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Attenuate the warmstart impulse for CCD contacts.

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CCD contacts result in very strong, instantaneous, impulses. So it is preferable to attenuate their contribution to subsequent timesteps to avoid overshooting.
This commit is contained in:
Crozet Sébastien
2021-03-28 11:26:53 +02:00
parent 710dd8d71e
commit 7306821c46
10 changed files with 114 additions and 62 deletions
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16
src/dynamics/solver/velocity_ground_constraint.rs
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@@ -133,6 +133,7 @@ impl VelocityGroundConstraint {
let dp1 = manifold_point.point - rb1.world_com;
let vel1 = rb1.linvel + rb1.angvel.gcross(dp1);
let vel2 = rb2.linvel + rb2.angvel.gcross(dp2);
let warmstart_correction;
constraint.limit = manifold_point.friction;
constraint.manifold_contact_id[k] = manifold_point.contact_id;
@@ -153,11 +154,14 @@ impl VelocityGroundConstraint {
rhs += manifold_point.dist.max(0.0) * inv_dt;
rhs *= is_bouncy + is_resting * params.velocity_solve_fraction;
rhs += is_resting * velocity_based_erp_inv_dt * manifold_point.dist.min(0.0);
warmstart_correction = (params.warmstart_correction_slope
/ (rhs - manifold_point.prev_rhs).abs())
.min(warmstart_coeff);
constraint.elements[k].normal_part = VelocityGroundConstraintNormalPart {
gcross2,
rhs,
impulse: manifold_point.data.impulse * warmstart_coeff,
impulse: manifold_point.warmstart_impulse * warmstart_correction,
r,
};
}
@@ -165,10 +169,12 @@ impl VelocityGroundConstraint {
// Tangent parts.
{
#[cfg(feature = "dim3")]
let impulse =
tangent_rot1 * manifold_points[k].data.tangent_impulse * warmstart_coeff;
let impulse = tangent_rot1
* manifold_points[k].warmstart_tangent_impulse
* warmstart_correction;
#[cfg(feature = "dim2")]
let impulse = [manifold_points[k].data.tangent_impulse * warmstart_coeff];
let impulse =
[manifold_points[k].warmstart_tangent_impulse * warmstart_correction];
constraint.elements[k].tangent_part.impulse = impulse;
for j in 0..DIM - 1 {
@@ -237,6 +243,8 @@ impl VelocityGroundConstraint {
let contact_id = self.manifold_contact_id[k];
let active_contact = &mut manifold.points[contact_id as usize];
active_contact.data.impulse = self.elements[k].normal_part.impulse;
active_contact.data.rhs = self.elements[k].normal_part.rhs;
#[cfg(feature = "dim2")]
{
active_contact.data.tangent_impulse = self.elements[k].tangent_part.impulse[0];