public void Prestep(float inverseDt) { //Given that we're collecting position, inverse mass, and inertia all at once, it makes no sense to store position separately from inversemass and inertia. //Since you should not expect the 4 involved bodies to be in memory *together*, the best you can do is to ensure that the set of values are together. //Otherwise you're multiplying cache misses for no reason! var inverseMassA = new Vector4(BodyA0.InverseMass, BodyA1.InverseMass, BodyA2.InverseMass, BodyA3.InverseMass); var inverseMassB = new Vector4(BodyB0.InverseMass, BodyB1.InverseMass, BodyB2.InverseMass, BodyB3.InverseMass); var inverseInertiaTensorA = new Matrix3x3Width4(ref BodyA0.InertiaTensorInverse, ref BodyA1.InertiaTensorInverse, ref BodyA2.InertiaTensorInverse, ref BodyA3.InertiaTensorInverse); var inverseInertiaTensorB = new Matrix3x3Width4(ref BodyB0.InertiaTensorInverse, ref BodyB1.InertiaTensorInverse, ref BodyB2.InertiaTensorInverse, ref BodyB3.InertiaTensorInverse); Vector3Width4 positionA = new Vector3Width4(ref BodyA0.Position, ref BodyA1.Position, ref BodyA2.Position, ref BodyA3.Position); Vector3Width4 positionB = new Vector3Width4(ref BodyA0.Position, ref BodyB1.Position, ref BodyB2.Position, ref BodyB3.Position); for (int i = 0; i < ConstraintCount; ++i) { Constraints[i].Prestep(inverseDt, ref inverseMassA, ref inverseMassB, ref inverseInertiaTensorA, ref inverseInertiaTensorB, ref positionA, ref positionB); } //for (int i = 0; i < 4; ++i) //{ // a.Prestep(inverseDt, ref InverseMassA, ref InverseMassB, ref InverseInertiaTensorA, ref InverseInertiaTensorB, ref positionA, ref positionB); //} //a.Prestep(inverseDt, ref InverseMassA, ref InverseMassB, ref InverseInertiaTensorA, ref InverseInertiaTensorB, ref positionA, ref positionB); //b.Prestep(inverseDt, ref InverseMassA, ref InverseMassB, ref InverseInertiaTensorA, ref InverseInertiaTensorB, ref positionA, ref positionB); //c.Prestep(inverseDt, ref InverseMassA, ref InverseMassB, ref InverseInertiaTensorA, ref InverseInertiaTensorB, ref positionA, ref positionB); //d.Prestep(inverseDt, ref InverseMassA, ref InverseMassB, ref InverseInertiaTensorA, ref InverseInertiaTensorB, ref positionA, ref positionB); }
public void Prestep(float inverseDt) { //C = dot(Pa - Pb, N) > 0 //Jacobians: //LinearA: N //AngularA: cross(OffsetPa, N) //LinearB: -N //AngularB: -cross(OffsetPb, N) //var positionA = new Vector3Width4(); //var positionB = new Vector3Width4(); //Given that we're collecting position, inverse mass, and inertia all at once, it makes no sense to store position separately from inversemass and inertia. //Since you should not expect the 4 involved bodies to be in memory *together*, the best you can do is to ensure that the set of values are together. //Otherwise you're multiplying cache misses for no reason! var InverseMassA = new Vector4(BodyA0.InverseMass, BodyA1.InverseMass, BodyA2.InverseMass, BodyA3.InverseMass); var InverseMassB = new Vector4(BodyB0.InverseMass, BodyB1.InverseMass, BodyB2.InverseMass, BodyB3.InverseMass); var InverseInertiaTensorA = new Matrix3x3Width4(ref BodyA0.InertiaTensorInverse, ref BodyA1.InertiaTensorInverse, ref BodyA2.InertiaTensorInverse, ref BodyA3.InertiaTensorInverse); var InverseInertiaTensorB = new Matrix3x3Width4(ref BodyB0.InertiaTensorInverse, ref BodyB1.InertiaTensorInverse, ref BodyB2.InertiaTensorInverse, ref BodyB3.InertiaTensorInverse); Vector3Width4 positionA = new Vector3Width4(ref BodyA0.Position, ref BodyA1.Position, ref BodyA2.Position, ref BodyA3.Position); Vector3Width4 positionB = new Vector3Width4(ref BodyA0.Position, ref BodyB1.Position, ref BodyB2.Position, ref BodyB3.Position); LinearJacobianA = ContactNormal; Vector3Width4.Negate(ref ContactNormal, out LinearJacobianB); Vector3Width4 offsetA, offsetB; Vector3Width4.Subtract(ref ContactPosition, ref positionA, out offsetA); Vector3Width4.Subtract(ref ContactPosition, ref positionB, out offsetB); Vector3Width4.Cross(ref offsetA, ref ContactNormal, out AngularJacobianA); Vector3Width4.Cross(ref ContactNormal, ref offsetB, out AngularJacobianB);// note negation->parameter reverse //Allow velocity that closes a gap, and apply penetration correction against positive depth. //Bounciness not yet included. PenetrationBias = ContactPenetration * inverseDt; PenetrationBias = -Vector4.Min(Vector4.Min(PenetrationBias, PenetrationBias * 0.2f), new Vector4(0.2f)); //The inertia tensor is in world space, so no jacobian transformation is required. Vector3Width4.Multiply(ref LinearJacobianA, ref InverseMassA, out LinearJacobianITA); Vector3Width4.Multiply(ref LinearJacobianB, ref InverseMassB, out LinearJacobianITB); Matrix3x3Width4.Transform(ref AngularJacobianA, ref InverseInertiaTensorA, out AngularJacobianITA); Matrix3x3Width4.Transform(ref AngularJacobianB, ref InverseInertiaTensorB, out AngularJacobianITB); Vector4 angularContributionA, angularContributionB; Vector3Width4.Dot(ref AngularJacobianITA, ref AngularJacobianITA, out angularContributionA); Vector3Width4.Dot(ref AngularJacobianITB, ref AngularJacobianITB, out angularContributionB); var inverseEffectiveMass = InverseMassA + InverseMassB + angularContributionA + angularContributionB; Vector4 CollisionSoftness = new Vector4(5); Softness = CollisionSoftness * inverseEffectiveMass * inverseDt; EffectiveMass = Vector4.One / (Softness + inverseEffectiveMass); }
public void Prestep(float inverseDt, ref Vector4 inverseMassA, ref Vector4 inverseMassB, ref Matrix3x3Width4 inverseInertiaTensorA, ref Matrix3x3Width4 inverseInertiaTensorB, ref Vector3Width4 positionA, ref Vector3Width4 positionB) { //C = dot(Pa - Pb, N) > 0 //Jacobians: //LinearA: N //AngularA: cross(OffsetPa, N) //LinearB: -N //AngularB: -cross(OffsetPb, N) //var positionA = new Vector3Width4(); //var positionB = new Vector3Width4(); LinearJacobianA = ContactNormal; Vector3Width4.Negate(ref ContactNormal, out LinearJacobianB); Vector3Width4 offsetA, offsetB; Vector3Width4.Subtract(ref ContactPosition, ref positionA, out offsetA); Vector3Width4.Subtract(ref ContactPosition, ref positionB, out offsetB); Vector3Width4.Cross(ref offsetA, ref ContactNormal, out AngularJacobianA); Vector3Width4.Cross(ref ContactNormal, ref offsetB, out AngularJacobianB);// note negation->parameter reverse //Allow velocity that closes a gap, and apply penetration correction against positive depth. //Bounciness not yet included. PenetrationBias = ContactPenetration * inverseDt; PenetrationBias = -Vector4.Min(Vector4.Min(PenetrationBias, PenetrationBias * 0.2f), new Vector4(0.2f)); //The inertia tensor is in world space, so no jacobian transformation is required. Vector3Width4.Multiply(ref LinearJacobianA, ref inverseMassA, out LinearJacobianITA); Vector3Width4.Multiply(ref LinearJacobianB, ref inverseMassB, out LinearJacobianITB); Matrix3x3Width4.Transform(ref AngularJacobianA, ref inverseInertiaTensorA, out AngularJacobianITA); Matrix3x3Width4.Transform(ref AngularJacobianB, ref inverseInertiaTensorB, out AngularJacobianITB); Vector4 angularContributionA, angularContributionB; Vector3Width4.Dot(ref AngularJacobianITA, ref AngularJacobianITA, out angularContributionA); Vector3Width4.Dot(ref AngularJacobianITB, ref AngularJacobianITB, out angularContributionB); var inverseEffectiveMass = inverseMassA + inverseMassB + angularContributionA + angularContributionB; Vector4 CollisionSoftness = new Vector4(5); Softness = CollisionSoftness * inverseEffectiveMass * inverseDt; EffectiveMass = Vector4.One / (Softness + inverseEffectiveMass); }
public static void Transform(ref Vector3Width4 v, ref Matrix3x3Width4 m, out Vector3Width4 result) { result.X = v.X * m.M11 + v.Y * m.M21 + v.Z * m.M31; result.Y = v.X * m.M12 + v.Y * m.M22 + v.Z * m.M32; result.Z = v.X * m.M13 + v.Y * m.M23 + v.Z * m.M33; }