/*
* Java port of Bullet (c) 2008 Martin Dvorak <jezek2@advel.cz>
*
* Bullet Continuous Collision Detection and Physics Library
* Copyright (c) 2003-2008 Erwin Coumans http://www.bulletphysics.com/
*
* This software is provided 'as-is', without any express or implied warranty.
* In no event will the authors be held liable for any damages arising from
* the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
package com.bulletphysics.collision.narrowphase;
import com.bulletphysics.util.ObjectPool;
import com.bulletphysics.collision.narrowphase.DiscreteCollisionDetectorInterface.ClosestPointInput;
import com.bulletphysics.collision.shapes.ConvexShape;
import com.bulletphysics.linearmath.Transform;
import com.bulletphysics.linearmath.VectorUtil;
import cz.advel.stack.Stack;
import javax.vecmath.Vector3f;
/**
* GjkConvexCast performs a raycast on a convex object using support mapping.
*
* @author jezek2
*/
public class GjkConvexCast extends ConvexCast {
//protected final BulletStack stack = BulletStack.get();
protected final ObjectPool<ClosestPointInput> pointInputsPool = ObjectPool.get(ClosestPointInput.class);
//#ifdef BT_USE_DOUBLE_PRECISION
// private static final int MAX_ITERATIONS = 64;
//#else
private static final int MAX_ITERATIONS = 32;
//#endif
private SimplexSolverInterface simplexSolver;
private ConvexShape convexA;
private ConvexShape convexB;
private GjkPairDetector gjk = new GjkPairDetector();
public GjkConvexCast(ConvexShape convexA, ConvexShape convexB, SimplexSolverInterface simplexSolver) {
this.simplexSolver = simplexSolver;
this.convexA = convexA;
this.convexB = convexB;
}
public boolean calcTimeOfImpact(Transform fromA, Transform toA, Transform fromB, Transform toB, CastResult result) {
simplexSolver.reset();
// compute linear velocity for this interval, to interpolate
// assume no rotation/angular velocity, assert here?
Vector3f linVelA = Stack.alloc(Vector3f.class);
Vector3f linVelB = Stack.alloc(Vector3f.class);
linVelA.sub(toA.origin, fromA.origin);
linVelB.sub(toB.origin, fromB.origin);
float radius = 0.001f;
float lambda = 0f;
Vector3f v = Stack.alloc(Vector3f.class);
v.set(1f, 0f, 0f);
int maxIter = MAX_ITERATIONS;
Vector3f n = Stack.alloc(Vector3f.class);
n.set(0f, 0f, 0f);
boolean hasResult = false;
Vector3f c = Stack.alloc(Vector3f.class);
Vector3f r = Stack.alloc(Vector3f.class);
r.sub(linVelA, linVelB);
float lastLambda = lambda;
//btScalar epsilon = btScalar(0.001);
int numIter = 0;
// first solution, using GJK
Transform identityTrans = Stack.alloc(Transform.class);
identityTrans.setIdentity();
//result.drawCoordSystem(sphereTr);
PointCollector pointCollector = new PointCollector();
gjk.init(convexA, convexB, simplexSolver, null); // penetrationDepthSolver);
ClosestPointInput input = pointInputsPool.get();
input.init();
try {
// we don't use margins during CCD
// gjk.setIgnoreMargin(true);
input.transformA.set(fromA);
input.transformB.set(fromB);
gjk.getClosestPoints(input, pointCollector, null);
hasResult = pointCollector.hasResult;
c.set(pointCollector.pointInWorld);
if (hasResult) {
float dist;
dist = pointCollector.distance;
n.set(pointCollector.normalOnBInWorld);
// not close enough
while (dist > radius) {
numIter++;
if (numIter > maxIter) {
return false; // todo: report a failure
}
float dLambda = 0f;
float projectedLinearVelocity = r.dot(n);
dLambda = dist / (projectedLinearVelocity);
lambda = lambda - dLambda;
if (lambda > 1f) {
return false;
}
if (lambda < 0f) {
return false; // todo: next check with relative epsilon
}
if (lambda <= lastLambda) {
return false;
//n.setValue(0,0,0);
//break;
}
lastLambda = lambda;
// interpolate to next lambda
result.debugDraw(lambda);
VectorUtil.setInterpolate3(input.transformA.origin, fromA.origin, toA.origin, lambda);
VectorUtil.setInterpolate3(input.transformB.origin, fromB.origin, toB.origin, lambda);
gjk.getClosestPoints(input, pointCollector, null);
if (pointCollector.hasResult) {
if (pointCollector.distance < 0f) {
result.fraction = lastLambda;
n.set(pointCollector.normalOnBInWorld);
result.normal.set(n);
result.hitPoint.set(pointCollector.pointInWorld);
return true;
}
c.set(pointCollector.pointInWorld);
n.set(pointCollector.normalOnBInWorld);
dist = pointCollector.distance;
}
else {
// ??
return false;
}
}
// is n normalized?
// don't report time of impact for motion away from the contact normal (or causes minor penetration)
if (n.dot(r) >= -result.allowedPenetration) {
return false;
}
result.fraction = lambda;
result.normal.set(n);
result.hitPoint.set(c);
return true;
}
return false;
}
finally {
pointInputsPool.release(input);
}
}
}