public static void Prestep(ref BodyInertias inertiaA, ref Vector3Wide normal, ref Contact1OneBodyPrestepData prestep, float dt, float inverseDt,
out Projection projection)
{
Vector3Wide.CrossWithoutOverlap(ref prestep.OffsetA0, ref normal, out projection.Penetration0.AngularA);
//effective mass
Triangular3x3Wide.VectorSandwich(ref projection.Penetration0.AngularA, ref inertiaA.InverseInertiaTensor, out var angularA0);
//Linear effective mass contribution notes:
//1) The J * M^-1 * JT can be reordered to J * JT * M^-1 for the linear components, since M^-1 is a scalar and dot(n * scalar, n) = dot(n, n) * scalar.
//2) dot(normal, normal) == 1, so the contribution from each body is just its inverse mass.
Springiness.ComputeSpringiness(ref prestep.SpringSettings, dt, 4f, out var positionErrorToVelocity, out var effectiveMassCFMScale, out projection.SoftnessImpulseScale);
//Note that we don't precompute the JT * effectiveMass term. Since the jacobians are shared, we have to do that multiply anyway.
projection.Penetration0.EffectiveMass = effectiveMassCFMScale / (inertiaA.InverseMass + angularA0);
//If depth is negative, the bias velocity will permit motion up until the depth hits zero. This works because positionErrorToVelocity * dt will always be <=1.
projection.Penetration0.BiasVelocity = Vector.Min(
prestep.PenetrationDepth0 * new Vector <float>(inverseDt),
Vector.Min(prestep.PenetrationDepth0 * positionErrorToVelocity, prestep.MaximumRecoveryVelocity));
}
public static void Prestep(ref BodyInertias inertiaA, ref Contact1OneBodyPrestepData prestep, float dt, float inverseDt,
out Projection projection)
{
Prestep(ref inertiaA, ref prestep.OffsetA0, ref prestep.Normal, ref prestep.PenetrationDepth0, ref prestep.SpringSettings, ref prestep.MaximumRecoveryVelocity, dt, inverseDt, out projection);
}
