/// <summary>
/// Initialize the bodies, anchors, lengths, max lengths, and ratio using the world anchors.
/// This requires two ground anchors,
/// two dynamic body anchor points, max lengths for each side,
/// and a pulley ratio.
/// </summary>
/// <param name="bA">The first body.</param>
/// <param name="bB">The second body.</param>
/// <param name="groundA">The ground anchor for the first body.</param>
/// <param name="groundB">The ground anchor for the second body.</param>
/// <param name="anchorA">The first body anchor.</param>
/// <param name="anchorB">The second body anchor.</param>
/// <param name="ratio">The ratio.</param>
public FSPulleyJoint(FSBody bA, FSBody bB, FVector2 groundA, FVector2 groundB, FVector2 anchorA, FVector2 anchorB, float ratio)
: base(bA, bB)
{
JointType = JointType.Pulley;
GroundAnchorA = groundA;
GroundAnchorB = groundB;
LocalAnchorA = anchorA;
LocalAnchorB = anchorB;
Debug.Assert(ratio != 0.0f);
Debug.Assert(ratio > FSSettings.Epsilon);
Ratio = ratio;
FVector2 dA = BodyA.GetWorldPoint(anchorA) - groundA;
LengthA = dA.Length();
FVector2 dB = BodyB.GetWorldPoint(anchorB) - groundB;
LengthB = dB.Length();
m_constant = LengthA + ratio * LengthB;
_impulse = 0.0f;
}
internal override void SolveVelocityConstraints(ref SolverData data)
{
FVector2 vB = data.velocities[_indexB].v;
float wB = data.velocities[_indexB].w;
// Cdot = v + cross(w, r)
FVector2 Cdot = vB + MathUtils.Cross(wB, _rB);
FVector2 impulse = MathUtils.Mul(ref _mass, -(Cdot + _C + _gamma * _impulse));
FVector2 oldImpulse = _impulse;
_impulse += impulse;
float maxImpulse = data.step.dt * MaxForce;
if (_impulse.LengthSquared() > maxImpulse * maxImpulse)
{
_impulse *= maxImpulse / _impulse.Length();
}
impulse = _impulse - oldImpulse;
vB += _invMassB * impulse;
wB += _invIB * MathUtils.Cross(_rB, impulse);
data.velocities[_indexB].v = vB;
data.velocities[_indexB].w = wB;
}
public PolyNode GetRightestConnection(PolyNode incoming)
{
if (NConnected == 0)
{
Debug.Assert(false); // This means the connection graph is inconsistent
}
if (NConnected == 1)
{
//b2Assert(false);
// Because of the possibility of collapsing nearby points,
// we may end up with "spider legs" dangling off of a region.
// The correct behavior here is to turn around.
return(incoming);
}
FVector2 inDir = Position - incoming.Position;
float inLength = inDir.Length();
inDir.Normalize();
Debug.Assert(inLength > Settings.Epsilon);
PolyNode result = null;
for (int i = 0; i < NConnected; ++i)
{
if (Connected[i] == incoming)
{
continue;
}
FVector2 testDir = Connected[i].Position - Position;
float testLengthSqr = testDir.LengthSquared();
testDir.Normalize();
Debug.Assert(testLengthSqr >= Settings.Epsilon * Settings.Epsilon);
float myCos = FVector2.Dot(inDir, testDir);
float mySin = MathUtils.Cross(inDir, testDir);
if (result != null)
{
FVector2 resultDir = result.Position - Position;
resultDir.Normalize();
float resCos = FVector2.Dot(inDir, resultDir);
float resSin = MathUtils.Cross(inDir, resultDir);
if (IsRighter(mySin, myCos, resSin, resCos))
{
result = Connected[i];
}
}
else
{
result = Connected[i];
}
}
Debug.Assert(result != null);
return(result);
}
internal override bool SolvePositionConstraints(ref SolverData data)
{
if (Frequency > 0.0f)
{
// There is no position correction for soft distance constraints.
return(true);
}
FSBody b1 = BodyA;
FSBody b2 = BodyB;
Transform xf1, xf2;
b1.GetTransform(out xf1);
b2.GetTransform(out xf2);
FVector2 r1 = MathUtils.Mul(ref xf1.q, LocalAnchorA - b1.LocalCenter);
FVector2 r2 = MathUtils.Mul(ref xf2.q, LocalAnchorB - b2.LocalCenter);
FVector2 d = b2.Sweep.C + r2 - b1.Sweep.C - r1;
float length = d.Length();
if (length < MaxLength && length > MinLength)
{
return(true);
}
if (length == 0.0f)
{
return(true);
}
d /= length;
float C = length - MaxLength;
C = MathUtils.Clamp(C, -FSSettings.MaxLinearCorrection, FSSettings.MaxLinearCorrection);
float impulse = -_mass * C;
_u = d;
FVector2 P = impulse * _u;
b1.Sweep.C -= b1.InvMass * P;
b1.Sweep.A -= b1.InvI * MathUtils.Cross(r1, P);
b2.Sweep.C += b2.InvMass * P;
b2.Sweep.A += b2.InvI * MathUtils.Cross(r2, P);
b1.SynchronizeTransform();
b2.SynchronizeTransform();
return(Math.Abs(C) < FSSettings.LinearSlop);
}
public FSRopeJoint(FSBody bodyA, FSBody bodyB, FVector2 localAnchorA, FVector2 localAnchorB)
: base(bodyA, bodyB)
{
JointType = JointType.Rope;
LocalAnchorA = localAnchorA;
LocalAnchorB = localAnchorB;
//FPE: Setting default MaxLength
FVector2 d = WorldAnchorB - WorldAnchorA;
MaxLength = d.Length();
}
/// <summary>
/// This requires defining an
/// anchor point on both bodies and the non-zero length of the
/// distance joint. If you don't supply a length, the local anchor points
/// is used so that the initial configuration can violate the constraint
/// slightly. This helps when saving and loading a game.
/// @warning Do not use a zero or short length.
/// </summary>
/// <param name="bodyA">The first body</param>
/// <param name="bodyB">The second body</param>
/// <param name="localAnchorA">The first body anchor</param>
/// <param name="localAnchorB">The second body anchor</param>
public DistanceJoint(Body bodyA, Body bodyB, FVector2 localAnchorA, FVector2 localAnchorB)
: base(bodyA, bodyB)
{
JointType = JointType.Distance;
LocalAnchorA = localAnchorA;
LocalAnchorB = localAnchorB;
FVector2 d = WorldAnchorB - WorldAnchorA;
Length = d.Length();
}
/// <summary>
/// tests if ray intersects AABB
/// </summary>
/// <param name="aabb"></param>
/// <returns></returns>
public static bool RayCastAABB(AABB aabb, FVector2 p1, FVector2 p2)
{
AABB segmentAABB = new AABB();
{
FVector2.Min(ref p1, ref p2, out segmentAABB.LowerBound);
FVector2.Max(ref p1, ref p2, out segmentAABB.UpperBound);
}
if (!AABB.TestOverlap(aabb, segmentAABB))
{
return(false);
}
FVector2 rayDir = p2 - p1;
FVector2 rayPos = p1;
FVector2 norm = new FVector2(-rayDir.Y, rayDir.X); //normal to ray
if (norm.Length() == 0.0)
{
return(true); //if ray is just a point, return true (iff point is within aabb, as tested earlier)
}
norm.Normalize();
float dPos = FVector2.Dot(rayPos, norm);
FVector2[] verts = aabb.GetVertices();
float d0 = FVector2.Dot(verts[0], norm) - dPos;
for (int i = 1; i < 4; i++)
{
float d = FVector2.Dot(verts[i], norm) - dPos;
if (Math.Sign(d) != Math.Sign(d0))
{
//return true if the ray splits the vertices (ie: sign of dot products with normal are not all same)
return(true);
}
}
return(false);
}
internal override bool SolvePositionConstraints(ref SolverData data)
{
if (Frequency > 0.0f)
{
// There is no position correction for soft distance constraints.
return(true);
}
FVector2 cA = data.positions[m_indexA].c;
float aA = data.positions[m_indexA].a;
FVector2 cB = data.positions[m_indexB].c;
float aB = data.positions[m_indexB].a;
Rot qA = new Rot(aA), qB = new Rot(aB);
FVector2 rA = MathUtils.Mul(qA, LocalAnchorA - m_localCenterA);
FVector2 rB = MathUtils.Mul(qB, LocalAnchorB - m_localCenterB);
FVector2 u = cB + rB - cA - rA;
float length = u.Length(); u.Normalize();
float C = length - Length;
C = MathUtils.Clamp(C, -Settings.MaxLinearCorrection, Settings.MaxLinearCorrection);
float impulse = -_mass * C;
FVector2 P = impulse * u;
cA -= m_invMassA * P;
aA -= m_invIA * MathUtils.Cross(rA, P);
cB += m_invMassB * P;
aB += m_invIB * MathUtils.Cross(rB, P);
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
return(Math.Abs(C) < Settings.LinearSlop);
}
internal override void SolveVelocityConstraints(ref SolverData data)
{
FSBody b1 = BodyA;
FSBody b2 = BodyB;
Transform xf1, xf2;
b1.GetTransform(out xf1);
b2.GetTransform(out xf2);
FVector2 r1 = MathUtils.Mul(ref xf1.q, LocalAnchorA - b1.LocalCenter);
FVector2 r2 = MathUtils.Mul(ref xf2.q, LocalAnchorB - b2.LocalCenter);
FVector2 d = b2.Sweep.C + r2 - b1.Sweep.C - r1;
float length = d.Length();
if (length < MaxLength && length > MinLength)
{
return;
}
// Cdot = dot(u, v + cross(w, r))
FVector2 v1 = b1.LinearVelocityInternal + MathUtils.Cross(b1.AngularVelocityInternal, r1);
FVector2 v2 = b2.LinearVelocityInternal + MathUtils.Cross(b2.AngularVelocityInternal, r2);
float Cdot = FVector2.Dot(_u, v2 - v1);
float impulse = -_mass * (Cdot + _bias + _gamma * _impulse);
_impulse += impulse;
FVector2 P = impulse * _u;
b1.LinearVelocityInternal -= b1.InvMass * P;
b1.AngularVelocityInternal -= b1.InvI * MathUtils.Cross(r1, P);
b2.LinearVelocityInternal += b2.InvMass * P;
b2.AngularVelocityInternal += b2.InvI * MathUtils.Cross(r2, P);
}
internal override bool SolvePositionConstraints(ref SolverData data)
{
FVector2 cA = data.positions[_indexA].c;
float aA = data.positions[_indexA].a;
FVector2 cB = data.positions[_indexB].c;
float aB = data.positions[_indexB].a;
Rot qA = new Rot(aA), qB = new Rot(aB);
FVector2 rA = MathUtils.Mul(qA, LocalAnchorA - _localCenterA);
FVector2 rB = MathUtils.Mul(qB, LocalAnchorB - _localCenterB);
FVector2 u = cB + rB - cA - rA;
float length = u.Length();
u.Normalize();
float C = length - MaxLength;
C = MathUtils.Clamp(C, 0.0f, FSSettings.MaxLinearCorrection);
float impulse = -_mass * C;
FVector2 P = impulse * u;
cA -= _invMassA * P;
aA -= _invIA * MathUtils.Cross(rA, P);
cB += _invMassB * P;
aB += _invIB * MathUtils.Cross(rB, P);
data.positions[_indexA].c = cA;
data.positions[_indexA].a = aA;
data.positions[_indexB].c = cB;
data.positions[_indexB].a = aB;
return(length - MaxLength < FSSettings.LinearSlop);
}
internal override void InitVelocityConstraints(ref SolverData data)
{
Body b1 = BodyA;
Body b2 = BodyB;
Transform xf1, xf2;
b1.GetTransform(out xf1);
b2.GetTransform(out xf2);
// Compute the effective mass matrix.
FVector2 r1 = MathUtils.Mul(ref xf1.q, LocalAnchorA - b1.LocalCenter);
FVector2 r2 = MathUtils.Mul(ref xf2.q, LocalAnchorB - b2.LocalCenter);
_u = b2.Sweep.C + r2 - b1.Sweep.C - r1;
// Handle singularity.
float length = _u.Length();
if (length < MaxLength && length > MinLength)
{
return;
}
if (length > Settings.LinearSlop)
{
_u *= 1.0f / length;
}
else
{
_u = FVector2.Zero;
}
float cr1u = MathUtils.Cross(r1, _u);
float cr2u = MathUtils.Cross(r2, _u);
float invMass = b1.InvMass + b1.InvI * cr1u * cr1u + b2.InvMass + b2.InvI * cr2u * cr2u;
Debug.Assert(invMass > Settings.Epsilon);
_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
if (Frequency > 0.0f)
{
float C = length - MaxLength;
// Frequency
float omega = 2.0f * Settings.Pi * Frequency;
// Damping coefficient
float d = 2.0f * _mass * DampingRatio * omega;
// Spring stiffness
float k = _mass * omega * omega;
// magic formulas
_gamma = data.step.dt * (d + data.step.dt * k);
_gamma = _gamma != 0.0f ? 1.0f / _gamma : 0.0f;
_bias = C * data.step.dt * k * _gamma;
_mass = invMass + _gamma;
_mass = _mass != 0.0f ? 1.0f / _mass : 0.0f;
}
if (Settings.EnableWarmstarting)
{
// Scale the impulse to support a variable time step.
_impulse *= data.step.dtRatio;
FVector2 P = _impulse * _u;
b1.LinearVelocityInternal -= b1.InvMass * P;
b1.AngularVelocityInternal -= b1.InvI * MathUtils.Cross(r1, P);
b2.LinearVelocityInternal += b2.InvMass * P;
b2.AngularVelocityInternal += b2.InvI * MathUtils.Cross(r2, P);
}
else
{
_impulse = 0.0f;
}
}
internal override void InitVelocityConstraints(ref SolverData data)
{
_indexA = BodyA.IslandIndex;
_indexB = BodyB.IslandIndex;
_localCenterA = BodyA.Sweep.LocalCenter;
_localCenterB = BodyB.Sweep.LocalCenter;
_invMassA = BodyA.InvMass;
_invMassB = BodyB.InvMass;
_invIA = BodyA.InvI;
_invIB = BodyB.InvI;
FVector2 cA = data.positions[_indexA].c;
float aA = data.positions[_indexA].a;
FVector2 vA = data.velocities[_indexA].v;
float wA = data.velocities[_indexA].w;
FVector2 cB = data.positions[_indexB].c;
float aB = data.positions[_indexB].a;
FVector2 vB = data.velocities[_indexB].v;
float wB = data.velocities[_indexB].w;
Rot qA = new Rot(aA), qB = new Rot(aB);
_rA = MathUtils.Mul(qA, LocalAnchorA - _localCenterA);
_rB = MathUtils.Mul(qB, LocalAnchorB - _localCenterB);
_u = cB + _rB - cA - _rA;
_length = _u.Length();
float C = _length - MaxLength;
if (C > 0.0f)
{
_state = LimitState.AtUpper;
}
else
{
_state = LimitState.Inactive;
}
if (_length > Settings.LinearSlop)
{
_u *= 1.0f / _length;
}
else
{
_u = FVector2.Zero;
_mass = 0.0f;
_impulse = 0.0f;
return;
}
// Compute effective mass.
float crA = MathUtils.Cross(_rA, _u);
float crB = MathUtils.Cross(_rB, _u);
float invMass = _invMassA + _invIA * crA * crA + _invMassB + _invIB * crB * crB;
_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
if (Settings.EnableWarmstarting)
{
// Scale the impulse to support a variable time step.
_impulse *= data.step.dtRatio;
FVector2 P = _impulse * _u;
vA -= _invMassA * P;
wA -= _invIA * MathUtils.Cross(_rA, P);
vB += _invMassB * P;
wB += _invIB * MathUtils.Cross(_rB, P);
}
else
{
_impulse = 0.0f;
}
data.velocities[_indexA].v = vA;
data.velocities[_indexA].w = wA;
data.velocities[_indexB].v = vB;
data.velocities[_indexB].w = wB;
}
internal override bool SolvePositionConstraints(ref SolverData data)
{
FVector2 cA = data.positions[m_indexA].c;
float aA = data.positions[m_indexA].a;
FVector2 cB = data.positions[m_indexB].c;
float aB = data.positions[m_indexB].a;
Rot qA = new Rot(aA), qB = new Rot(aB);
FVector2 rA = MathUtils.Mul(qA, LocalAnchorA - m_localCenterA);
FVector2 rB = MathUtils.Mul(qB, LocalAnchorB - m_localCenterB);
// Get the pulley axes.
FVector2 uA = cA + rA - GroundAnchorA;
FVector2 uB = cB + rB - GroundAnchorB;
float lengthA = uA.Length();
float lengthB = uB.Length();
if (lengthA > 10.0f * FSSettings.LinearSlop)
{
uA *= 1.0f / lengthA;
}
else
{
uA = FVector2.Zero;
}
if (lengthB > 10.0f * FSSettings.LinearSlop)
{
uB *= 1.0f / lengthB;
}
else
{
uB = FVector2.Zero;
}
// Compute effective mass.
float ruA = MathUtils.Cross(rA, uA);
float ruB = MathUtils.Cross(rB, uB);
float mA = m_invMassA + m_invIA * ruA * ruA;
float mB = m_invMassB + m_invIB * ruB * ruB;
float mass = mA + Ratio * Ratio * mB;
if (mass > 0.0f)
{
mass = 1.0f / mass;
}
float C = m_constant - lengthA - Ratio * lengthB;
float linearError = Math.Abs(C);
float impulse = -mass * C;
FVector2 PA = -impulse * uA;
FVector2 PB = -Ratio * impulse * uB;
cA += m_invMassA * PA;
aA += m_invIA * MathUtils.Cross(rA, PA);
cB += m_invMassB * PB;
aB += m_invIB * MathUtils.Cross(rB, PB);
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
return(linearError < FSSettings.LinearSlop);
}
internal override void InitVelocityConstraints(ref SolverData data)
{
m_indexA = BodyA.IslandIndex;
m_indexB = BodyB.IslandIndex;
m_localCenterA = BodyA.Sweep.LocalCenter;
m_localCenterB = BodyB.Sweep.LocalCenter;
m_invMassA = BodyA.InvMass;
m_invMassB = BodyB.InvMass;
m_invIA = BodyA.InvI;
m_invIB = BodyB.InvI;
FVector2 cA = data.positions[m_indexA].c;
float aA = data.positions[m_indexA].a;
FVector2 vA = data.velocities[m_indexA].v;
float wA = data.velocities[m_indexA].w;
FVector2 cB = data.positions[m_indexB].c;
float aB = data.positions[m_indexB].a;
FVector2 vB = data.velocities[m_indexB].v;
float wB = data.velocities[m_indexB].w;
Rot qA = new Rot(aA), qB = new Rot(aB);
m_rA = MathUtils.Mul(qA, LocalAnchorA - m_localCenterA);
m_rB = MathUtils.Mul(qB, LocalAnchorB - m_localCenterB);
// Get the pulley axes.
m_uA = cA + m_rA - GroundAnchorA;
m_uB = cB + m_rB - GroundAnchorB;
float lengthA = m_uA.Length();
float lengthB = m_uB.Length();
if (lengthA > 10.0f * FSSettings.LinearSlop)
{
m_uA *= 1.0f / lengthA;
}
else
{
m_uA = FVector2.Zero;
}
if (lengthB > 10.0f * FSSettings.LinearSlop)
{
m_uB *= 1.0f / lengthB;
}
else
{
m_uB = FVector2.Zero;
}
// Compute effective mass.
float ruA = MathUtils.Cross(m_rA, m_uA);
float ruB = MathUtils.Cross(m_rB, m_uB);
float mA = m_invMassA + m_invIA * ruA * ruA;
float mB = m_invMassB + m_invIB * ruB * ruB;
m_mass = mA + Ratio * Ratio * mB;
if (m_mass > 0.0f)
{
m_mass = 1.0f / m_mass;
}
if (FSSettings.EnableWarmstarting)
{
// Scale impulses to support variable time steps.
_impulse *= data.step.dtRatio;
// Warm starting.
FVector2 PA = -(_impulse + _limitImpulse1) * m_uA;
FVector2 PB = (-Ratio * _impulse - _limitImpulse2) * m_uB;
vA += m_invMassA * PA;
wA += m_invIA * MathUtils.Cross(m_rA, PA);
vB += m_invMassB * PB;
wB += m_invIB * MathUtils.Cross(m_rB, PB);
}
else
{
_impulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
internal override void InitVelocityConstraints(ref SolverData data)
{
m_indexA = BodyA.IslandIndex;
m_indexB = BodyB.IslandIndex;
m_localCenterA = BodyA.Sweep.LocalCenter;
m_localCenterB = BodyB.Sweep.LocalCenter;
m_invMassA = BodyA.InvMass;
m_invMassB = BodyB.InvMass;
m_invIA = BodyA.InvI;
m_invIB = BodyB.InvI;
FVector2 cA = data.positions[m_indexA].c;
float aA = data.positions[m_indexA].a;
FVector2 vA = data.velocities[m_indexA].v;
float wA = data.velocities[m_indexA].w;
FVector2 cB = data.positions[m_indexB].c;
float aB = data.positions[m_indexB].a;
FVector2 vB = data.velocities[m_indexB].v;
float wB = data.velocities[m_indexB].w;
Rot qA = new Rot(aA), qB = new Rot(aB);
m_rA = MathUtils.Mul(qA, LocalAnchorA - m_localCenterA);
m_rB = MathUtils.Mul(qB, LocalAnchorB - m_localCenterB);
_u = cB + m_rB - cA - m_rA;
// Handle singularity.
float length = _u.Length();
if (length > Settings.LinearSlop)
{
_u *= 1.0f / length;
}
else
{
_u = FVector2.Zero;
}
float crAu = MathUtils.Cross(m_rA, _u);
float crBu = MathUtils.Cross(m_rB, _u);
float invMass = m_invMassA + m_invIA * crAu * crAu + m_invMassB + m_invIB * crBu * crBu;
// Compute the effective mass matrix.
_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
if (Frequency > 0.0f)
{
float C = length - Length;
// Frequency
float omega = 2.0f * Settings.Pi * Frequency;
// Damping coefficient
float d = 2.0f * _mass * DampingRatio * omega;
// Spring stiffness
float k = _mass * omega * omega;
// magic formulas
float h = data.step.dt;
_gamma = h * (d + h * k);
_gamma = _gamma != 0.0f ? 1.0f / _gamma : 0.0f;
_bias = C * h * k * _gamma;
invMass += _gamma;
_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
}
else
{
_gamma = 0.0f;
_bias = 0.0f;
}
if (Settings.EnableWarmstarting)
{
// Scale the impulse to support a variable time step.
_impulse *= data.step.dtRatio;
FVector2 P = _impulse * _u;
vA -= m_invMassA * P;
wA -= m_invIA * MathUtils.Cross(m_rA, P);
vB += m_invMassB * P;
wB += m_invIB * MathUtils.Cross(m_rB, P);
}
else
{
_impulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
internal override void SolveVelocityConstraints(ref SolverData data)
{
FVector2 vB = data.velocities[_indexB].v;
float wB = data.velocities[_indexB].w;
// Cdot = v + cross(w, r)
FVector2 Cdot = vB + MathUtils.Cross(wB, _rB);
FVector2 impulse = MathUtils.Mul(ref _mass, -(Cdot + _C + _gamma * _impulse));
FVector2 oldImpulse = _impulse;
_impulse += impulse;
float maxImpulse = data.step.dt * MaxForce;
if (_impulse.LengthSquared() > maxImpulse * maxImpulse)
{
_impulse *= maxImpulse / _impulse.Length();
}
impulse = _impulse - oldImpulse;
vB += _invMassB * impulse;
wB += _invIB * MathUtils.Cross(_rB, impulse);
data.velocities[_indexB].v = vB;
data.velocities[_indexB].w = wB;
}
internal override bool SolvePositionConstraints(ref SolverData data)
{
FVector2 cA = data.positions[m_indexA].c;
float aA = data.positions[m_indexA].a;
FVector2 cB = data.positions[m_indexB].c;
float aB = data.positions[m_indexB].a;
Rot qA = new Rot(aA), qB = new Rot(aB);
float mA = m_invMassA, mB = m_invMassB;
float iA = m_invIA, iB = m_invIB;
FVector2 rA = MathUtils.Mul(qA, LocalAnchorA - m_localCenterA);
FVector2 rB = MathUtils.Mul(qB, LocalAnchorB - m_localCenterB);
float positionError, angularError;
Mat33 K = new Mat33();
K.ex.X = mA + mB + rA.Y * rA.Y * iA + rB.Y * rB.Y * iB;
K.ey.X = -rA.Y * rA.X * iA - rB.Y * rB.X * iB;
K.ez.X = -rA.Y * iA - rB.Y * iB;
K.ex.Y = K.ey.X;
K.ey.Y = mA + mB + rA.X * rA.X * iA + rB.X * rB.X * iB;
K.ez.Y = rA.X * iA + rB.X * iB;
K.ex.Z = K.ez.X;
K.ey.Z = K.ez.Y;
K.ez.Z = iA + iB;
if (m_frequencyHz > 0.0f)
{
FVector2 C1 = cB + rB - cA - rA;
positionError = C1.Length();
angularError = 0.0f;
FVector2 P = -K.Solve22(C1);
cA -= mA * P;
aA -= iA * MathUtils.Cross(rA, P);
cB += mB * P;
aB += iB * MathUtils.Cross(rB, P);
}
else
{
FVector2 C1 = cB + rB - cA - rA;
float C2 = aB - aA - ReferenceAngle;
positionError = C1.Length();
angularError = Math.Abs(C2);
FVector3 C = new FVector3(C1.X, C1.Y, C2);
FVector3 impulse = -K.Solve33(C);
FVector2 P = new FVector2(impulse.X, impulse.Y);
cA -= mA * P;
aA -= iA * (MathUtils.Cross(rA, P) + impulse.Z);
cB += mB * P;
aB += iB * (MathUtils.Cross(rB, P) + impulse.Z);
}
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
return(positionError <= Settings.LinearSlop && angularError <= Settings.AngularSlop);
}
internal override bool SolvePositionConstraints(ref SolverData data)
{
FVector2 cA = data.positions[m_indexA].c;
float aA = data.positions[m_indexA].a;
FVector2 cB = data.positions[m_indexB].c;
float aB = data.positions[m_indexB].a;
Rot qA = new Rot(aA), qB = new Rot(aB);
float angularError = 0.0f;
float positionError;
bool fixedRotation = (m_invIA + m_invIB == 0.0f);
// Solve angular limit constraint.
if (_enableLimit && _limitState != LimitState.Inactive && fixedRotation == false)
{
float angle = aB - aA - ReferenceAngle;
float limitImpulse = 0.0f;
if (_limitState == LimitState.Equal)
{
// Prevent large angular corrections
float C = MathUtils.Clamp(angle - _lowerAngle, -FSSettings.MaxAngularCorrection, FSSettings.MaxAngularCorrection);
limitImpulse = -m_motorMass * C;
angularError = Math.Abs(C);
}
else if (_limitState == LimitState.AtLower)
{
float C = angle - _lowerAngle;
angularError = -C;
// Prevent large angular corrections and allow some slop.
C = MathUtils.Clamp(C + FSSettings.AngularSlop, -FSSettings.MaxAngularCorrection, 0.0f);
limitImpulse = -m_motorMass * C;
}
else if (_limitState == LimitState.AtUpper)
{
float C = angle - _upperAngle;
angularError = C;
// Prevent large angular corrections and allow some slop.
C = MathUtils.Clamp(C - FSSettings.AngularSlop, 0.0f, FSSettings.MaxAngularCorrection);
limitImpulse = -m_motorMass * C;
}
aA -= m_invIA * limitImpulse;
aB += m_invIB * limitImpulse;
}
// Solve point-to-point constraint.
{
qA.Set(aA);
qB.Set(aB);
FVector2 rA = MathUtils.Mul(qA, LocalAnchorA - m_localCenterA);
FVector2 rB = MathUtils.Mul(qB, LocalAnchorB - m_localCenterB);
FVector2 C = cB + rB - cA - rA;
positionError = C.Length();
float mA = m_invMassA, mB = m_invMassB;
float iA = m_invIA, iB = m_invIB;
Mat22 K = new Mat22();
K.ex.X = mA + mB + iA * rA.Y * rA.Y + iB * rB.Y * rB.Y;
K.ex.Y = -iA * rA.X * rA.Y - iB * rB.X * rB.Y;
K.ey.X = K.ex.Y;
K.ey.Y = mA + mB + iA * rA.X * rA.X + iB * rB.X * rB.X;
FVector2 impulse = -K.Solve(C);
cA -= mA * impulse;
aA -= iA * MathUtils.Cross(rA, impulse);
cB += mB * impulse;
aB += iB * MathUtils.Cross(rB, impulse);
}
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
return(positionError <= FSSettings.LinearSlop && angularError <= FSSettings.AngularSlop);
}
internal override void InitVelocityConstraints(ref SolverData data)
{
m_indexA = BodyA.IslandIndex;
m_indexB = BodyB.IslandIndex;
m_localCenterA = BodyA.Sweep.LocalCenter;
m_localCenterB = BodyB.Sweep.LocalCenter;
m_invMassA = BodyA.InvMass;
m_invMassB = BodyB.InvMass;
m_invIA = BodyA.InvI;
m_invIB = BodyB.InvI;
FVector2 cA = data.positions[m_indexA].c;
float aA = data.positions[m_indexA].a;
FVector2 vA = data.velocities[m_indexA].v;
float wA = data.velocities[m_indexA].w;
FVector2 cB = data.positions[m_indexB].c;
float aB = data.positions[m_indexB].a;
FVector2 vB = data.velocities[m_indexB].v;
float wB = data.velocities[m_indexB].w;
Rot qA = new Rot(aA), qB = new Rot(aB);
m_rA = MathUtils.Mul(qA, LocalAnchorA - m_localCenterA);
m_rB = MathUtils.Mul(qB, LocalAnchorB - m_localCenterB);
// Get the pulley axes.
m_uA = cA + m_rA - GroundAnchorA;
m_uB = cB + m_rB - GroundAnchorB;
float lengthA = m_uA.Length();
float lengthB = m_uB.Length();
if (lengthA > 10.0f * Settings.LinearSlop)
{
m_uA *= 1.0f / lengthA;
}
else
{
m_uA = FVector2.Zero;
}
if (lengthB > 10.0f * Settings.LinearSlop)
{
m_uB *= 1.0f / lengthB;
}
else
{
m_uB = FVector2.Zero;
}
// Compute effective mass.
float ruA = MathUtils.Cross(m_rA, m_uA);
float ruB = MathUtils.Cross(m_rB, m_uB);
float mA = m_invMassA + m_invIA * ruA * ruA;
float mB = m_invMassB + m_invIB * ruB * ruB;
m_mass = mA + Ratio * Ratio * mB;
if (m_mass > 0.0f)
{
m_mass = 1.0f / m_mass;
}
if (Settings.EnableWarmstarting)
{
// Scale impulses to support variable time steps.
_impulse *= data.step.dtRatio;
// Warm starting.
FVector2 PA = -(_impulse + _limitImpulse1) * m_uA;
FVector2 PB = (-Ratio * _impulse - _limitImpulse2) * m_uB;
vA += m_invMassA * PA;
wA += m_invIA * MathUtils.Cross(m_rA, PA);
vB += m_invMassB * PB;
wB += m_invIB * MathUtils.Cross(m_rB, PB);
}
else
{
_impulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
internal override void InitVelocityConstraints(ref SolverData data)
{
_indexA = BodyA.IslandIndex;
_indexB = BodyB.IslandIndex;
_localCenterA = BodyA.Sweep.LocalCenter;
_localCenterB = BodyB.Sweep.LocalCenter;
_invMassA = BodyA.InvMass;
_invMassB = BodyB.InvMass;
_invIA = BodyA.InvI;
_invIB = BodyB.InvI;
FVector2 cA = data.positions[_indexA].c;
float aA = data.positions[_indexA].a;
FVector2 vA = data.velocities[_indexA].v;
float wA = data.velocities[_indexA].w;
FVector2 cB = data.positions[_indexB].c;
float aB = data.positions[_indexB].a;
FVector2 vB = data.velocities[_indexB].v;
float wB = data.velocities[_indexB].w;
Rot qA = new Rot(aA), qB = new Rot(aB);
_rA = MathUtils.Mul(qA, LocalAnchorA - _localCenterA);
_rB = MathUtils.Mul(qB, LocalAnchorB - _localCenterB);
_u = cB + _rB - cA - _rA;
_length = _u.Length();
float C = _length - MaxLength;
if (C > 0.0f)
{
_state = LimitState.AtUpper;
}
else
{
_state = LimitState.Inactive;
}
if (_length > FSSettings.LinearSlop)
{
_u *= 1.0f / _length;
}
else
{
_u = FVector2.Zero;
_mass = 0.0f;
_impulse = 0.0f;
return;
}
// Compute effective mass.
float crA = MathUtils.Cross(_rA, _u);
float crB = MathUtils.Cross(_rB, _u);
float invMass = _invMassA + _invIA * crA * crA + _invMassB + _invIB * crB * crB;
_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
if (FSSettings.EnableWarmstarting)
{
// Scale the impulse to support a variable time step.
_impulse *= data.step.dtRatio;
FVector2 P = _impulse * _u;
vA -= _invMassA * P;
wA -= _invIA * MathUtils.Cross(_rA, P);
vB += _invMassB * P;
wB += _invIB * MathUtils.Cross(_rB, P);
}
else
{
_impulse = 0.0f;
}
data.velocities[_indexA].v = vA;
data.velocities[_indexA].w = wA;
data.velocities[_indexB].v = vB;
data.velocities[_indexB].w = wB;
}
internal void SolveTOI(ref FSTimeStep subStep, int toiIndexA, int toiIndexB)
{
Debug.Assert(toiIndexA < BodyCount);
Debug.Assert(toiIndexB < BodyCount);
// Initialize the body state.
for (int i = 0; i < BodyCount; ++i)
{
FSBody b = Bodies[i];
_positions[i].c = b.Sweep.C;
_positions[i].a = b.Sweep.A;
_velocities[i].v = b.LinearVelocity;
_velocities[i].w = b.AngularVelocity;
}
//b2ContactSolverDef contactSolverDef;
//contactSolverDef.contacts = _contacts;
//contactSolverDef.count = _contactCount;
//contactSolverDef.allocator = _allocator;
//contactSolverDef.step = subStep;
//contactSolverDef.positions = _positions;
//contactSolverDef.velocities = _velocities;
//b2ContactSolver contactSolver(&contactSolverDef);
_contactSolver.Reset(subStep, ContactCount, _contacts, _positions, _velocities);
// Solve position constraints.
for (int i = 0; i < FSSettings.TOIPositionIterations; ++i)
{
bool contactsOkay = _contactSolver.SolveTOIPositionConstraints(toiIndexA, toiIndexB);
if (contactsOkay)
{
break;
}
}
// Leap of faith to new safe state.
Bodies[toiIndexA].Sweep.C0 = _positions[toiIndexA].c;
Bodies[toiIndexA].Sweep.A0 = _positions[toiIndexA].a;
Bodies[toiIndexB].Sweep.C0 = _positions[toiIndexB].c;
Bodies[toiIndexB].Sweep.A0 = _positions[toiIndexB].a;
// No warm starting is needed for TOI events because warm
// starting impulses were applied in the discrete solver.
_contactSolver.InitializeVelocityConstraints();
// Solve velocity constraints.
for (int i = 0; i < FSSettings.TOIVelocityIterations; ++i)
{
_contactSolver.SolveVelocityConstraints();
}
// Don't store the TOI contact forces for warm starting
// because they can be quite large.
float h = subStep.dt;
// Integrate positions.
for (int i = 0; i < BodyCount; ++i)
{
FVector2 c = _positions[i].c;
float a = _positions[i].a;
FVector2 v = _velocities[i].v;
float w = _velocities[i].w;
// Check for large velocities
FVector2 translation = h * v;
if (FVector2.Dot(translation, translation) > FSSettings.MaxTranslationSquared)
{
float ratio = FSSettings.MaxTranslation / translation.Length();
v *= ratio;
}
float rotation = h * w;
if (rotation * rotation > FSSettings.MaxRotationSquared)
{
float ratio = FSSettings.MaxRotation / Math.Abs(rotation);
w *= ratio;
}
// Integrate
c += h * v;
a += h * w;
_positions[i].c = c;
_positions[i].a = a;
_velocities[i].v = v;
_velocities[i].w = w;
// Sync bodies
FSBody body = Bodies[i];
body.Sweep.C = c;
body.Sweep.A = a;
body.LinearVelocity = v;
body.AngularVelocity = w;
body.SynchronizeTransform();
}
Report(_contactSolver._velocityConstraints);
}
internal override void InitVelocityConstraints(ref SolverData data)
{
m_indexA = BodyA.IslandIndex;
m_indexB = BodyB.IslandIndex;
m_localCenterA = BodyA.Sweep.LocalCenter;
m_localCenterB = BodyB.Sweep.LocalCenter;
m_invMassA = BodyA.InvMass;
m_invMassB = BodyB.InvMass;
m_invIA = BodyA.InvI;
m_invIB = BodyB.InvI;
FVector2 cA = data.positions[m_indexA].c;
float aA = data.positions[m_indexA].a;
FVector2 vA = data.velocities[m_indexA].v;
float wA = data.velocities[m_indexA].w;
FVector2 cB = data.positions[m_indexB].c;
float aB = data.positions[m_indexB].a;
FVector2 vB = data.velocities[m_indexB].v;
float wB = data.velocities[m_indexB].w;
Rot qA = new Rot(aA), qB = new Rot(aB);
m_rA = MathUtils.Mul(qA, LocalAnchorA - m_localCenterA);
m_rB = MathUtils.Mul(qB, LocalAnchorB - m_localCenterB);
_u = cB + m_rB - cA - m_rA;
// Handle singularity.
float length = _u.Length();
if (length > Settings.LinearSlop)
{
_u *= 1.0f / length;
}
else
{
_u = FVector2.Zero;
}
float crAu = MathUtils.Cross(m_rA, _u);
float crBu = MathUtils.Cross(m_rB, _u);
float invMass = m_invMassA + m_invIA * crAu * crAu + m_invMassB + m_invIB * crBu * crBu;
// Compute the effective mass matrix.
_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
if (Frequency > 0.0f)
{
float C = length - Length;
// Frequency
float omega = 2.0f * Settings.Pi * Frequency;
// Damping coefficient
float d = 2.0f * _mass * DampingRatio * omega;
// Spring stiffness
float k = _mass * omega * omega;
// magic formulas
float h = data.step.dt;
_gamma = h * (d + h * k);
_gamma = _gamma != 0.0f ? 1.0f / _gamma : 0.0f;
_bias = C * h * k * _gamma;
invMass += _gamma;
_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
}
else
{
_gamma = 0.0f;
_bias = 0.0f;
}
if (Settings.EnableWarmstarting)
{
// Scale the impulse to support a variable time step.
_impulse *= data.step.dtRatio;
FVector2 P = _impulse * _u;
vA -= m_invMassA * P;
wA -= m_invIA * MathUtils.Cross(m_rA, P);
vB += m_invMassB * P;
wB += m_invIB * MathUtils.Cross(m_rB, P);
}
else
{
_impulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
internal override void InitVelocityConstraints(ref SolverData data)
{
FSBody b1 = BodyA;
FSBody b2 = BodyB;
Transform xf1, xf2;
b1.GetTransform(out xf1);
b2.GetTransform(out xf2);
// Compute the effective mass matrix.
FVector2 r1 = MathUtils.Mul(ref xf1.q, LocalAnchorA - b1.LocalCenter);
FVector2 r2 = MathUtils.Mul(ref xf2.q, LocalAnchorB - b2.LocalCenter);
_u = b2.Sweep.C + r2 - b1.Sweep.C - r1;
// Handle singularity.
float length = _u.Length();
if (length < MaxLength && length > MinLength)
{
return;
}
if (length > FSSettings.LinearSlop)
{
_u *= 1.0f / length;
}
else
{
_u = FVector2.Zero;
}
float cr1u = MathUtils.Cross(r1, _u);
float cr2u = MathUtils.Cross(r2, _u);
float invMass = b1.InvMass + b1.InvI * cr1u * cr1u + b2.InvMass + b2.InvI * cr2u * cr2u;
Debug.Assert(invMass > FSSettings.Epsilon);
_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
if (Frequency > 0.0f)
{
float C = length - MaxLength;
// Frequency
float omega = 2.0f * FSSettings.Pi * Frequency;
// Damping coefficient
float d = 2.0f * _mass * DampingRatio * omega;
// Spring stiffness
float k = _mass * omega * omega;
// magic formulas
_gamma = data.step.dt * (d + data.step.dt * k);
_gamma = _gamma != 0.0f ? 1.0f / _gamma : 0.0f;
_bias = C * data.step.dt * k * _gamma;
_mass = invMass + _gamma;
_mass = _mass != 0.0f ? 1.0f / _mass : 0.0f;
}
if (FSSettings.EnableWarmstarting)
{
// Scale the impulse to support a variable time step.
_impulse *= data.step.dtRatio;
FVector2 P = _impulse * _u;
b1.LinearVelocityInternal -= b1.InvMass * P;
b1.AngularVelocityInternal -= b1.InvI * MathUtils.Cross(r1, P);
b2.LinearVelocityInternal += b2.InvMass * P;
b2.AngularVelocityInternal += b2.InvI * MathUtils.Cross(r2, P);
}
else
{
_impulse = 0.0f;
}
}
public void Solve(ref FSTimeStep step, ref FVector2 gravity)
{
float h = step.dt;
// Integrate velocities and apply damping. Initialize the body state.
for (int i = 0; i < BodyCount; ++i)
{
FSBody b = Bodies[i];
FVector2 c = b.Sweep.C;
float a = b.Sweep.A;
FVector2 v = b.LinearVelocity;
float w = b.AngularVelocity;
// Store positions for continuous collision.
b.Sweep.C0 = b.Sweep.C;
b.Sweep.A0 = b.Sweep.A;
if (b.BodyType == BodyType.Dynamic)
{
// Integrate velocities.
v += h * (b.GravityScale * gravity + b.InvMass * b.Force);
w += h * 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
v *= MathUtils.Clamp(1.0f - h * b.LinearDamping, 0.0f, 1.0f);
w *= MathUtils.Clamp(1.0f - h * b.AngularDamping, 0.0f, 1.0f);
}
_positions[i].c = c;
_positions[i].a = a;
_velocities[i].v = v;
_velocities[i].w = w;
}
// Solver data
SolverData solverData = new SolverData();
solverData.step = step;
solverData.positions = _positions;
solverData.velocities = _velocities;
// Initialize velocity constraints.
//b2ContactSolverDef contactSolverDef;
//contactSolverDef.step = step;
//contactSolverDef.contacts = m_contacts;
//contactSolverDef.count = m_contactCount;
//contactSolverDef.positions = m_positions;
//contactSolverDef.velocities = m_velocities;
//contactSolverDef.allocator = m_allocator;
_contactSolver.Reset(step, ContactCount, _contacts, _positions, _velocities);
_contactSolver.InitializeVelocityConstraints();
if (FSSettings.EnableWarmstarting)
{
_contactSolver.WarmStart();
}
#if (!SILVERLIGHT)
if (FSSettings.EnableDiagnostics)
{
_watch.Start();
_tmpTime = 0;
}
#endif
for (int i = 0; i < JointCount; ++i)
{
if (_joints[i].Enabled)
{
_joints[i].InitVelocityConstraints(ref solverData);
}
}
#if (!SILVERLIGHT)
if (FSSettings.EnableDiagnostics)
{
_tmpTime += _watch.ElapsedTicks;
}
#endif
// Solve velocity constraints.
for (int i = 0; i < FSSettings.VelocityIterations; ++i)
{
#if (!SILVERLIGHT)
if (FSSettings.EnableDiagnostics)
{
_watch.Start();
}
#endif
for (int j = 0; j < JointCount; ++j)
{
FarseerJoint joint = _joints[j];
if (!joint.Enabled)
{
continue;
}
joint.SolveVelocityConstraints(ref solverData);
//TODO: Move up before solve?
joint.Validate(step.inv_dt);
}
#if (!SILVERLIGHT)
if (FSSettings.EnableDiagnostics)
{
_watch.Stop();
_tmpTime += _watch.ElapsedTicks;
_watch.Reset();
}
#endif
_contactSolver.SolveVelocityConstraints();
}
// Store impulses for warm starting.
_contactSolver.StoreImpulses();
// Integrate positions
for (int i = 0; i < BodyCount; ++i)
{
FVector2 c = _positions[i].c;
float a = _positions[i].a;
FVector2 v = _velocities[i].v;
float w = _velocities[i].w;
// Check for large velocities
FVector2 translation = h * v;
if (FVector2.Dot(translation, translation) > FSSettings.MaxTranslationSquared)
{
float ratio = FSSettings.MaxTranslation / translation.Length();
v *= ratio;
}
float rotation = h * w;
if (rotation * rotation > FSSettings.MaxRotationSquared)
{
float ratio = FSSettings.MaxRotation / Math.Abs(rotation);
w *= ratio;
}
// Integrate
c += h * v;
a += h * w;
_positions[i].c = c;
_positions[i].a = a;
_velocities[i].v = v;
_velocities[i].w = w;
}
// Solve position constraints
bool positionSolved = false;
for (int i = 0; i < FSSettings.PositionIterations; ++i)
{
bool contactsOkay = _contactSolver.SolvePositionConstraints();
bool jointsOkay = true;
#if (!SILVERLIGHT)
if (FSSettings.EnableDiagnostics)
{
_watch.Start();
}
#endif
for (int j = 0; j < JointCount; ++j)
{
FarseerJoint joint = _joints[j];
if (!joint.Enabled)
{
continue;
}
bool jointOkay = joint.SolvePositionConstraints(ref solverData);
jointsOkay = jointsOkay && jointOkay;
}
#if (!SILVERLIGHT)
if (FSSettings.EnableDiagnostics)
{
_watch.Stop();
_tmpTime += _watch.ElapsedTicks;
_watch.Reset();
}
#endif
if (contactsOkay && jointsOkay)
{
// Exit early if the position errors are small.
positionSolved = true;
break;
}
}
#if (!SILVERLIGHT)
if (FSSettings.EnableDiagnostics)
{
JointUpdateTime = _tmpTime;
}
#endif
// Copy state buffers back to the bodies
for (int i = 0; i < BodyCount; ++i)
{
FSBody body = Bodies[i];
body.Sweep.C = _positions[i].c;
body.Sweep.A = _positions[i].a;
body.LinearVelocity = _velocities[i].v;
body.AngularVelocity = _velocities[i].w;
body.SynchronizeTransform();
}
Report(_contactSolver._velocityConstraints);
if (FSSettings.AllowSleep)
{
float minSleepTime = FSSettings.MaxFloat;
for (int i = 0; i < BodyCount; ++i)
{
FSBody b = Bodies[i];
if (b.BodyType == BodyType.Static)
{
continue;
}
if ((b.Flags & BodyFlags.AutoSleep) == 0 ||
b.AngularVelocityInternal * b.AngularVelocityInternal > AngTolSqr ||
FVector2.Dot(b.LinearVelocityInternal, b.LinearVelocityInternal) > LinTolSqr)
{
b.SleepTime = 0.0f;
minSleepTime = 0.0f;
}
else
{
b.SleepTime += h;
minSleepTime = Math.Min(minSleepTime, b.SleepTime);
}
}
if (minSleepTime >= FSSettings.TimeToSleep && positionSolved)
{
for (int i = 0; i < BodyCount; ++i)
{
FSBody b = Bodies[i];
b.Awake = false;
}
}
}
}
public override void Update(float dt)
{
FVector2 f = FVector2.Zero;
foreach (FSBody body1 in World.BodyList)
{
if (!IsActiveOn(body1))
{
continue;
}
foreach (FSBody body2 in Bodies)
{
if (body1 == body2 || (body1.IsStatic && body2.IsStatic) || !body2.Enabled)
{
continue;
}
FVector2 d = body2.WorldCenter - body1.WorldCenter;
float r2 = d.LengthSquared();
if (r2 < FSSettings.Epsilon)
{
continue;
}
float r = d.Length();
if (r >= MaxRadius || r <= MinRadius)
{
continue;
}
switch (GravityType)
{
case GravityType.DistanceSquared:
f = Strength / r2 / (float)Math.Sqrt(r2) * body1.Mass * body2.Mass * d;
break;
case GravityType.Linear:
f = Strength / r2 * body1.Mass * body2.Mass * d;
break;
}
body1.ApplyForce(ref f);
FVector2.Negate(ref f, out f);
body2.ApplyForce(ref f);
}
foreach (FVector2 point in Points)
{
FVector2 d = point - body1.Position;
float r2 = d.LengthSquared();
if (r2 < FSSettings.Epsilon)
{
continue;
}
float r = d.Length();
if (r >= MaxRadius || r <= MinRadius)
{
continue;
}
switch (GravityType)
{
case GravityType.DistanceSquared:
f = Strength / r2 / (float)Math.Sqrt(r2) * body1.Mass * d;
break;
case GravityType.Linear:
f = Strength / r2 * body1.Mass * d;
break;
}
body1.ApplyForce(ref f);
}
}
}
