition1.x() * leg1 -
relativePosition1.y() * radius_,
relativePosition1.x() * radius_ +
relativePosition1.y() * leg1) /
distSq1;
} else {
/* Left vertex non-convex; left leg extends cut-off line. */
leftLegDirection = -obstacle1->direction_;
}
if (obstacle2->isConvex_) {
const float leg2 = std::sqrt(distSq2 - radiusSq);
rightLegDirection = Vector2(relativePosition2.x() * leg2 +
relativePosition2.y() * radius_,
-relativePosition2.x() * radius_ +
relativePosition2.y() * leg2) /
distSq2;
} else {
/* Right vertex non-convex; right leg extends cut-off line. */
rightLegDirection = obstacle1->direction_;
}
}
/* Legs can never point into neighboring edge when convex vertex, take
* cutoff-line of neighboring edge instead. If velocity projected on
* "foreign" leg, no constraint is added. */
const Obstacle2D *const leftNeighbor = obstacle1->previous_;
bool isLeftLegForeign = false;
bool isRightLegForeign = false;
if (obstacle1->isConvex_ &&
det(leftLegDirection, -leftNeighbor->direction_) >= 0.0F) {
/* Left leg points into obstacle. */
leftLegDirection = -leftNeighbor->direction_;
isLeftLegForeign = true;
}
if (obstacle2->isConvex_ &&
det(rightLegDirection, obstacle2->direction_) <= 0.0F) {
/* Right leg points into obstacle. */
rightLegDirection = obstacle2->direction_;
isRightLegForeign = true;
}
/* Compute cut-off centers. */
const Vector2 leftCutoff =
invTimeHorizonObst * (obstacle1->point_ - position_);
const Vector2 rightCutoff =
invTimeHorizonObst * (obstacle2->point_ - position_);
const Vector2 cutoffVector = rightCutoff - leftCutoff;
/* Project current velocity on velocity obstacle. */
/* Check if current velocity is projected on cutoff circles. */
const float t =
obstacle1 == obstacle2
? 0.5F
: (velocity_ - leftCutoff) * cutoffVector / absSq(cutoffVector);
const float tLeft = (velocity_ - leftCutoff) * leftLegDirection;
const float tRight = (velocity_ - rightCutoff) * rightLegDirection;
if ((t < 0.0F && tLeft < 0.0F) ||
(obstacle1 == obstacle2 && tLeft < 0.0F && tRight < 0.0F)) {
/* Project on left cut-off circle. */
const Vector2 unitW = normalize(velocity_ - leftCutoff);
line.direction = Vector2(unitW.y(), -unitW.x());
line.point = leftCutoff + radius_ * invTimeHorizonObst * unitW;
orcaLines_.push_back(line);
continue;
}
if (t > 1.0F && tRight < 0.0F) {
/* Project on right cut-off circle. */
const Vector2 unitW = normalize(velocity_ - rightCutoff);
line.direction = Vector2(unitW.y(), -unitW.x());
line.point = rightCutoff + radius_ * invTimeHorizonObst * unitW;
orcaLines_.push_back(line);
continue;
}
/* Project on left leg, right leg, or cut-off line, whichever is closest to
* velocity. */
const float distSqCutoff =
(t < 0.0F || t > 1.0F || obstacle1 == obstacle2)
? std::numeric_limits<float>::infinity()
: absSq(velocity_ - (leftCutoff + t * cutoffVector));
const float distSqLeft =
tLeft < 0.0F
? std::numeric_limits<float>::infinity()
: absSq(velocity_ - (leftCutoff + tLeft * leftLegDirection));
const float distSqRight =
tRight < 0.0F
? std::numeric_limits<float>::infinity()
: absSq(velocity_ - (rightCutoff + tRight * rightLegDirection));
if (distSqCutoff <= distSqLeft && distSqCutoff <= distSqRight) {
/* Project on cut-off line. */
line.direction = -obstacle1->direction_;
line.point =
leftCutoff + radius_ * invTimeHorizonObst *
Vector2(-line.direction.y(), line.direction.x());
orcaLines_.push_back(line);
continue;
}
if (distSqLeft <= distSqRight) {
/* Project on left leg. */
if (isLeftLegForeign) {
continue;
}
line.direction = leftLegDirection;
line.point =
leftCutoff + radius_ * invTimeHorizonObst *
Vector2(-line.direction.y(), line.direction.x());
orcaLines_.push_back(line);
continue;
}
/* Project on right leg. */
if (isRightLegForeign) {
continue;
}
line.direction = -rightLegDirection;
line.point =
rightCutoff + radius_ * invTimeHorizonObst *
Vector2(-line.direction.y(), line.direction.x());
orcaLines_.push_back(line);
}
const std::size_t numObstLines = orcaLines_.size();
const float invTimeHorizon = 1.0F / timeHorizon_;
/* Create agent ORCA lines. */
for (std::size_t i = 0U; i < agentNeighbors_.size(); ++i) {
const Agent2D *const other = agentNeighbors_[i].second;
const Vector2 relativePosition = other->position_ - position_;
const Vector2 relativeVelocity = velocity_ - other->velocity_;
const float distSq = absSq(relativePosition);
const float combinedRadius = radius_ + other->radius_;
const float combinedRadiusSq = combinedRadius * combinedRadius;
Line line;
Vector2 u;
if (distSq > combinedRadiusSq) {
/* No collision. */
const Vector2 w = relativeVelocity - invTimeHorizon * relativePosition;
/* Vector from cutoff center to relative velocity. */
const float wLengthSq = absSq(w);
const float dotProduct = w * relativePosition;
if (dotProduct < 0.0F &&
dotProduct * dotProduct > combinedRadiusSq * wLengthSq) {
/* Project on cut-off circle. */
const float wLength = std::sqrt(wLengthSq);
const Vector2 unitW = w / wLength;
line.direction = Vector2(unitW.y(), -unitW.x());
u = (combinedRadius * invTimeHorizon - wLength) * unitW;
} else {
/* Project on legs. */
const float leg = std::sqrt(distSq - combinedRadiusSq);
if (det(relativePosition, w) > 0.0F) {
/* Project on left leg. */
line.direction = Vector2(relativePosition.x() * leg -
relativePosition.y() * combinedRadius,
relativePosition.x() * combinedRadius +
relativePosition.y() * leg) /
distSq;
} else {
/* Project on right leg. */
line.direction = -Vector2(relativePosition.x() * leg +
relativePosition.y() * combinedRadius,
-relativePosition.x() * combinedRadius +
relativePosition.y() * leg) /
distSq;
}
u = (relativeVelocity * line.direction) * line.direction -
relativeVelocity;
}
} else {
/* Collision. Project on cut-off circle of time timeStep. */
const float invTimeStep = 1.0F / timeStep;
/* Vector from cutoff center to relative velocity. */
const Vector2 w = relativeVelocity - invTimeStep * relativePosition;
const float wLength = abs(w);
const Vector2 unitW = w / wLength;
line.direction = Vector2(unitW.y(), -unitW.x());
u = (combinedRadius * invTimeStep - wLength) * unitW;
}
line.point = velocity_ + 0.5F * u;
orcaLines_.push_back(line);
}
const std::size_t lineFail =
linearProgram2(orcaLines_, maxSpeed_, prefVelocity_, false, newVelocity_);
if (lineFail < orcaLines_.size()) {
linearProgram3(orcaLines_, numObstLines, lineFail, maxSpeed_, newVelocity_);
}
}
void Agent2D::insertAgentNeighbor(const Agent2D *agent, float &rangeSq) {
// no point processing same agent
if (this == agent) {
return;
}
// ignore other agent if layers/mask bitmasks have no matching bit
if ((avoidance_mask_ & agent->avoidance_layers_) == 0) {
return;
}
// ignore other agent if this agent is below or above
if ((elevation_ > agent->elevation_ + agent->height_) || (elevation_ + height_ < agent->elevation_)) {
return;
}
if (avoidance_priority_ > agent->avoidance_priority_) {
return;
}
const float distSq = absSq(position_ - agent->position_);
if (distSq < rangeSq) {
if (agentNeighbors_.size() < maxNeighbors_) {
agentNeighbors_.push_back(std::make_pair(distSq, agent));
}
std::size_t i = agentNeighbors_.size() - 1U;
while (i != 0U && distSq < agentNeighbors_[i - 1U].first) {
agentNeighbors_[i] = agentNeighbors_[i - 1U];
--i;
}
agentNeighbors_[i] = std::make_pair(distSq, agent);
if (agentNeighbors_.size() == maxNeighbors_) {
rangeSq = agentNeighbors_.back().first;
}
}
}
void Agent2D::insertObstacleNeighbor(const Obstacle2D *obstacle, float rangeSq) {
const Obstacle2D *const nextObstacle = obstacle->next_;
float distSq = 0.0F;
const float r = ((position_ - obstacle->point_) *
(nextObstacle->point_ - obstacle->point_)) /
absSq(nextObstacle->point_ - obstacle->point_);
if (r < 0.0F) {
distSq = absSq(position_ - obstacle->point_);
} else if (r > 1.0F) {
distSq = absSq(position_ - nextObstacle->point_);
} else {
distSq = absSq(position_ - (obstacle->point_ +
r * (nextObstacle->point_ - obstacle->point_)));
}
if (distSq < rangeSq) {
obstacleNeighbors_.push_back(std::make_pair(distSq, obstacle));
std::size_t i = obstacleNeighbors_.size() - 1U;
while (i != 0U && distSq < obstacleNeighbors_[i - 1U].first) {
obstacleNeighbors_[i] = obstacleNeighbors_[i - 1U];
--i;
}
obstacleNeighbors_[i] = std::make_pair(distSq, obstacle);
}
}
void Agent2D::update(float timeStep) {
velocity_ = newVelocity_;
position_ += velocity_ * timeStep;
}
} /* namespace RVO2D */