Ejemplo n.º 1
0
        public override void GetClosestPoints(DiscreteCollisionDetectorInterface.ClosestPointInput input, DiscreteCollisionDetectorInterface.Result output, IDebugDraw debugDraw)
        {
            Matrix transformA = input.TransformA;
            Matrix transformB = input.TransformB;

            Vector3 point        = new Vector3();
            Vector3 normal       = new Vector3();
            Single  timeOfImpact = 1.0f;
            Single  depth        = 0.0f;

            //move sphere into triangle space
            Matrix sphereInTr = MathHelper.InverseTimes(transformB, transformA);

            if (Collide(sphereInTr.Translation, point, normal, depth, timeOfImpact))
            {
                output.AddContactPoint(Vector3.TransformNormal(normal, transformB), Vector3.TransformNormal(point, transformB), depth);
            }
        }
Ejemplo n.º 2
0
        public override void GetClosestPoints(DiscreteCollisionDetectorInterface.ClosestPointInput input, DiscreteCollisionDetectorInterface.Result output, IDebugDraw debugDraw)
        {
            float distance = 0;

            Vector3 normalInB = new Vector3();
            Vector3 pointOnA = new Vector3(), pointOnB = new Vector3();

            Matrix localTransA = input.TransformA;
            Matrix localTransB = input.TransformB;

            Vector3 positionOffset = (localTransA.Translation + localTransB.Translation) * 0.5f;

            localTransA.Translation -= positionOffset;
            localTransB.Translation -= positionOffset;

            float marginA = _minkowskiA.Margin;
            float marginB = _minkowskiB.Margin;

            _numGjkChecks++;

            if (_ignoreMargin)
            {
                marginA = 0;
                marginB = 0;
            }

            _currentIteration = 0;

            int gjkMaxIter = 1000;

            _cachedSeparatingAxis = new Vector3(0, 1, 0);

            bool isValid          = false;
            bool checkSimplex     = false;
            bool checkPenetration = true;

            _degenerateSimplex = 0;

            _lastUsedMethod = -1;

            {
                float squaredDistance = MathHelper.Infinity;
                float delta           = 0;

                float margin = marginA + marginB;

                _simplexSolver.Reset();

                while (true)
                {
                    Matrix transABasis = input.TransformA;
                    transABasis.Translation = Vector3.Zero;

                    Matrix transBBasis = input.TransformB;
                    transBBasis.Translation = Vector3.Zero;

                    Vector3 seperatingAxisInA = Vector3.TransformNormal(-_cachedSeparatingAxis, transABasis);
                    Vector3 seperatingAxisInB = Vector3.TransformNormal(_cachedSeparatingAxis, transBBasis);

                    Vector3 pInA   = _minkowskiA.LocalGetSupportingVertexWithoutMargin(seperatingAxisInA);
                    Vector3 qInB   = _minkowskiB.LocalGetSupportingVertexWithoutMargin(seperatingAxisInB);
                    Vector3 pWorld = MathHelper.MatrixToVector(localTransA, pInA);
                    Vector3 qWorld = MathHelper.MatrixToVector(localTransB, qInB);

                    Vector3 w = pWorld - qWorld;
                    delta = Vector3.Dot(_cachedSeparatingAxis, w);

                    if ((delta > 0.0) && (delta * delta > squaredDistance * input.MaximumDistanceSquared))
                    {
                        checkPenetration = false;
                        break;
                    }

                    if (_simplexSolver.InSimplex(w))
                    {
                        _degenerateSimplex = 1;
                        checkSimplex       = true;
                        break;
                    }

                    float f0 = squaredDistance - delta;
                    float f1 = squaredDistance * RelativeError2;

                    if (f0 <= f1)
                    {
                        if (f0 <= 0.0f)
                        {
                            _degenerateSimplex = 2;
                        }

                        checkSimplex = true;
                        break;
                    }

                    _simplexSolver.AddVertex(w, pWorld, qWorld);

                    if (!_simplexSolver.Closest(out _cachedSeparatingAxis))
                    {
                        _degenerateSimplex = 3;
                        checkSimplex       = true;
                        break;
                    }

                    float previouseSquaredDistance = squaredDistance;
                    squaredDistance = _cachedSeparatingAxis.LengthSquared();

                    if (previouseSquaredDistance - squaredDistance <= MathHelper.Epsilon * previouseSquaredDistance)
                    {
                        _simplexSolver.BackupClosest(out _cachedSeparatingAxis);
                        checkSimplex = true;
                        break;
                    }

                    if (_currentIteration++ > gjkMaxIter)
                    {
#if DEBUG
                        Console.WriteLine("GjkPairDetector maxIter exceeded: {0}", _currentIteration);
                        Console.WriteLine("sepAxis=({0},{1},{2}), squaredDistance = {3}, shapeTypeA={4}, shapeTypeB={5}",
                                          _cachedSeparatingAxis.X,
                                          _cachedSeparatingAxis.Y,
                                          _cachedSeparatingAxis.Z,
                                          squaredDistance,
                                          _minkowskiA.ShapeType,
                                          _minkowskiB.ShapeType
                                          );
#endif
                        break;
                    }

                    bool check = (!_simplexSolver.FullSimplex);

                    if (!check)
                    {
                        _simplexSolver.BackupClosest(out _cachedSeparatingAxis);
                        break;
                    }
                }

                if (checkSimplex)
                {
                    _simplexSolver.ComputePoints(out pointOnA, out pointOnB);
                    normalInB = pointOnA - pointOnB;
                    float lenSqr = _cachedSeparatingAxis.LengthSquared();

                    if (lenSqr < 0.0001f)
                    {
                        _degenerateSimplex = 5;
                    }

                    if (lenSqr > MathHelper.Epsilon * MathHelper.Epsilon)
                    {
                        float rlen = 1.0f / (float)Math.Sqrt((float)lenSqr);
                        normalInB *= rlen;
                        float s = (float)Math.Sqrt((float)squaredDistance);

                        BulletDebug.Assert(s > 0);
                        pointOnA -= _cachedSeparatingAxis * (marginA / s);
                        pointOnB += _cachedSeparatingAxis * (marginB / s);
                        distance  = ((1 / rlen) - margin);

                        isValid = true;

                        _lastUsedMethod = 1;
                    }
                    else
                    {
                        _lastUsedMethod = 2;
                    }
                }

                bool catchDegeneratePenetrationCase =
                    (_catchDegeneracies != 0 && _penetrationDepthSolver != null && _degenerateSimplex != 0 && ((distance + margin) < 0.01f));

                if (checkPenetration && (!isValid || catchDegeneratePenetrationCase))
                {
#warning Check this
                    if (_penetrationDepthSolver != null)
                    {
                        Vector3 tmpPointOnA, tmpPointOnB;

                        _numDeepPenetrationChecks++;

                        bool isValid2 = _penetrationDepthSolver.CalculatePenetrationDepth(
                            _simplexSolver, _minkowskiA, _minkowskiB, localTransA, localTransB,
                            _cachedSeparatingAxis, out tmpPointOnA, out tmpPointOnB,
                            debugDraw
                            );

                        if (isValid2)
                        {
                            Vector3 tmpNormalInB = tmpPointOnB - tmpPointOnA;
                            float   lengSqr      = tmpNormalInB.LengthSquared();

                            if (lengSqr > (MathHelper.Epsilon * MathHelper.Epsilon))
                            {
                                tmpNormalInB /= (float)Math.Sqrt((float)lengSqr);
                                float distance2 = -(tmpPointOnA - tmpPointOnB).Length();

                                if (!isValid || (distance2 < distance))
                                {
                                    distance        = distance2;
                                    pointOnA        = tmpPointOnA;
                                    pointOnB        = tmpPointOnB;
                                    normalInB       = tmpNormalInB;
                                    isValid         = true;
                                    _lastUsedMethod = 3;
                                }
                                else
                                {
                                }
                            }
                            else
                            {
                                _lastUsedMethod = 4;
                            }
                        }
                        else
                        {
                            _lastUsedMethod = 5;
                        }
                    }
                }

                if (isValid)
                {
                    output.AddContactPoint(normalInB, pointOnB + positionOffset, distance);
                }
            }
        }
        public bool CalcTimeOfImpact(Matrix fromA, Matrix toA, Matrix fromB, Matrix toB, CastResult result)
        {
            _simplexSolver.Reset();

            // compute linear and angular velocity for this interval, to interpolate
            Vector3 linVelA = new Vector3(), angVelA = new Vector3(), linVelB = new Vector3(), angVelB = new Vector3();

            TransformUtil.CalculateVelocity(fromA, toA, 1f, ref linVelA, ref angVelA);
            TransformUtil.CalculateVelocity(fromB, toB, 1f, ref linVelB, ref angVelB);

            float boundingRadiusA = _convexA.GetAngularMotionDisc();
            float boundingRadiusB = _convexB.GetAngularMotionDisc();

            float maxAngularProjectedVelocity = angVelA.Length() * boundingRadiusA +
                                                angVelB.Length() * boundingRadiusB;

            float radius = 0.001f;

            float   lambda = 0f;
            Vector3 v      = new Vector3(1f, 0f, 0f);

            int maxIter = MaxIterations;

            Vector3 n         = new Vector3();
            bool    hasResult = false;
            Vector3 c;

            float lastLambda = lambda;
            //float epsilon = 0.001f;

            int numIter = 0;
            //first solution, using GJK


            Matrix identityTrans = Matrix.Identity;

            SphereShape raySphere = new SphereShape(0f);

            raySphere.Margin = 0f;


            //result.drawCoordSystem(sphereTr);

            PointCollector pointCollector1 = new PointCollector();

            GjkPairDetector gjk = new GjkPairDetector(_convexA, _convexB, (VoronoiSimplexSolver)_simplexSolver, _penetrationDepthSolver);

            GjkPairDetector.ClosestPointInput input = new DiscreteCollisionDetectorInterface.ClosestPointInput();

            //we don't use margins during CCD
            gjk.setIgnoreMargin(true);

            input.TransformA = fromA;
            input.TransformB = fromB;

            DiscreteCollisionDetectorInterface.Result r = (DiscreteCollisionDetectorInterface.Result)pointCollector1;
            gjk.GetClosestPoints(input, r, null);

            hasResult = pointCollector1.HasResult;
            c         = pointCollector1.PointInWorld;

            if (hasResult)
            {
                float dist;
                dist = pointCollector1.Distance;
                n    = pointCollector1.NormalOnBInWorld;

                //not close enough
                while (dist > radius)
                {
                    numIter++;
                    if (numIter > maxIter)
                    {
                        return(false);                        //todo: report a failure
                    }
                    float dLambda = 0f;

                    //calculate safe moving fraction from distance / (linear+rotational velocity)

                    //float clippedDist  = GEN_min(angularConservativeRadius,dist);
                    //float clippedDist  = dist;

                    float projectedLinearVelocity = Vector3.Dot(linVelB - linVelA, n);

                    dLambda = dist / (projectedLinearVelocity + maxAngularProjectedVelocity);

                    lambda = lambda + dLambda;

                    if (lambda > 1f)
                    {
                        return(false);
                    }
                    if (lambda < 0f)
                    {
                        return(false);
                    }

                    //todo: next check with relative epsilon
                    if (lambda <= lastLambda)
                    {
                        break;
                    }
                    lastLambda = lambda;


                    //interpolate to next lambda
                    Matrix interpolatedTransA = new Matrix(), interpolatedTransB = new Matrix(), relativeTrans;

                    TransformUtil.IntegrateTransform(fromA, linVelA, angVelA, lambda, ref interpolatedTransA);
                    TransformUtil.IntegrateTransform(fromB, linVelB, angVelB, lambda, ref interpolatedTransB);

                    relativeTrans = MathHelper.InverseTimes(interpolatedTransB, interpolatedTransA);

                    result.DebugDraw(lambda);

                    PointCollector pointCollector = new PointCollector();
                    gjk              = new GjkPairDetector(_convexA, _convexB, (VoronoiSimplexSolver)_simplexSolver, _penetrationDepthSolver);
                    input            = new DiscreteCollisionDetectorInterface.ClosestPointInput();
                    input.TransformA = interpolatedTransA;
                    input.TransformB = interpolatedTransB;

                    // !!!!!!!!!!
                    r = (DiscreteCollisionDetectorInterface.Result)pointCollector1;
                    gjk.GetClosestPoints(input, r, null);

                    if (pointCollector.HasResult)
                    {
                        if (pointCollector.Distance < 0f)
                        {
                            //degenerate ?!
                            result.Fraction = lastLambda;
                            result.Normal   = n;
                            return(true);
                        }
                        c = pointCollector.PointInWorld;

                        dist = pointCollector.Distance;
                    }
                    else
                    {
                        //??
                        return(false);
                    }
                }

                result.Fraction = lambda;
                result.Normal   = n;
                return(true);
            }

            return(false);
        }