public Apple(Fixture connectedFixture, GameContent gameContent, World world)
{
this.world = world;
this.gameContent = gameContent;
texture = gameContent.apple;
fallenFromAir = false;
CreatBody();
State = LeafState.Grow;
if (connectedFixture != null)
{
this.connectedFixture = connectedFixture;
AABB aabb; connectedFixture.GetAABB(out aabb);
body.Position = aabb.GetCenter();
RevoluteJointDef rjd = new RevoluteJointDef();
rjd.bodyA = body;
rjd.bodyB = connectedFixture.GetBody();
rjd.localAnchorA = Vector2.Zero;
rjd.localAnchorB = connectedFixture.GetBody().GetLocalPoint(body.Position);
revoJoint = (RevoluteJoint)world.CreateJoint(rjd);
}
}
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;
}
}
public void Solve(ref TimeStep step, Vector2 gravity, bool allowSleep)
{
// Integrate velocities and apply damping.
for (int i = 0; i < _bodyCount; ++i)
{
Body b = _bodies[i];
if (b.GetType() != BodyType.Dynamic)
{
continue;
}
// Integrate velocities.
//Hack by Justin Dale to allow for an individual body to be immune to gravity.
if (b.noGravity)
{
b._linearVelocity += step.dt * (b._invMass * b._force);
}
else
{
b._linearVelocity += step.dt * (gravity + b._invMass * b._force);
}
b._angularVelocity += step.dt * b._invI * b._torque;
// Apply damping.
// ODE: dv/dt + c * v = 0
// Solution: v(t) = v0 * exp(-c * t)
// Time step: v(t + dt) = v0 * exp(-c * (t + dt)) = v0 * exp(-c * t) * exp(-c * dt) = v * exp(-c * dt)
// v2 = exp(-c * dt) * v1
// Taylor expansion:
// v2 = (1.0f - c * dt) * v1
b._linearVelocity *= MathUtils.Clamp(1.0f - step.dt * b._linearDamping, 0.0f, 1.0f);
b._angularVelocity *= MathUtils.Clamp(1.0f - step.dt * b._angularDamping, 0.0f, 1.0f);
}
// Partition contacts so that contacts with static bodies are solved last.
int i1 = -1;
for (int i2 = 0; i2 < _contactCount; ++i2)
{
Fixture fixtureA = _contacts[i2].GetFixtureA();
Fixture fixtureB = _contacts[i2].GetFixtureB();
Body bodyA = fixtureA.GetBody();
Body bodyB = fixtureB.GetBody();
bool nonStatic = bodyA.GetType() != BodyType.Static && bodyB.GetType() != BodyType.Static;
if (nonStatic)
{
++i1;
//b2Swap(_contacts[i1], _contacts[i2]);
Contact temp = _contacts[i1];
_contacts[i1] = _contacts[i2];
_contacts[i2] = temp;
}
}
// Initialize velocity constraints.
_contactSolver.Reset(_contacts, _contactCount, step.dtRatio);
_contactSolver.WarmStart();
for (int i = 0; i < _jointCount; ++i)
{
_joints[i].InitVelocityConstraints(ref step);
}
// Solve velocity constraints.
for (int i = 0; i < step.velocityIterations; ++i)
{
for (int j = 0; j < _jointCount; ++j)
{
_joints[j].SolveVelocityConstraints(ref step);
}
_contactSolver.SolveVelocityConstraints();
}
// Post-solve (store impulses for warm starting).
_contactSolver.StoreImpulses();
// Integrate positions.
for (int i = 0; i < _bodyCount; ++i)
{
Body b = _bodies[i];
if (b.GetType() == BodyType.Static)
{
continue;
}
// Check for large velocities.
Vector2 translation = step.dt * b._linearVelocity;
if (Vector2.Dot(translation, translation) > Settings.b2_maxTranslationSquared)
{
float ratio = Settings.b2_maxTranslation / translation.Length();
b._linearVelocity *= ratio;
}
float rotation = step.dt * b._angularVelocity;
if (rotation * rotation > Settings.b2_maxRotationSquared)
{
float ratio = Settings.b2_maxRotation / Math.Abs(rotation);
b._angularVelocity *= ratio;
}
// Store positions for continuous collision.
b._sweep.c0 = b._sweep.c;
b._sweep.a0 = b._sweep.a;
// Integrate
b._sweep.c += step.dt * b._linearVelocity;
b._sweep.a += step.dt * b._angularVelocity;
// Compute new transform
b.SynchronizeTransform();
// Note: shapes are synchronized later.
}
// Iterate over constraints.
for (int i = 0; i < step.positionIterations; ++i)
{
bool contactsOkay = _contactSolver.SolvePositionConstraints(Settings.b2_contactBaumgarte);
bool jointsOkay = true;
for (int j = 0; j < _jointCount; ++j)
{
bool jointOkay = _joints[j].SolvePositionConstraints(Settings.b2_contactBaumgarte);
jointsOkay = jointsOkay && jointOkay;
}
if (contactsOkay && jointsOkay)
{
// Exit early if the position errors are small.
break;
}
}
Report(_contactSolver._constraints);
if (allowSleep)
{
float minSleepTime = Settings.b2_maxFloat;
const float linTolSqr = Settings.b2_linearSleepTolerance * Settings.b2_linearSleepTolerance;
const float angTolSqr = Settings.b2_angularSleepTolerance * Settings.b2_angularSleepTolerance;
for (int i = 0; i < _bodyCount; ++i)
{
Body b = _bodies[i];
if (b.GetType() == BodyType.Static)
{
continue;
}
if ((b._flags & BodyFlags.AutoSleep) == 0)
{
b._sleepTime = 0.0f;
minSleepTime = 0.0f;
}
if ((b._flags & BodyFlags.AutoSleep) == 0 ||
b._angularVelocity * b._angularVelocity > angTolSqr ||
Vector2.Dot(b._linearVelocity, b._linearVelocity) > linTolSqr)
{
b._sleepTime = 0.0f;
minSleepTime = 0.0f;
}
else
{
b._sleepTime += step.dt;
minSleepTime = Math.Min(minSleepTime, b._sleepTime);
}
}
if (minSleepTime >= Settings.b2_timeToSleep)
{
for (int i = 0; i < _bodyCount; ++i)
{
Body b = _bodies[i];
b.SetAwake(false);
}
}
}
}
// Broad-phase callback.
internal void AddPair(FixtureProxy proxyA, FixtureProxy proxyB)
{
Fixture fixtureA = proxyA.fixture;
Fixture fixtureB = proxyB.fixture;
int indexA = proxyA.childIndex;
int indexB = proxyB.childIndex;
Body bodyA = fixtureA.GetBody();
Body bodyB = fixtureB.GetBody();
// Are the fixtures on the same body?
if (bodyA == bodyB)
{
return;
}
// Does a contact already exist?
ContactEdge edge = bodyB.GetContactList();
while (edge != null)
{
if (edge.Other == bodyA)
{
Fixture fA = edge.Contact.GetFixtureA();
Fixture fB = edge.Contact.GetFixtureB();
int iA = edge.Contact.GetChildIndexA();
int iB = edge.Contact.GetChildIndexB();
if (fA == fixtureA && fB == fixtureB && iA == indexA && iB == indexB)
{
// A contact already exists.
return;
}
if (fA == fixtureB && fB == fixtureA && iA == indexB && iB == indexA)
{
// A contact already exists.
return;
}
}
edge = edge.Next;
}
// Does a joint override collision? Is at least one body dynamic?
if (bodyB.ShouldCollide(bodyA) == false)
{
return;
}
// Check user filtering.
if (ContactFilter != null && ContactFilter.ShouldCollide(fixtureA, fixtureB) == false)
{
return;
}
// Call the factory.
Contact c = Contact.Create(fixtureA, indexA, fixtureB, indexB);
// Contact creation may swap fixtures.
fixtureA = c.GetFixtureA();
fixtureB = c.GetFixtureB();
indexA = c.GetChildIndexA();
indexB = c.GetChildIndexB();
bodyA = fixtureA.GetBody();
bodyB = fixtureB.GetBody();
// Insert into the world.
c._prev = null;
c._next = _contactList;
if (_contactList != null)
{
_contactList._prev = c;
}
_contactList = c;
// Connect to island graph.
// Connect to body A
c._nodeA.Contact = c;
c._nodeA.Other = bodyB;
c._nodeA.Prev = null;
c._nodeA.Next = bodyA._contactList;
if (bodyA._contactList != null)
{
bodyA._contactList.Prev = c._nodeA;
}
bodyA._contactList = c._nodeA;
// Connect to body B
c._nodeB.Contact = c;
c._nodeB.Other = bodyA;
c._nodeB.Prev = null;
c._nodeB.Next = bodyB._contactList;
if (bodyB._contactList != null)
{
bodyB._contactList.Prev = c._nodeB;
}
bodyB._contactList = c._nodeB;
++_contactCount;
}
internal void Collide()
{
// Update awake contacts.
Contact c = _contactList;
while (c != null)
{
Fixture fixtureA = c.GetFixtureA();
Fixture fixtureB = c.GetFixtureB();
int indexA = c.GetChildIndexA();
int indexB = c.GetChildIndexB();
Body bodyA = fixtureA.GetBody();
Body bodyB = fixtureB.GetBody();
if (bodyA.IsAwake() == false && bodyB.IsAwake() == false)
{
c = c.GetNext();
continue;
}
// Is this contact flagged for filtering?
if ((c._flags & ContactFlags.Filter) == ContactFlags.Filter)
{
// Should these bodies collide?
if (bodyB.ShouldCollide(bodyA) == false)
{
Contact cNuke = c;
c = cNuke.GetNext();
Destroy(cNuke);
continue;
}
// Check user filtering.
if (ContactFilter != null && ContactFilter.ShouldCollide(fixtureA, fixtureB) == false)
{
Contact cNuke = c;
c = cNuke.GetNext();
Destroy(cNuke);
continue;
}
// Clear the filtering flag.
c._flags &= ~ContactFlags.Filter;
}
int proxyIdA = fixtureA._proxies[indexA].proxyId;
int proxyIdB = fixtureB._proxies[indexB].proxyId;
bool overlap = _broadPhase.TestOverlap(proxyIdA, proxyIdB);
// Here we destroy contacts that cease to overlap in the broad-phase.
if (overlap == false)
{
Contact cNuke = c;
c = cNuke.GetNext();
Destroy(cNuke);
continue;
}
// The contact persists.
c.Update(ContactListener);
c = c.GetNext();
}
}
internal void Destroy(Contact c)
{
Fixture fixtureA = c.GetFixtureA();
Fixture fixtureB = c.GetFixtureB();
Body bodyA = fixtureA.GetBody();
Body bodyB = fixtureB.GetBody();
if (ContactListener != null && c.IsTouching())
{
ContactListener.EndContact(c);
}
// Remove from the world.
if (c._prev != null)
{
c._prev._next = c._next;
}
if (c._next != null)
{
c._next._prev = c._prev;
}
if (c == _contactList)
{
_contactList = c._next;
}
// Remove from body 1
if (c._nodeA.Prev != null)
{
c._nodeA.Prev.Next = c._nodeA.Next;
}
if (c._nodeA.Next != null)
{
c._nodeA.Next.Prev = c._nodeA.Prev;
}
if (c._nodeA == bodyA._contactList)
{
bodyA._contactList = c._nodeA.Next;
}
// Remove from body 2
if (c._nodeB.Prev != null)
{
c._nodeB.Prev.Next = c._nodeB.Next;
}
if (c._nodeB.Next != null)
{
c._nodeB.Next.Prev = c._nodeB.Prev;
}
if (c._nodeB == bodyB._contactList)
{
bodyB._contactList = c._nodeB.Next;
}
c.Destroy();
--_contactCount;
}
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;
}
}
