virtualx-engine/thirdparty/rvo2/rvo2_2d/Agent2d.cpp

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/*
* Agent2d.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 "Agent2d.h"
#include "KdTree2d.h"
#include "Obstacle2d.h"
namespace RVO2D {
Agent2D::Agent2D() : maxNeighbors_(0), maxSpeed_(0.0f), neighborDist_(0.0f), radius_(0.0f), timeHorizon_(0.0f), timeHorizonObst_(0.0f), id_(0) { }
void Agent2D::computeNeighbors(RVOSimulator2D *sim_)
{
obstacleNeighbors_.clear();
float rangeSq = sqr(timeHorizonObst_ * maxSpeed_ + radius_);
sim_->kdTree_->computeObstacleNeighbors(this, rangeSq);
agentNeighbors_.clear();
if (maxNeighbors_ > 0) {
rangeSq = sqr(neighborDist_);
sim_->kdTree_->computeAgentNeighbors(this, rangeSq);
}
}
/* Search for the best new velocity. */
void Agent2D::computeNewVelocity(RVOSimulator2D *sim_)
{
orcaLines_.clear();
const float invTimeHorizonObst = 1.0f / timeHorizonObst_;
/* Create obstacle ORCA lines. */
for (size_t i = 0; i < obstacleNeighbors_.size(); ++i) {
const Obstacle2D *obstacle1 = obstacleNeighbors_[i].second;
const Obstacle2D *obstacle2 = obstacle1->nextObstacle_;
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 (size_t j = 0; j < orcaLines_.size(); ++j) {
if (det(invTimeHorizonObst * relativePosition1 - orcaLines_[j].point, orcaLines_[j].direction) - invTimeHorizonObst * radius_ >= -RVO_EPSILON && det(invTimeHorizonObst * relativePosition2 - orcaLines_[j].point, orcaLines_[j].direction) - invTimeHorizonObst * radius_ >= -RVO_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 = sqr(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;
}
else 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->unitDir_) >= 0.0f) {
line.point = Vector2(0.0f, 0.0f);
line.direction = normalize(Vector2(-relativePosition2.y(), relativePosition2.x()));
orcaLines_.push_back(line);
}
continue;
}
else if (s >= 0.0f && s < 1.0f && distSqLine <= radiusSq) {
/* Collision with obstacle segment. */
line.point = Vector2(0.0f, 0.0f);
line.direction = -obstacle1->unitDir_;
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, rightLegDirection;
if (s < 0.0f && distSqLine <= radiusSq) {
/*
* Obstacle 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) {
/*
* Obstacle 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->unitDir_;
}
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->unitDir_;
}
}
/*
* 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->prevObstacle_;
bool isLeftLegForeign = false;
bool isRightLegForeign = false;
if (obstacle1->isConvex_ && det(leftLegDirection, -leftNeighbor->unitDir_) >= 0.0f) {
/* Left leg points into obstacle. */
leftLegDirection = -leftNeighbor->unitDir_;
isLeftLegForeign = true;
}
if (obstacle2->isConvex_ && det(rightLegDirection, obstacle2->unitDir_) <= 0.0f) {
/* Right leg points into obstacle. */
rightLegDirection = obstacle2->unitDir_;
isRightLegForeign = true;
}
/* Compute cut-off centers. */
const Vector2 leftCutoff = invTimeHorizonObst * (obstacle1->point_ - position_);
const Vector2 rightCutoff = invTimeHorizonObst * (obstacle2->point_ - position_);
const Vector2 cutoffVec = 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) * cutoffVec) / absSq(cutoffVec));
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;
}
else 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 * cutoffVec)));
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->unitDir_;
line.point = leftCutoff + radius_ * invTimeHorizonObst * Vector2(-line.direction.y(), line.direction.x());
orcaLines_.push_back(line);
continue;
}
else 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;
}
else {
/* 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);
continue;
}
}
const size_t numObstLines = orcaLines_.size();
const float invTimeHorizon = 1.0f / timeHorizon_;
/* Create agent ORCA lines. */
for (size_t i = 0; i < agentNeighbors_.size(); ++i) {
const Agent2D *const other = agentNeighbors_[i].second;
//const float timeHorizon_mod = (avoidance_priority_ - other->avoidance_priority_ + 1.0f) * 0.5f;
//const float invTimeHorizon = (1.0f / timeHorizon_) * timeHorizon_mod;
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 = sqr(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 dotProduct1 = w * relativePosition;
if (dotProduct1 < 0.0f && sqr(dotProduct1) > 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;
}
const float dotProduct2 = relativeVelocity * line.direction;
u = dotProduct2 * line.direction - relativeVelocity;
}
}
else {
/* Collision. Project on cut-off circle of time timeStep. */
const float invTimeStep = 1.0f / sim_->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);
}
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));
}
size_t i = agentNeighbors_.size() - 1;
while (i != 0 && distSq < agentNeighbors_[i - 1].first) {
agentNeighbors_[i] = agentNeighbors_[i - 1];
--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->nextObstacle_;
// ignore obstacle if no matching layer/mask
if ((avoidance_mask_ & nextObstacle->avoidance_layers_) == 0) {
return;
}
// ignore obstacle if below or above
if ((elevation_ > obstacle->elevation_ + obstacle->height_) || (elevation_ + height_ < obstacle->elevation_)) {
return;
}
const float distSq = distSqPointLineSegment(obstacle->point_, nextObstacle->point_, position_);
if (distSq < rangeSq) {
obstacleNeighbors_.push_back(std::make_pair(distSq, obstacle));
size_t i = obstacleNeighbors_.size() - 1;
while (i != 0 && distSq < obstacleNeighbors_[i - 1].first) {
obstacleNeighbors_[i] = obstacleNeighbors_[i - 1];
--i;
}
obstacleNeighbors_[i] = std::make_pair(distSq, obstacle);
}
//}
}
void Agent2D::update(RVOSimulator2D *sim_)
{
velocity_ = newVelocity_;
position_ += velocity_ * sim_->timeStep_;
}
bool linearProgram1(const std::vector<Line> &lines, size_t lineNo, float radius, const Vector2 &optVelocity, bool directionOpt, Vector2 &result)
{
const float dotProduct = lines[lineNo].point * lines[lineNo].direction;
const float discriminant = sqr(dotProduct) + sqr(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 (size_t i = 0; 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) <= RVO_EPSILON) {
/* Lines lineNo and i are (almost) parallel. */
if (numerator < 0.0f) {
return false;
}
else {
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;
}
size_t linearProgram2(const std::vector<Line> &lines, float radius, const Vector2 &optVelocity, bool directionOpt, Vector2 &result)
{
if (directionOpt) {
/*
* Optimize direction. Note that the optimization velocity is of unit
* length in this case.
*/
result = optVelocity * radius;
}
else if (absSq(optVelocity) > sqr(radius)) {
/* Optimize closest point and outside circle. */
result = normalize(optVelocity) * radius;
}
else {
/* Optimize closest point and inside circle. */
result = optVelocity;
}
for (size_t i = 0; 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();
}
void linearProgram3(const std::vector<Line> &lines, size_t numObstLines, size_t beginLine, float radius, Vector2 &result)
{
float distance = 0.0f;
for (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<ptrdiff_t>(numObstLines));
for (size_t j = numObstLines; j < i; ++j) {
Line line;
float determinant = det(lines[i].direction, lines[j].direction);
if (std::fabs(determinant) <= RVO_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;
}
else {
/* 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);
}
}
}
}