protected internal override int FindOverlappingTriangles(float dt)
{
BoundingBox boundingBox;
convex.Shape.GetLocalBoundingBox(ref convex.worldTransform, ref terrain.worldTransform, out boundingBox);
if (convex.entity != null)
{
Vector3 transformedVelocity;
Matrix3x3 inverse;
Matrix3x3.Invert(ref terrain.worldTransform.LinearTransform, out inverse);
Matrix3x3.Transform(ref convex.entity.linearVelocity, ref inverse, out transformedVelocity);
Vector3.Multiply(ref transformedVelocity, dt, out transformedVelocity);
if (transformedVelocity.X > 0)
{
boundingBox.Max.X += transformedVelocity.X;
}
else
{
boundingBox.Min.X += transformedVelocity.X;
}
if (transformedVelocity.Y > 0)
{
boundingBox.Max.Y += transformedVelocity.Y;
}
else
{
boundingBox.Min.Y += transformedVelocity.Y;
}
if (transformedVelocity.Z > 0)
{
boundingBox.Max.Z += transformedVelocity.Z;
}
else
{
boundingBox.Min.Z += transformedVelocity.Z;
}
}
terrain.Shape.GetOverlaps(boundingBox, ref overlappedTriangles);
return(overlappedTriangles.Count);
}
/// <summary>
/// Calculates necessary information for velocity solving.
/// Called by preStep(float dt)
/// </summary>
/// <param name="dt">Time in seconds since the last update.</param>
public override void Update(float dt)
{
Matrix3x3.Transform(ref localAnchorA, ref connectionA.orientationMatrix, out worldOffsetA);
Matrix3x3.Transform(ref localAnchorB, ref connectionB.orientationMatrix, out worldOffsetB);
float errorReductionParameter;
springSettings.ComputeErrorReductionAndSoftness(dt, 1 / dt, out errorReductionParameter, out softness);
//Mass Matrix
Matrix3x3 k;
Matrix3x3 linearComponent;
Matrix3x3.CreateCrossProduct(ref worldOffsetA, out rACrossProduct);
Matrix3x3.CreateCrossProduct(ref worldOffsetB, out rBCrossProduct);
if (connectionA.isDynamic && connectionB.isDynamic)
{
Matrix3x3.CreateScale(connectionA.inverseMass + connectionB.inverseMass, out linearComponent);
Matrix3x3 angularComponentA, angularComponentB;
Matrix3x3.Multiply(ref rACrossProduct, ref connectionA.inertiaTensorInverse, out angularComponentA);
Matrix3x3.Multiply(ref rBCrossProduct, ref connectionB.inertiaTensorInverse, out angularComponentB);
Matrix3x3.Multiply(ref angularComponentA, ref rACrossProduct, out angularComponentA);
Matrix3x3.Multiply(ref angularComponentB, ref rBCrossProduct, out angularComponentB);
Matrix3x3.Subtract(ref linearComponent, ref angularComponentA, out k);
Matrix3x3.Subtract(ref k, ref angularComponentB, out k);
}
else if (connectionA.isDynamic && !connectionB.isDynamic)
{
Matrix3x3.CreateScale(connectionA.inverseMass, out linearComponent);
Matrix3x3 angularComponentA;
Matrix3x3.Multiply(ref rACrossProduct, ref connectionA.inertiaTensorInverse, out angularComponentA);
Matrix3x3.Multiply(ref angularComponentA, ref rACrossProduct, out angularComponentA);
Matrix3x3.Subtract(ref linearComponent, ref angularComponentA, out k);
}
else if (!connectionA.isDynamic && connectionB.isDynamic)
{
Matrix3x3.CreateScale(connectionB.inverseMass, out linearComponent);
Matrix3x3 angularComponentB;
Matrix3x3.Multiply(ref rBCrossProduct, ref connectionB.inertiaTensorInverse, out angularComponentB);
Matrix3x3.Multiply(ref angularComponentB, ref rBCrossProduct, out angularComponentB);
Matrix3x3.Subtract(ref linearComponent, ref angularComponentB, out k);
}
else
{
throw new InvalidOperationException("Cannot constrain two kinematic bodies.");
}
k.M11 += softness;
k.M22 += softness;
k.M33 += softness;
Matrix3x3.Invert(ref k, out massMatrix);
Vector3.Add(ref connectionB.position, ref worldOffsetB, out error);
Vector3.Subtract(ref error, ref connectionA.position, out error);
Vector3.Subtract(ref error, ref worldOffsetA, out error);
Vector3.Multiply(ref error, -errorReductionParameter, out biasVelocity);
//Ensure that the corrective velocity doesn't exceed the max.
float length = biasVelocity.LengthSquared();
if (length > maxCorrectiveVelocitySquared)
{
float multiplier = maxCorrectiveVelocity / (float)Math.Sqrt(length);
biasVelocity.X *= multiplier;
biasVelocity.Y *= multiplier;
biasVelocity.Z *= multiplier;
}
}
/// <summary>
/// Initializes the constraint for the current frame.
/// </summary>
/// <param name="dt">Time between frames.</param>
public override void Update(float dt)
{
basis.rotationMatrix = entity.orientationMatrix;
basis.ComputeWorldSpaceAxes();
float updateRate = 1 / dt;
if (settings.mode == MotorMode.Servomechanism) //Only need to do the bulk of this work if it's a servo.
{
Quaternion currentRelativeOrientation;
var worldTransform = basis.WorldTransform;
Quaternion.CreateFromRotationMatrix(ref worldTransform, out currentRelativeOrientation);
//Compute the relative orientation R' between R and the target relative orientation.
Quaternion errorOrientation;
Quaternion.Conjugate(ref currentRelativeOrientation, out errorOrientation);
Quaternion.Multiply(ref settings.servo.goal, ref errorOrientation, out errorOrientation);
float errorReduction;
settings.servo.springSettings.ComputeErrorReductionAndSoftness(dt, updateRate, out errorReduction, out usedSoftness);
//Turn this into an axis-angle representation.
Quaternion.GetAxisAngleFromQuaternion(ref errorOrientation, out axis, out angle);
//Scale the axis by the desired velocity if the angle is sufficiently large (epsilon).
if (angle > Toolbox.BigEpsilon)
{
float velocity = MathHelper.Min(settings.servo.baseCorrectiveSpeed, angle * updateRate) + angle * errorReduction;
biasVelocity.X = axis.X * velocity;
biasVelocity.Y = axis.Y * velocity;
biasVelocity.Z = axis.Z * velocity;
//Ensure that the corrective velocity doesn't exceed the max.
float length = biasVelocity.LengthSquared();
if (length > settings.servo.maxCorrectiveVelocitySquared)
{
float multiplier = settings.servo.maxCorrectiveVelocity / (float)Math.Sqrt(length);
biasVelocity.X *= multiplier;
biasVelocity.Y *= multiplier;
biasVelocity.Z *= multiplier;
}
}
else
{
//Wouldn't want an old frame's bias velocity to sneak in.
biasVelocity = new Vector3();
}
}
else
{
usedSoftness = settings.velocityMotor.softness * updateRate;
angle = 0; //Zero out the error;
Matrix3x3 transform = basis.WorldTransform;
Matrix3x3.Transform(ref settings.velocityMotor.goalVelocity, ref transform, out biasVelocity);
}
//Compute effective mass
effectiveMassMatrix = entity.inertiaTensorInverse;
effectiveMassMatrix.M11 += usedSoftness;
effectiveMassMatrix.M22 += usedSoftness;
effectiveMassMatrix.M33 += usedSoftness;
Matrix3x3.Invert(ref effectiveMassMatrix, out effectiveMassMatrix);
//Update the maximum force
ComputeMaxForces(settings.maximumForce, dt);
}
///<summary>
/// Performs the frame's configuration step.
///</summary>
///<param name="dt">Timestep duration.</param>
public override void Update(float dt)
{
//Transform point into world space.
Matrix3x3.Transform(ref localPoint, ref entity.orientationMatrix, out r);
Vector3.Add(ref r, ref entity.position, out worldPoint);
float updateRate = 1 / dt;
if (settings.mode == MotorMode.Servomechanism)
{
Vector3.Subtract(ref settings.servo.goal, ref worldPoint, out error);
float separationDistance = error.Length();
if (separationDistance > Toolbox.BigEpsilon)
{
float errorReduction;
settings.servo.springSettings.ComputeErrorReductionAndSoftness(dt, updateRate, out errorReduction, out usedSoftness);
//The rate of correction can be based on a constant correction velocity as well as a 'spring like' correction velocity.
//The constant correction velocity could overshoot the destination, so clamp it.
float correctionSpeed = MathHelper.Min(settings.servo.baseCorrectiveSpeed, separationDistance * updateRate) +
separationDistance * errorReduction;
Vector3.Multiply(ref error, correctionSpeed / separationDistance, out biasVelocity);
//Ensure that the corrective velocity doesn't exceed the max.
float length = biasVelocity.LengthSquared();
if (length > settings.servo.maxCorrectiveVelocitySquared)
{
float multiplier = settings.servo.maxCorrectiveVelocity / (float)Math.Sqrt(length);
biasVelocity.X *= multiplier;
biasVelocity.Y *= multiplier;
biasVelocity.Z *= multiplier;
}
}
else
{
//Wouldn't want to use a bias from an earlier frame.
biasVelocity = new Vector3();
}
}
else
{
usedSoftness = settings.velocityMotor.softness * updateRate;
biasVelocity = settings.velocityMotor.goalVelocity;
error = Vector3.Zero;
}
//Compute the maximum force that can be applied this frame.
ComputeMaxForces(settings.maximumForce, dt);
//COMPUTE EFFECTIVE MASS MATRIX
//Transforms a change in velocity to a change in momentum when multiplied.
Matrix3x3 linearComponent;
Matrix3x3.CreateScale(entity.inverseMass, out linearComponent);
Matrix3x3 rACrossProduct;
Matrix3x3.CreateCrossProduct(ref r, out rACrossProduct);
Matrix3x3 angularComponentA;
Matrix3x3.Multiply(ref rACrossProduct, ref entity.inertiaTensorInverse, out angularComponentA);
Matrix3x3.Multiply(ref angularComponentA, ref rACrossProduct, out angularComponentA);
Matrix3x3.Subtract(ref linearComponent, ref angularComponentA, out effectiveMassMatrix);
effectiveMassMatrix.M11 += usedSoftness;
effectiveMassMatrix.M22 += usedSoftness;
effectiveMassMatrix.M33 += usedSoftness;
Matrix3x3.Invert(ref effectiveMassMatrix, out effectiveMassMatrix);
}