public void Initialize(Contact[] contacts, int count, Body toiBody)
{
_count = count;
_toiBody = toiBody;
if (_constraints.Length < _count)
{
_constraints = new TOIConstraint[Math.Max(_constraints.Length * 2, _count)];
}
for (int i = 0; i < _count; ++i)
{
Contact contact = contacts[i];
Fixture fixtureA = contact.GetFixtureA();
Fixture fixtureB = contact.GetFixtureB();
Shape shapeA = fixtureA.GetShape();
Shape shapeB = fixtureB.GetShape();
float radiusA = shapeA._radius;
float radiusB = shapeB._radius;
Body bodyA = fixtureA.GetBody();
Body bodyB = fixtureB.GetBody();
Manifold manifold;
contact.GetManifold(out manifold);
//Debug.Assert(manifold._pointCount > 0);
TOIConstraint constraint = _constraints[i];
constraint.bodyA = bodyA;
constraint.bodyB = bodyB;
constraint.localNormal = manifold._localNormal;
constraint.localPoint = manifold._localPoint;
constraint.type = manifold._type;
constraint.pointCount = manifold._pointCount;
constraint.radius = radiusA + radiusB;
for (int j = 0; j < constraint.pointCount; ++j)
{
constraint.localPoints[j] = manifold._points[j].LocalPoint;
}
_constraints[i] = constraint;
}
}
void PostSolve(Contact contact, ContactImpulse impulse)
{
if (m_broke)
{
// The body already broke.
return;
}
// Should the body break?
int count = contact.GetManifold().points.Count();
float maxImpulse = 0.0f;
for (int i = 0; i < count; ++i)
{
maxImpulse = Math.Max(maxImpulse, impulse.normalImpulses[i]);
}
if (maxImpulse > 40.0f)
{
// Flag the body for breaking.
m_break = true;
}
}
public void Reset(Contact[] contacts, int contactCount, float impulseRatio)
{
_contacts = contacts;
_constraintCount = contactCount;
// grow the array
if (_constraints == null || _constraints.Length < _constraintCount)
{
_constraints = new ContactConstraint[_constraintCount * 2];
}
for (int i = 0; i < _constraintCount; ++i)
{
Contact contact = contacts[i];
Fixture fixtureA = contact._fixtureA;
Fixture fixtureB = contact._fixtureB;
Shape shapeA = fixtureA.GetShape();
Shape shapeB = fixtureB.GetShape();
float radiusA = shapeA._radius;
float radiusB = shapeB._radius;
Body bodyA = fixtureA.GetBody();
Body bodyB = fixtureB.GetBody();
Manifold manifold;
contact.GetManifold(out manifold);
float friction = Settings.b2MixFriction(fixtureA.GetFriction(), fixtureB.GetFriction());
float restitution = Settings.b2MixRestitution(fixtureA.GetRestitution(), fixtureB.GetRestitution());
Vector2 vA = bodyA._linearVelocity;
Vector2 vB = bodyB._linearVelocity;
float wA = bodyA._angularVelocity;
float wB = bodyB._angularVelocity;
//Debug.Assert(manifold._pointCount > 0);
WorldManifold worldManifold = new WorldManifold(ref manifold, ref bodyA._xf, radiusA, ref bodyB._xf, radiusB);
ContactConstraint cc = _constraints[i];
cc.bodyA = bodyA;
cc.bodyB = bodyB;
cc.manifold = manifold;
cc.normal = worldManifold._normal;
cc.pointCount = manifold._pointCount;
cc.friction = friction;
cc.localNormal = manifold._localNormal;
cc.localPoint = manifold._localPoint;
cc.radius = radiusA + radiusB;
cc.type = manifold._type;
for (int j = 0; j < cc.pointCount; ++j)
{
ManifoldPoint cp = manifold._points[j];
ContactConstraintPoint ccp = cc.points[j];
ccp.normalImpulse = impulseRatio * cp.NormalImpulse;
ccp.tangentImpulse = impulseRatio * cp.TangentImpulse;
ccp.localPoint = cp.LocalPoint;
ccp.rA = worldManifold._points[j] - bodyA._sweep.c;
ccp.rB = worldManifold._points[j] - bodyB._sweep.c;
#if MATH_OVERLOADS
float rnA = MathUtils.Cross(ccp.rA, cc.normal);
float rnB = MathUtils.Cross(ccp.rB, cc.normal);
#else
float rnA = ccp.rA.x * cc.normal.y - ccp.rA.y * cc.normal.x;
float rnB = ccp.rB.x * cc.normal.y - ccp.rB.y * cc.normal.x;
#endif
rnA *= rnA;
rnB *= rnB;
float kNormal = bodyA._invMass + bodyB._invMass + bodyA._invI * rnA + bodyB._invI * rnB;
//Debug.Assert(kNormal > Settings.b2_epsilon);
ccp.normalMass = 1.0f / kNormal;
#if MATH_OVERLOADS
Vector2 tangent = MathUtils.Cross(cc.normal, 1.0f);
float rtA = MathUtils.Cross(ccp.rA, tangent);
float rtB = MathUtils.Cross(ccp.rB, tangent);
#else
Vector2 tangent = new Vector2(cc.normal.y, -cc.normal.x);
float rtA = ccp.rA.x * tangent.y - ccp.rA.y * tangent.x;
float rtB = ccp.rB.x * tangent.y - ccp.rB.y * tangent.x;
#endif
rtA *= rtA;
rtB *= rtB;
float kTangent = bodyA._invMass + bodyB._invMass + bodyA._invI * rtA + bodyB._invI * rtB;
//Debug.Assert(kTangent > Settings.b2_epsilon);
ccp.tangentMass = 1.0f / kTangent;
// Setup a velocity bias for restitution.
ccp.velocityBias = 0.0f;
float vRel = Vector2.Dot(cc.normal, vB + MathUtils.Cross(wB, ccp.rB) - vA - MathUtils.Cross(wA, ccp.rA));
if (vRel < -Settings.b2_velocityThreshold)
{
ccp.velocityBias = -restitution * vRel;
}
cc.points[j] = ccp;
}
// If we have two points, then prepare the block solver.
if (cc.pointCount == 2)
{
ContactConstraintPoint ccp1 = cc.points[0];
ContactConstraintPoint ccp2 = cc.points[1];
float invMassA = bodyA._invMass;
float invIA = bodyA._invI;
float invMassB = bodyB._invMass;
float invIB = bodyB._invI;
float rn1A = MathUtils.Cross(ccp1.rA, cc.normal);
float rn1B = MathUtils.Cross(ccp1.rB, cc.normal);
float rn2A = MathUtils.Cross(ccp2.rA, cc.normal);
float rn2B = MathUtils.Cross(ccp2.rB, cc.normal);
float k11 = invMassA + invMassB + invIA * rn1A * rn1A + invIB * rn1B * rn1B;
float k22 = invMassA + invMassB + invIA * rn2A * rn2A + invIB * rn2B * rn2B;
float k12 = invMassA + invMassB + invIA * rn1A * rn2A + invIB * rn1B * rn2B;
// Ensure a reasonable condition number.
const float k_maxConditionNumber = 100.0f;
if (k11 * k11 < k_maxConditionNumber * (k11 * k22 - k12 * k12))
{
// K is safe to invert.
cc.K = new Mat22(new Vector2(k11, k12), new Vector2(k12, k22));
cc.normalMass = cc.K.GetInverse();
}
else
{
// The constraints are redundant, just use one.
// TODO_ERIN use deepest?
cc.pointCount = 1;
}
}
_constraints[i] = cc;
}
}
public virtual void PreSolve(Contact contact, Manifold oldManifold) {
Manifold manifold = contact.GetManifold();
if (manifold.points.Count() == 0)
{
return;
}
Fixture fixtureA = contact.FixtureA;
Fixture fixtureB = contact.FixtureB;
PointState[] state1 = new PointState[Settings._maxManifoldPoints];
PointState[] state2 = new PointState[Settings._maxManifoldPoints];
Collision.GetPointStates(state1, state2, oldManifold, manifold);
WorldManifold worldManifold;
contact.GetWorldManifold(out worldManifold);
for (int i = 0; i < manifold.points.Count() && m_pointCount < Program.k_maxContactPoints; ++i)
{
ContactPoint cp = m_points[m_pointCount];
cp.fixtureA = fixtureA;
cp.fixtureB = fixtureB;
cp.position = worldManifold.points[i];
cp.normal = worldManifold.normal;
cp.state = state2[i];
cp.normalImpulse = manifold.points[i].normalImpulse;
cp.tangentImpulse = manifold.points[i].tangentImpulse;
++m_pointCount;
}
}
public ContactSolver(ContactSolverDef def)
{
m_step = def.step;
m_positionConstraints = new List <ContactPositionConstraint>();
m_velocityConstraints = new List <ContactVelocityConstraint>();
m_positions = def.positions;
m_velocities = def.velocities;
m_contacts = def.contacts;
// Initialize position independent portions of the constraints.
for (int i = 0; i < def.contacts.Count(); ++i)
{
Contact contact = m_contacts[i];
Fixture fixtureA = contact.m_fixtureA;
Fixture fixtureB = contact.m_fixtureB;
Shape shapeA = fixtureA.GetShape();
Shape shapeB = fixtureB.GetShape();
float radiusA = shapeA.m_radius;
float radiusB = shapeB.m_radius;
Body bodyA = fixtureA.GetBody();
Body bodyB = fixtureB.GetBody();
Manifold manifold = contact.GetManifold();
int pointCount = manifold.points.Count();
Utilities.Assert(pointCount > 0);
ContactVelocityConstraint vc = new ContactVelocityConstraint();
vc.friction = contact.m_friction;
vc.restitution = contact.m_restitution;
vc.tangentSpeed = contact.m_tangentSpeed;
vc.indexA = bodyA.m_islandIndex;
vc.indexB = bodyB.m_islandIndex;
vc.invMassA = bodyA.m_invMass;
vc.invMassB = bodyB.m_invMass;
vc.invIA = bodyA.m_invI;
vc.invIB = bodyB.m_invI;
vc.contactIndex = i;
//vc.points.Count() = pointCount;
vc.K.SetZero();
vc.normalMass.SetZero();
ContactPositionConstraint pc = new ContactPositionConstraint();
pc.indexA = bodyA.m_islandIndex;
pc.indexB = bodyB.m_islandIndex;
pc.invMassA = bodyA.m_invMass;
pc.invMassB = bodyB.m_invMass;
pc.localCenterA = bodyA.m_sweep.localCenter;
pc.localCenterB = bodyB.m_sweep.localCenter;
pc.invIA = bodyA.m_invI;
pc.invIB = bodyB.m_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 = new VelocityConstraintPoint();
if (m_step.warmStarting)
{
vcp.normalImpulse = m_step.dtRatio * cp.normalImpulse;
vcp.tangentImpulse = m_step.dtRatio * cp.tangentImpulse;
}
else
{
vcp.normalImpulse = 0.0f;
vcp.tangentImpulse = 0.0f;
}
vcp.rA.SetZero();
vcp.rB.SetZero();
vcp.normalMass = 0.0f;
vcp.tangentMass = 0.0f;
vcp.velocityBias = 0.0f;
vc.points.Add(vcp);
pc.localPoints[j] = cp.localPoint;
}
m_velocityConstraints.Add(vc);
m_positionConstraints.Add(pc);
}
}
