public void WarmStart()
{
for (int i = 0; i < this._count; i++)
{
ContactVelocityConstraint contactVelocityConstraint = this._velocityConstraints[i];
int indexA = contactVelocityConstraint.indexA;
int indexB = contactVelocityConstraint.indexB;
FP invMassA = contactVelocityConstraint.invMassA;
FP invIA = contactVelocityConstraint.invIA;
FP invMassB = contactVelocityConstraint.invMassB;
FP invIB = contactVelocityConstraint.invIB;
int pointCount = contactVelocityConstraint.pointCount;
TSVector2 tSVector = this._velocities[indexA].v;
FP fP = this._velocities[indexA].w;
TSVector2 tSVector2 = this._velocities[indexB].v;
FP fP2 = this._velocities[indexB].w;
TSVector2 normal = contactVelocityConstraint.normal;
TSVector2 value = MathUtils.Cross(normal, 1f);
for (int j = 0; j < pointCount; j++)
{
VelocityConstraintPoint velocityConstraintPoint = contactVelocityConstraint.points[j];
TSVector2 tSVector3 = velocityConstraintPoint.normalImpulse * normal + velocityConstraintPoint.tangentImpulse * value;
fP -= invIA * MathUtils.Cross(velocityConstraintPoint.rA, tSVector3);
tSVector -= invMassA * tSVector3;
fP2 += invIB * MathUtils.Cross(velocityConstraintPoint.rB, tSVector3);
tSVector2 += invMassB * tSVector3;
}
this._velocities[indexA].v = tSVector;
this._velocities[indexA].w = fP;
this._velocities[indexB].v = tSVector2;
this._velocities[indexB].w = fP2;
}
}
public void StoreImpulses()
{
for (int i = 0; i < this._count; i++)
{
ContactVelocityConstraint contactVelocityConstraint = this._velocityConstraints[i];
Manifold manifold = this._contacts[contactVelocityConstraint.contactIndex].Manifold;
for (int j = 0; j < contactVelocityConstraint.pointCount; j++)
{
ManifoldPoint value = manifold.Points[j];
value.NormalImpulse = contactVelocityConstraint.points[j].normalImpulse;
value.TangentImpulse = contactVelocityConstraint.points[j].tangentImpulse;
manifold.Points[j] = value;
}
this._contacts[contactVelocityConstraint.contactIndex].Manifold = manifold;
}
}
public void StoreImpulses()
{
for (int i = 0; i < _count; ++i)
{
ContactVelocityConstraint vc = _velocityConstraints[i];
Manifold manifold = _contacts[vc.contactIndex].Manifold;
for (int j = 0; j < vc.pointCount; ++j)
{
ManifoldPoint point = manifold.Points[j];
point.NormalImpulse = vc.points[j].normalImpulse;
point.TangentImpulse = vc.points[j].tangentImpulse;
manifold.Points[j] = point;
}
_contacts[vc.contactIndex].Manifold = manifold;
}
}
public void WarmStart()
{
// Warm start.
for (int i = 0; i < _count; ++i)
{
ContactVelocityConstraint vc = _velocityConstraints[i];
int indexA = vc.indexA;
int indexB = vc.indexB;
FP mA = vc.invMassA;
FP iA = vc.invIA;
FP mB = vc.invMassB;
FP iB = vc.invIB;
int pointCount = vc.pointCount;
TSVector2 vA = _velocities[indexA].v;
FP wA = _velocities[indexA].w;
TSVector2 vB = _velocities[indexB].v;
FP wB = _velocities[indexB].w;
TSVector2 normal = vc.normal;
TSVector2 tangent = MathUtils.Cross(normal, 1.0f);
for (int j = 0; j < pointCount; ++j)
{
VelocityConstraintPoint vcp = vc.points[j];
TSVector2 P = vcp.normalImpulse * normal + vcp.tangentImpulse * tangent;
wA -= iA * MathUtils.Cross(vcp.rA, P);
vA -= mA * P;
wB += iB * MathUtils.Cross(vcp.rB, P);
vB += mB * P;
}
_velocities[indexA].v = vA;
_velocities[indexA].w = wA;
_velocities[indexB].v = vB;
_velocities[indexB].w = wB;
}
}
private void PostSolve(Contact contact, ContactVelocityConstraint impulse)
{
if (!Broken)
{
if (Parts.Contains(contact.FixtureA) || Parts.Contains(contact.FixtureB))
{
FP maxImpulse = 0.0f;
int count = contact.Manifold.PointCount;
for (int i = 0; i < count; ++i)
{
maxImpulse = TrueSync.TSMath.Max(maxImpulse, impulse.points[i].normalImpulse);
}
if (maxImpulse > Strength)
{
// Flag the body for breaking.
_break = true;
}
}
}
}
private void PostSolve(Contact contact, ContactVelocityConstraint impulse)
{
bool flag = !this.Broken;
if (flag)
{
bool flag2 = this.Parts.Contains(contact.FixtureA) || this.Parts.Contains(contact.FixtureB);
if (flag2)
{
FP fP = 0f;
int pointCount = contact.Manifold.PointCount;
for (int i = 0; i < pointCount; i++)
{
fP = TSMath.Max(fP, impulse.points[i].normalImpulse);
}
bool flag3 = fP > this.Strength;
if (flag3)
{
this._break = true;
}
}
}
}
public void SolveVelocityConstraints()
{
for (int i = 0; i < this._count; i++)
{
ContactVelocityConstraint contactVelocityConstraint = this._velocityConstraints[i];
int indexA = contactVelocityConstraint.indexA;
int indexB = contactVelocityConstraint.indexB;
FP invMassA = contactVelocityConstraint.invMassA;
FP invIA = contactVelocityConstraint.invIA;
FP invMassB = contactVelocityConstraint.invMassB;
FP invIB = contactVelocityConstraint.invIB;
int pointCount = contactVelocityConstraint.pointCount;
TSVector2 tSVector = this._velocities[indexA].v;
FP fP = this._velocities[indexA].w;
TSVector2 tSVector2 = this._velocities[indexB].v;
FP fP2 = this._velocities[indexB].w;
TSVector2 normal = contactVelocityConstraint.normal;
TSVector2 tSVector3 = MathUtils.Cross(normal, 1f);
FP friction = contactVelocityConstraint.friction;
Debug.Assert(pointCount == 1 || pointCount == 2);
for (int j = 0; j < pointCount; j++)
{
VelocityConstraintPoint velocityConstraintPoint = contactVelocityConstraint.points[j];
TSVector2 value = tSVector2 + MathUtils.Cross(fP2, velocityConstraintPoint.rB) - tSVector - MathUtils.Cross(fP, velocityConstraintPoint.rA);
FP x = TSVector2.Dot(value, tSVector3) - contactVelocityConstraint.tangentSpeed;
FP fP3 = velocityConstraintPoint.tangentMass * -x;
FP fP4 = friction * velocityConstraintPoint.normalImpulse;
FP fP5 = MathUtils.Clamp(velocityConstraintPoint.tangentImpulse + fP3, -fP4, fP4);
fP3 = fP5 - velocityConstraintPoint.tangentImpulse;
velocityConstraintPoint.tangentImpulse = fP5;
TSVector2 tSVector4 = fP3 * tSVector3;
tSVector -= invMassA * tSVector4;
fP -= invIA * MathUtils.Cross(velocityConstraintPoint.rA, tSVector4);
tSVector2 += invMassB * tSVector4;
fP2 += invIB * MathUtils.Cross(velocityConstraintPoint.rB, tSVector4);
}
bool flag = contactVelocityConstraint.pointCount == 1;
if (flag)
{
VelocityConstraintPoint velocityConstraintPoint2 = contactVelocityConstraint.points[0];
TSVector2 value2 = tSVector2 + MathUtils.Cross(fP2, velocityConstraintPoint2.rB) - tSVector - MathUtils.Cross(fP, velocityConstraintPoint2.rA);
FP x2 = TSVector2.Dot(value2, normal);
FP fP6 = -velocityConstraintPoint2.normalMass * (x2 - velocityConstraintPoint2.velocityBias);
FP fP7 = TSMath.Max(velocityConstraintPoint2.normalImpulse + fP6, 0f);
fP6 = fP7 - velocityConstraintPoint2.normalImpulse;
velocityConstraintPoint2.normalImpulse = fP7;
TSVector2 tSVector5 = fP6 * normal;
tSVector -= invMassA * tSVector5;
fP -= invIA * MathUtils.Cross(velocityConstraintPoint2.rA, tSVector5);
tSVector2 += invMassB * tSVector5;
fP2 += invIB * MathUtils.Cross(velocityConstraintPoint2.rB, tSVector5);
}
else
{
VelocityConstraintPoint velocityConstraintPoint3 = contactVelocityConstraint.points[0];
VelocityConstraintPoint velocityConstraintPoint4 = contactVelocityConstraint.points[1];
TSVector2 tSVector6 = new TSVector2(velocityConstraintPoint3.normalImpulse, velocityConstraintPoint4.normalImpulse);
Debug.Assert(tSVector6.x >= 0f && tSVector6.y >= 0f);
TSVector2 value3 = tSVector2 + MathUtils.Cross(fP2, velocityConstraintPoint3.rB) - tSVector - MathUtils.Cross(fP, velocityConstraintPoint3.rA);
TSVector2 value4 = tSVector2 + MathUtils.Cross(fP2, velocityConstraintPoint4.rB) - tSVector - MathUtils.Cross(fP, velocityConstraintPoint4.rA);
FP x3 = TSVector2.Dot(value3, normal);
FP x4 = TSVector2.Dot(value4, normal);
TSVector2 tSVector7 = new TSVector2
{
x = x3 - velocityConstraintPoint3.velocityBias,
y = x4 - velocityConstraintPoint4.velocityBias
} -MathUtils.Mul(ref contactVelocityConstraint.K, tSVector6);
TSVector2 tSVector8 = -MathUtils.Mul(ref contactVelocityConstraint.normalMass, tSVector7);
bool flag2 = tSVector8.x >= 0f && tSVector8.y >= 0f;
if (flag2)
{
TSVector2 tSVector9 = tSVector8 - tSVector6;
TSVector2 tSVector10 = tSVector9.x * normal;
TSVector2 tSVector11 = tSVector9.y * normal;
tSVector -= invMassA * (tSVector10 + tSVector11);
fP -= invIA * (MathUtils.Cross(velocityConstraintPoint3.rA, tSVector10) + MathUtils.Cross(velocityConstraintPoint4.rA, tSVector11));
tSVector2 += invMassB * (tSVector10 + tSVector11);
fP2 += invIB * (MathUtils.Cross(velocityConstraintPoint3.rB, tSVector10) + MathUtils.Cross(velocityConstraintPoint4.rB, tSVector11));
velocityConstraintPoint3.normalImpulse = tSVector8.x;
velocityConstraintPoint4.normalImpulse = tSVector8.y;
}
else
{
tSVector8.x = -velocityConstraintPoint3.normalMass * tSVector7.x;
tSVector8.y = 0f;
x3 = 0f;
x4 = contactVelocityConstraint.K.ex.y * tSVector8.x + tSVector7.y;
bool flag3 = tSVector8.x >= 0f && x4 >= 0f;
if (flag3)
{
TSVector2 tSVector12 = tSVector8 - tSVector6;
TSVector2 tSVector13 = tSVector12.x * normal;
TSVector2 tSVector14 = tSVector12.y * normal;
tSVector -= invMassA * (tSVector13 + tSVector14);
fP -= invIA * (MathUtils.Cross(velocityConstraintPoint3.rA, tSVector13) + MathUtils.Cross(velocityConstraintPoint4.rA, tSVector14));
tSVector2 += invMassB * (tSVector13 + tSVector14);
fP2 += invIB * (MathUtils.Cross(velocityConstraintPoint3.rB, tSVector13) + MathUtils.Cross(velocityConstraintPoint4.rB, tSVector14));
velocityConstraintPoint3.normalImpulse = tSVector8.x;
velocityConstraintPoint4.normalImpulse = tSVector8.y;
}
else
{
tSVector8.x = 0f;
tSVector8.y = -velocityConstraintPoint4.normalMass * tSVector7.y;
x3 = contactVelocityConstraint.K.ey.x * tSVector8.y + tSVector7.x;
x4 = 0f;
bool flag4 = tSVector8.y >= 0f && x3 >= 0f;
if (flag4)
{
TSVector2 tSVector15 = tSVector8 - tSVector6;
TSVector2 tSVector16 = tSVector15.x * normal;
TSVector2 tSVector17 = tSVector15.y * normal;
tSVector -= invMassA * (tSVector16 + tSVector17);
fP -= invIA * (MathUtils.Cross(velocityConstraintPoint3.rA, tSVector16) + MathUtils.Cross(velocityConstraintPoint4.rA, tSVector17));
tSVector2 += invMassB * (tSVector16 + tSVector17);
fP2 += invIB * (MathUtils.Cross(velocityConstraintPoint3.rB, tSVector16) + MathUtils.Cross(velocityConstraintPoint4.rB, tSVector17));
velocityConstraintPoint3.normalImpulse = tSVector8.x;
velocityConstraintPoint4.normalImpulse = tSVector8.y;
}
else
{
tSVector8.x = 0f;
tSVector8.y = 0f;
x3 = tSVector7.x;
x4 = tSVector7.y;
bool flag5 = x3 >= 0f && x4 >= 0f;
if (flag5)
{
TSVector2 tSVector18 = tSVector8 - tSVector6;
TSVector2 tSVector19 = tSVector18.x * normal;
TSVector2 tSVector20 = tSVector18.y * normal;
tSVector -= invMassA * (tSVector19 + tSVector20);
fP -= invIA * (MathUtils.Cross(velocityConstraintPoint3.rA, tSVector19) + MathUtils.Cross(velocityConstraintPoint4.rA, tSVector20));
tSVector2 += invMassB * (tSVector19 + tSVector20);
fP2 += invIB * (MathUtils.Cross(velocityConstraintPoint3.rB, tSVector19) + MathUtils.Cross(velocityConstraintPoint4.rB, tSVector20));
velocityConstraintPoint3.normalImpulse = tSVector8.x;
velocityConstraintPoint4.normalImpulse = tSVector8.y;
}
}
}
}
}
this._velocities[indexA].v = tSVector;
this._velocities[indexA].w = fP;
this._velocities[indexB].v = tSVector2;
this._velocities[indexB].w = fP2;
}
}
public void InitializeVelocityConstraints()
{
for (int i = 0; i < this._count; i++)
{
ContactVelocityConstraint contactVelocityConstraint = this._velocityConstraints[i];
ContactPositionConstraint contactPositionConstraint = this._positionConstraints[i];
FP radiusA = contactPositionConstraint.radiusA;
FP radiusB = contactPositionConstraint.radiusB;
Manifold manifold = this._contacts[contactVelocityConstraint.contactIndex].Manifold;
int indexA = contactVelocityConstraint.indexA;
int indexB = contactVelocityConstraint.indexB;
FP invMassA = contactVelocityConstraint.invMassA;
FP invMassB = contactVelocityConstraint.invMassB;
FP invIA = contactVelocityConstraint.invIA;
FP invIB = contactVelocityConstraint.invIB;
TSVector2 localCenterA = contactPositionConstraint.localCenterA;
TSVector2 localCenterB = contactPositionConstraint.localCenterB;
TSVector2 c = this._positions[indexA].c;
FP a = this._positions[indexA].a;
TSVector2 v = this._velocities[indexA].v;
FP w = this._velocities[indexA].w;
TSVector2 c2 = this._positions[indexB].c;
FP a2 = this._positions[indexB].a;
TSVector2 v2 = this._velocities[indexB].v;
FP w2 = this._velocities[indexB].w;
Debug.Assert(manifold.PointCount > 0);
Transform transform = default(Transform);
Transform transform2 = default(Transform);
transform.q.Set(a);
transform2.q.Set(a2);
transform.p = c - MathUtils.Mul(transform.q, localCenterA);
transform2.p = c2 - MathUtils.Mul(transform2.q, localCenterB);
TSVector2 normal;
FixedArray2 <TSVector2> fixedArray;
ContactSolver.WorldManifold.Initialize(ref manifold, ref transform, radiusA, ref transform2, radiusB, out normal, out fixedArray);
contactVelocityConstraint.normal = normal;
int pointCount = contactVelocityConstraint.pointCount;
for (int j = 0; j < pointCount; j++)
{
VelocityConstraintPoint velocityConstraintPoint = contactVelocityConstraint.points[j];
velocityConstraintPoint.rA = fixedArray[j] - c;
velocityConstraintPoint.rB = fixedArray[j] - c2;
FP y = MathUtils.Cross(velocityConstraintPoint.rA, contactVelocityConstraint.normal);
FP y2 = MathUtils.Cross(velocityConstraintPoint.rB, contactVelocityConstraint.normal);
FP fP = invMassA + invMassB + invIA * y * y + invIB * y2 * y2;
velocityConstraintPoint.normalMass = ((fP > 0f) ? (1f / fP) : 0f);
TSVector2 b = MathUtils.Cross(contactVelocityConstraint.normal, 1f);
FP y3 = MathUtils.Cross(velocityConstraintPoint.rA, b);
FP y4 = MathUtils.Cross(velocityConstraintPoint.rB, b);
FP fP2 = invMassA + invMassB + invIA * y3 * y3 + invIB * y4 * y4;
velocityConstraintPoint.tangentMass = ((fP2 > 0f) ? (1f / fP2) : 0f);
velocityConstraintPoint.velocityBias = 0f;
FP fP3 = TSVector2.Dot(contactVelocityConstraint.normal, v2 + MathUtils.Cross(w2, velocityConstraintPoint.rB) - v - MathUtils.Cross(w, velocityConstraintPoint.rA));
bool flag = fP3 < -Settings.VelocityThreshold;
if (flag)
{
velocityConstraintPoint.velocityBias = -contactVelocityConstraint.restitution * fP3;
}
}
bool flag2 = contactVelocityConstraint.pointCount == 2;
if (flag2)
{
VelocityConstraintPoint velocityConstraintPoint2 = contactVelocityConstraint.points[0];
VelocityConstraintPoint velocityConstraintPoint3 = contactVelocityConstraint.points[1];
FP y5 = MathUtils.Cross(velocityConstraintPoint2.rA, contactVelocityConstraint.normal);
FP y6 = MathUtils.Cross(velocityConstraintPoint2.rB, contactVelocityConstraint.normal);
FP y7 = MathUtils.Cross(velocityConstraintPoint3.rA, contactVelocityConstraint.normal);
FP y8 = MathUtils.Cross(velocityConstraintPoint3.rB, contactVelocityConstraint.normal);
FP fP4 = invMassA + invMassB + invIA * y5 * y5 + invIB * y6 * y6;
FP y9 = invMassA + invMassB + invIA * y7 * y7 + invIB * y8 * y8;
FP fP5 = invMassA + invMassB + invIA * y5 * y7 + invIB * y6 * y8;
FP x = 1000f;
bool flag3 = fP4 * fP4 < x * (fP4 * y9 - fP5 * fP5);
if (flag3)
{
contactVelocityConstraint.K.ex = new TSVector2(fP4, fP5);
contactVelocityConstraint.K.ey = new TSVector2(fP5, y9);
contactVelocityConstraint.normalMass = contactVelocityConstraint.K.Inverse;
}
else
{
contactVelocityConstraint.pointCount = 1;
}
}
}
}
public void Reset(TimeStep step, int count, Contact[] contacts, Position[] positions, Velocity[] velocities, bool warmstarting = true)
{
this._step = step;
this._count = count;
this._positions = positions;
this._velocities = velocities;
this._contacts = contacts;
bool flag = this._velocityConstraints == null || this._velocityConstraints.Length < count;
if (flag)
{
this._velocityConstraints = new ContactVelocityConstraint[count * 2];
this._positionConstraints = new ContactPositionConstraint[count * 2];
for (int i = 0; i < this._velocityConstraints.Length; i++)
{
this._velocityConstraints[i] = new ContactVelocityConstraint();
}
for (int j = 0; j < this._positionConstraints.Length; j++)
{
this._positionConstraints[j] = new ContactPositionConstraint();
}
}
for (int k = 0; k < this._count; k++)
{
Contact contact = contacts[k];
Fixture fixtureA = contact.FixtureA;
Fixture fixtureB = contact.FixtureB;
Shape shape = fixtureA.Shape;
Shape shape2 = fixtureB.Shape;
FP radius = shape.Radius;
FP radius2 = shape2.Radius;
Body body = fixtureA.Body;
Body body2 = fixtureB.Body;
Manifold manifold = contact.Manifold;
int pointCount = manifold.PointCount;
Debug.Assert(pointCount > 0);
ContactVelocityConstraint contactVelocityConstraint = this._velocityConstraints[k];
contactVelocityConstraint.friction = contact.Friction;
contactVelocityConstraint.restitution = contact.Restitution;
contactVelocityConstraint.tangentSpeed = contact.TangentSpeed;
contactVelocityConstraint.indexA = body.IslandIndex;
contactVelocityConstraint.indexB = body2.IslandIndex;
contactVelocityConstraint.invMassA = body._invMass;
contactVelocityConstraint.invMassB = body2._invMass;
contactVelocityConstraint.invIA = body._invI;
contactVelocityConstraint.invIB = body2._invI;
contactVelocityConstraint.contactIndex = k;
contactVelocityConstraint.pointCount = pointCount;
contactVelocityConstraint.K.SetZero();
contactVelocityConstraint.normalMass.SetZero();
ContactPositionConstraint contactPositionConstraint = this._positionConstraints[k];
contactPositionConstraint.indexA = body.IslandIndex;
contactPositionConstraint.indexB = body2.IslandIndex;
contactPositionConstraint.invMassA = body._invMass;
contactPositionConstraint.invMassB = body2._invMass;
contactPositionConstraint.localCenterA = body._sweep.LocalCenter;
contactPositionConstraint.localCenterB = body2._sweep.LocalCenter;
contactPositionConstraint.invIA = body._invI;
contactPositionConstraint.invIB = body2._invI;
contactPositionConstraint.localNormal = manifold.LocalNormal;
contactPositionConstraint.localPoint = manifold.LocalPoint;
contactPositionConstraint.pointCount = pointCount;
contactPositionConstraint.radiusA = radius;
contactPositionConstraint.radiusB = radius2;
contactPositionConstraint.type = manifold.Type;
for (int l = 0; l < pointCount; l++)
{
ManifoldPoint manifoldPoint = manifold.Points[l];
VelocityConstraintPoint velocityConstraintPoint = contactVelocityConstraint.points[l];
velocityConstraintPoint.normalImpulse = this._step.dtRatio * manifoldPoint.NormalImpulse;
velocityConstraintPoint.tangentImpulse = this._step.dtRatio * manifoldPoint.TangentImpulse;
velocityConstraintPoint.rA = TSVector2.zero;
velocityConstraintPoint.rB = TSVector2.zero;
velocityConstraintPoint.normalMass = 0f;
velocityConstraintPoint.tangentMass = 0f;
velocityConstraintPoint.velocityBias = 0f;
contactPositionConstraint.localPoints[l] = manifoldPoint.LocalPoint;
}
}
}
public void Reset(TimeStep step, int count, Contact[] contacts, Position[] positions, Velocity[] velocities, bool warmstarting = Settings.EnableWarmstarting)
{
_step = step;
_count = count;
_positions = positions;
_velocities = velocities;
_contacts = contacts;
// grow the array
if (_velocityConstraints == null || _velocityConstraints.Length < count)
{
_velocityConstraints = new ContactVelocityConstraint[count * 2];
_positionConstraints = new ContactPositionConstraint[count * 2];
for (int i = 0; i < _velocityConstraints.Length; i++)
{
_velocityConstraints[i] = new ContactVelocityConstraint();
}
for (int i = 0; i < _positionConstraints.Length; i++)
{
_positionConstraints[i] = new ContactPositionConstraint();
}
}
// Initialize position independent portions of the constraints.
for (int i = 0; i < _count; ++i)
{
Contact contact = contacts[i];
Fixture fixtureA = contact.FixtureA;
Fixture fixtureB = contact.FixtureB;
Shape shapeA = fixtureA.Shape;
Shape shapeB = fixtureB.Shape;
FP radiusA = shapeA.Radius;
FP radiusB = shapeB.Radius;
Body bodyA = fixtureA.Body;
Body bodyB = fixtureB.Body;
Manifold manifold = contact.Manifold;
int pointCount = manifold.PointCount;
Debug.Assert(pointCount > 0);
ContactVelocityConstraint vc = _velocityConstraints[i];
vc.friction = contact.Friction;
vc.restitution = contact.Restitution;
vc.tangentSpeed = contact.TangentSpeed;
vc.indexA = bodyA.IslandIndex;
vc.indexB = bodyB.IslandIndex;
vc.invMassA = bodyA._invMass;
vc.invMassB = bodyB._invMass;
vc.invIA = bodyA._invI;
vc.invIB = bodyB._invI;
vc.contactIndex = i;
vc.pointCount = pointCount;
vc.K.SetZero();
vc.normalMass.SetZero();
ContactPositionConstraint pc = _positionConstraints[i];
pc.indexA = bodyA.IslandIndex;
pc.indexB = bodyB.IslandIndex;
pc.invMassA = bodyA._invMass;
pc.invMassB = bodyB._invMass;
pc.localCenterA = bodyA._sweep.LocalCenter;
pc.localCenterB = bodyB._sweep.LocalCenter;
pc.invIA = bodyA._invI;
pc.invIB = bodyB._invI;
pc.localNormal = manifold.LocalNormal;
pc.localPoint = manifold.LocalPoint;
pc.pointCount = pointCount;
pc.radiusA = radiusA;
pc.radiusB = radiusB;
pc.type = manifold.Type;
for (int j = 0; j < pointCount; ++j)
{
ManifoldPoint cp = manifold.Points[j];
VelocityConstraintPoint vcp = vc.points[j];
if (Settings.EnableWarmstarting)
{
vcp.normalImpulse = _step.dtRatio * cp.NormalImpulse;
vcp.tangentImpulse = _step.dtRatio * cp.TangentImpulse;
}
else
{
vcp.normalImpulse = 0.0f;
vcp.tangentImpulse = 0.0f;
}
vcp.rA = TSVector2.zero;
vcp.rB = TSVector2.zero;
vcp.normalMass = 0.0f;
vcp.tangentMass = 0.0f;
vcp.velocityBias = 0.0f;
pc.localPoints[j] = cp.LocalPoint;
}
}
}
public void SolveVelocityConstraints()
{
for (int i = 0; i < _count; ++i)
{
ContactVelocityConstraint vc = _velocityConstraints[i];
int indexA = vc.indexA;
int indexB = vc.indexB;
FP mA = vc.invMassA;
FP iA = vc.invIA;
FP mB = vc.invMassB;
FP iB = vc.invIB;
int pointCount = vc.pointCount;
TSVector2 vA = _velocities[indexA].v;
FP wA = _velocities[indexA].w;
TSVector2 vB = _velocities[indexB].v;
FP wB = _velocities[indexB].w;
TSVector2 normal = vc.normal;
TSVector2 tangent = MathUtils.Cross(normal, 1.0f);
FP friction = vc.friction;
Debug.Assert(pointCount == 1 || pointCount == 2);
// Solve tangent constraints first because non-penetration is more important
// than friction.
for (int j = 0; j < pointCount; ++j)
{
VelocityConstraintPoint vcp = vc.points[j];
// Relative velocity at contact
TSVector2 dv = vB + MathUtils.Cross(wB, vcp.rB) - vA - MathUtils.Cross(wA, vcp.rA);
// Compute tangent force
FP vt = TSVector2.Dot(dv, tangent) - vc.tangentSpeed;
FP lambda = vcp.tangentMass * (-vt);
// b2Clamp the accumulated force
FP maxFriction = friction * vcp.normalImpulse;
FP newImpulse = MathUtils.Clamp(vcp.tangentImpulse + lambda, -maxFriction, maxFriction);
lambda = newImpulse - vcp.tangentImpulse;
vcp.tangentImpulse = newImpulse;
// Apply contact impulse
TSVector2 P = lambda * tangent;
vA -= mA * P;
wA -= iA * MathUtils.Cross(vcp.rA, P);
vB += mB * P;
wB += iB * MathUtils.Cross(vcp.rB, P);
}
// Solve normal constraints
if (vc.pointCount == 1)
{
VelocityConstraintPoint vcp = vc.points[0];
// Relative velocity at contact
TSVector2 dv = vB + MathUtils.Cross(wB, vcp.rB) - vA - MathUtils.Cross(wA, vcp.rA);
// Compute normal impulse
FP vn = TSVector2.Dot(dv, normal);
FP lambda = -vcp.normalMass * (vn - vcp.velocityBias);
// b2Clamp the accumulated impulse
FP newImpulse = TrueSync.TSMath.Max(vcp.normalImpulse + lambda, 0.0f);
lambda = newImpulse - vcp.normalImpulse;
vcp.normalImpulse = newImpulse;
// Apply contact impulse
TSVector2 P = lambda * normal;
vA -= mA * P;
wA -= iA * MathUtils.Cross(vcp.rA, P);
vB += mB * P;
wB += iB * MathUtils.Cross(vcp.rB, P);
}
else
{
// Block solver developed in collaboration with Dirk Gregorius (back in 01/07 on Box2D_Lite).
// Build the mini LCP for this contact patch
//
// vn = A * x + b, vn >= 0, , vn >= 0, x >= 0 and vn_i * x_i = 0 with i = 1..2
//
// A = J * W * JT and J = ( -n, -r1 x n, n, r2 x n )
// b = vn0 - velocityBias
//
// The system is solved using the "Total enumeration method" (s. Murty). The complementary constraint vn_i * x_i
// implies that we must have in any solution either vn_i = 0 or x_i = 0. So for the 2D contact problem the cases
// vn1 = 0 and vn2 = 0, x1 = 0 and x2 = 0, x1 = 0 and vn2 = 0, x2 = 0 and vn1 = 0 need to be tested. The first valid
// solution that satisfies the problem is chosen.
//
// In order to account of the accumulated impulse 'a' (because of the iterative nature of the solver which only requires
// that the accumulated impulse is clamped and not the incremental impulse) we change the impulse variable (x_i).
//
// Substitute:
//
// x = a + d
//
// a := old total impulse
// x := new total impulse
// d := incremental impulse
//
// For the current iteration we extend the formula for the incremental impulse
// to compute the new total impulse:
//
// vn = A * d + b
// = A * (x - a) + b
// = A * x + b - A * a
// = A * x + b'
// b' = b - A * a;
VelocityConstraintPoint cp1 = vc.points[0];
VelocityConstraintPoint cp2 = vc.points[1];
TSVector2 a = new TSVector2(cp1.normalImpulse, cp2.normalImpulse);
Debug.Assert(a.x >= 0.0f && a.y >= 0.0f);
// Relative velocity at contact
TSVector2 dv1 = vB + MathUtils.Cross(wB, cp1.rB) - vA - MathUtils.Cross(wA, cp1.rA);
TSVector2 dv2 = vB + MathUtils.Cross(wB, cp2.rB) - vA - MathUtils.Cross(wA, cp2.rA);
// Compute normal velocity
FP vn1 = TSVector2.Dot(dv1, normal);
FP vn2 = TSVector2.Dot(dv2, normal);
TSVector2 b = new TSVector2();
b.x = vn1 - cp1.velocityBias;
b.y = vn2 - cp2.velocityBias;
// Compute b'
b -= MathUtils.Mul(ref vc.K, a);
//FP k_errorTol = 1e-3f;
//B2_NOT_USED(k_errorTol);
for (; ;)
{
//
// Case 1: vn = 0
//
// 0 = A * x + b'
//
// Solve for x:
//
// x = - inv(A) * b'
//
TSVector2 x = -MathUtils.Mul(ref vc.normalMass, b);
if (x.x >= 0.0f && x.y >= 0.0f)
{
// Get the incremental impulse
TSVector2 d = x - a;
// Apply incremental impulse
TSVector2 P1 = d.x * normal;
TSVector2 P2 = d.y * normal;
vA -= mA * (P1 + P2);
wA -= iA * (MathUtils.Cross(cp1.rA, P1) + MathUtils.Cross(cp2.rA, P2));
vB += mB * (P1 + P2);
wB += iB * (MathUtils.Cross(cp1.rB, P1) + MathUtils.Cross(cp2.rB, P2));
// Accumulate
cp1.normalImpulse = x.x;
cp2.normalImpulse = x.y;
#if B2_DEBUG_SOLVER
// Postconditions
dv1 = vB + MathUtils.Cross(wB, cp1.rB) - vA - MathUtils.Cross(wA, cp1.rA);
dv2 = vB + MathUtils.Cross(wB, cp2.rB) - vA - MathUtils.Cross(wA, cp2.rA);
// Compute normal velocity
vn1 = Vector2.Dot(dv1, normal);
vn2 = Vector2.Dot(dv2, normal);
b2Assert(b2Abs(vn1 - cp1.velocityBias) < k_errorTol);
b2Assert(b2Abs(vn2 - cp2.velocityBias) < k_errorTol);
#endif
break;
}
//
// Case 2: vn1 = 0 and x2 = 0
//
// 0 = a11 * x1 + a12 * 0 + b1'
// vn2 = a21 * x1 + a22 * 0 + b2'
//
x.x = -cp1.normalMass * b.x;
x.y = 0.0f;
vn1 = 0.0f;
vn2 = vc.K.ex.y * x.x + b.y;
if (x.x >= 0.0f && vn2 >= 0.0f)
{
// Get the incremental impulse
TSVector2 d = x - a;
// Apply incremental impulse
TSVector2 P1 = d.x * normal;
TSVector2 P2 = d.y * normal;
vA -= mA * (P1 + P2);
wA -= iA * (MathUtils.Cross(cp1.rA, P1) + MathUtils.Cross(cp2.rA, P2));
vB += mB * (P1 + P2);
wB += iB * (MathUtils.Cross(cp1.rB, P1) + MathUtils.Cross(cp2.rB, P2));
// Accumulate
cp1.normalImpulse = x.x;
cp2.normalImpulse = x.y;
#if B2_DEBUG_SOLVER
// Postconditions
dv1 = vB + MathUtils.Cross(wB, cp1.rB) - vA - MathUtils.Cross(wA, cp1.rA);
// Compute normal velocity
vn1 = Vector2.Dot(dv1, normal);
b2Assert(b2Abs(vn1 - cp1.velocityBias) < k_errorTol);
#endif
break;
}
//
// Case 3: vn2 = 0 and x1 = 0
//
// vn1 = a11 * 0 + a12 * x2 + b1'
// 0 = a21 * 0 + a22 * x2 + b2'
//
x.x = 0.0f;
x.y = -cp2.normalMass * b.y;
vn1 = vc.K.ey.x * x.y + b.x;
vn2 = 0.0f;
if (x.y >= 0.0f && vn1 >= 0.0f)
{
// Resubstitute for the incremental impulse
TSVector2 d = x - a;
// Apply incremental impulse
TSVector2 P1 = d.x * normal;
TSVector2 P2 = d.y * normal;
vA -= mA * (P1 + P2);
wA -= iA * (MathUtils.Cross(cp1.rA, P1) + MathUtils.Cross(cp2.rA, P2));
vB += mB * (P1 + P2);
wB += iB * (MathUtils.Cross(cp1.rB, P1) + MathUtils.Cross(cp2.rB, P2));
// Accumulate
cp1.normalImpulse = x.x;
cp2.normalImpulse = x.y;
#if B2_DEBUG_SOLVER
// Postconditions
dv2 = vB + MathUtils.Cross(wB, cp2.rB) - vA - MathUtils.Cross(wA, cp2.rA);
// Compute normal velocity
vn2 = Vector2.Dot(dv2, normal);
b2Assert(b2Abs(vn2 - cp2.velocityBias) < k_errorTol);
#endif
break;
}
//
// Case 4: x1 = 0 and x2 = 0
//
// vn1 = b1
// vn2 = b2;
x.x = 0.0f;
x.y = 0.0f;
vn1 = b.x;
vn2 = b.y;
if (vn1 >= 0.0f && vn2 >= 0.0f)
{
// Resubstitute for the incremental impulse
TSVector2 d = x - a;
// Apply incremental impulse
TSVector2 P1 = d.x * normal;
TSVector2 P2 = d.y * normal;
vA -= mA * (P1 + P2);
wA -= iA * (MathUtils.Cross(cp1.rA, P1) + MathUtils.Cross(cp2.rA, P2));
vB += mB * (P1 + P2);
wB += iB * (MathUtils.Cross(cp1.rB, P1) + MathUtils.Cross(cp2.rB, P2));
// Accumulate
cp1.normalImpulse = x.x;
cp2.normalImpulse = x.y;
break;
}
// No solution, give up. This is hit sometimes, but it doesn't seem to matter.
break;
}
}
_velocities[indexA].v = vA;
_velocities[indexA].w = wA;
_velocities[indexB].v = vB;
_velocities[indexB].w = wB;
}
}
public void InitializeVelocityConstraints()
{
for (int i = 0; i < _count; ++i)
{
ContactVelocityConstraint vc = _velocityConstraints[i];
ContactPositionConstraint pc = _positionConstraints[i];
FP radiusA = pc.radiusA;
FP radiusB = pc.radiusB;
Manifold manifold = _contacts[vc.contactIndex].Manifold;
int indexA = vc.indexA;
int indexB = vc.indexB;
FP mA = vc.invMassA;
FP mB = vc.invMassB;
FP iA = vc.invIA;
FP iB = vc.invIB;
TSVector2 localCenterA = pc.localCenterA;
TSVector2 localCenterB = pc.localCenterB;
TSVector2 cA = _positions[indexA].c;
FP aA = _positions[indexA].a;
TSVector2 vA = _velocities[indexA].v;
FP wA = _velocities[indexA].w;
TSVector2 cB = _positions[indexB].c;
FP aB = _positions[indexB].a;
TSVector2 vB = _velocities[indexB].v;
FP wB = _velocities[indexB].w;
Debug.Assert(manifold.PointCount > 0);
Transform xfA = new Transform();
Transform xfB = new Transform();
xfA.q.Set(aA);
xfB.q.Set(aB);
xfA.p = cA - MathUtils.Mul(xfA.q, localCenterA);
xfB.p = cB - MathUtils.Mul(xfB.q, localCenterB);
TSVector2 normal;
FixedArray2 <TSVector2> points;
WorldManifold.Initialize(ref manifold, ref xfA, radiusA, ref xfB, radiusB, out normal, out points);
vc.normal = normal;
int pointCount = vc.pointCount;
for (int j = 0; j < pointCount; ++j)
{
VelocityConstraintPoint vcp = vc.points[j];
vcp.rA = points[j] - cA;
vcp.rB = points[j] - cB;
FP rnA = MathUtils.Cross(vcp.rA, vc.normal);
FP rnB = MathUtils.Cross(vcp.rB, vc.normal);
FP kNormal = mA + mB + iA * rnA * rnA + iB * rnB * rnB;
vcp.normalMass = kNormal > 0.0f ? 1.0f / kNormal : 0.0f;
TSVector2 tangent = MathUtils.Cross(vc.normal, 1.0f);
FP rtA = MathUtils.Cross(vcp.rA, tangent);
FP rtB = MathUtils.Cross(vcp.rB, tangent);
FP kTangent = mA + mB + iA * rtA * rtA + iB * rtB * rtB;
vcp.tangentMass = kTangent > 0.0f ? 1.0f / kTangent : 0.0f;
// Setup a velocity bias for restitution.
vcp.velocityBias = 0.0f;
FP vRel = TSVector2.Dot(vc.normal, vB + MathUtils.Cross(wB, vcp.rB) - vA - MathUtils.Cross(wA, vcp.rA));
if (vRel < -Settings.VelocityThreshold)
{
vcp.velocityBias = -vc.restitution * vRel;
}
}
// If we have two points, then prepare the block solver.
if (vc.pointCount == 2)
{
VelocityConstraintPoint vcp1 = vc.points[0];
VelocityConstraintPoint vcp2 = vc.points[1];
FP rn1A = MathUtils.Cross(vcp1.rA, vc.normal);
FP rn1B = MathUtils.Cross(vcp1.rB, vc.normal);
FP rn2A = MathUtils.Cross(vcp2.rA, vc.normal);
FP rn2B = MathUtils.Cross(vcp2.rB, vc.normal);
FP k11 = mA + mB + iA * rn1A * rn1A + iB * rn1B * rn1B;
FP k22 = mA + mB + iA * rn2A * rn2A + iB * rn2B * rn2B;
FP k12 = mA + mB + iA * rn1A * rn2A + iB * rn1B * rn2B;
// Ensure a reasonable condition number.
FP k_maxConditionNumber = 1000.0f;
if (k11 * k11 < k_maxConditionNumber * (k11 * k22 - k12 * k12))
{
// K is safe to invert.
vc.K.ex = new TSVector2(k11, k12);
vc.K.ey = new TSVector2(k12, k22);
vc.normalMass = vc.K.Inverse;
}
else
{
// The constraints are redundant, just use one.
// TODO_ERIN use deepest?
vc.pointCount = 1;
}
}
}
}
