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Projection friction impulses on an implicit cone instead of a pyramidal approximation.

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This commit is contained in:
Crozet Sébastien
2021-03-07 11:43:47 +01:00
parent e7f805aea4
commit bed47a82e7
15 changed files with 618 additions and 218 deletions
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195
src/dynamics/solver/velocity_constraint_wide.rs
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@@ -4,12 +4,41 @@ use crate::geometry::{ContactManifold, ContactManifoldIndex};
use crate::math::{
AngVector, AngularInertia, Point, Real, SimdReal, Vector, DIM, MAX_MANIFOLD_POINTS, SIMD_WIDTH,
};
use crate::utils::{WAngularInertia, WBasis, WCross, WDot};
#[cfg(feature = "dim2")]
use crate::utils::WBasis;
use crate::utils::{WAngularInertia, WCross, WDot};
use num::Zero;
use simba::simd::{SimdPartialOrd, SimdValue};
#[derive(Copy, Clone, Debug)]
pub(crate) struct WVelocityConstraintElementPart {
pub(crate) struct WVelocityConstraintTangentPart {
pub gcross1: [AngVector<SimdReal>; DIM - 1],
pub gcross2: [AngVector<SimdReal>; DIM - 1],
pub rhs: [SimdReal; DIM - 1],
#[cfg(feature = "dim2")]
pub impulse: [SimdReal; DIM - 1],
#[cfg(feature = "dim3")]
pub impulse: na::Vector2<SimdReal>,
pub r: [SimdReal; DIM - 1],
}
impl WVelocityConstraintTangentPart {
pub fn zero() -> Self {
Self {
gcross1: [AngVector::zero(); DIM - 1],
gcross2: [AngVector::zero(); DIM - 1],
rhs: [SimdReal::zero(); DIM - 1],
#[cfg(feature = "dim2")]
impulse: [SimdReal::zero(); DIM - 1],
#[cfg(feature = "dim3")]
impulse: na::Vector2::zeros(),
r: [SimdReal::zero(); DIM - 1],
}
}
}
#[derive(Copy, Clone, Debug)]
pub(crate) struct WVelocityConstraintNormalPart {
pub gcross1: AngVector<SimdReal>,
pub gcross2: AngVector<SimdReal>,
pub rhs: SimdReal,
@@ -17,7 +46,7 @@ pub(crate) struct WVelocityConstraintElementPart {
pub r: SimdReal,
}
impl WVelocityConstraintElementPart {
impl WVelocityConstraintNormalPart {
pub fn zero() -> Self {
Self {
gcross1: AngVector::zero(),
@@ -31,15 +60,15 @@ impl WVelocityConstraintElementPart {
#[derive(Copy, Clone, Debug)]
pub(crate) struct WVelocityConstraintElement {
pub normal_part: WVelocityConstraintElementPart,
pub tangent_parts: [WVelocityConstraintElementPart; DIM - 1],
pub normal_part: WVelocityConstraintNormalPart,
pub tangent_part: WVelocityConstraintTangentPart,
}
impl WVelocityConstraintElement {
pub fn zero() -> Self {
Self {
normal_part: WVelocityConstraintElementPart::zero(),
tangent_parts: [WVelocityConstraintElementPart::zero(); DIM - 1],
normal_part: WVelocityConstraintNormalPart::zero(),
tangent_part: WVelocityConstraintTangentPart::zero(),
}
}
}
@@ -47,6 +76,10 @@ impl WVelocityConstraintElement {
#[derive(Copy, Clone, Debug)]
pub(crate) struct WVelocityConstraint {
pub dir1: Vector<SimdReal>, // Non-penetration force direction for the first body.
#[cfg(feature = "dim3")]
pub tangent1: Vector<SimdReal>, // One of the friction force directions.
#[cfg(feature = "dim3")]
pub tangent_rot1: na::UnitComplex<SimdReal>, // Orientation of the tangent basis wrt. the reference basis.
pub elements: [WVelocityConstraintElement; MAX_MANIFOLD_POINTS],
pub num_contacts: u8,
pub im1: SimdReal,
@@ -108,6 +141,12 @@ impl WVelocityConstraint {
let warmstart_coeff = warmstart_multiplier * SimdReal::splat(params.warmstart_coeff);
let num_active_contacts = manifolds[0].data.num_active_contacts();
#[cfg(feature = "dim2")]
let tangents1 = force_dir1.orthonormal_basis();
#[cfg(feature = "dim3")]
let (tangents1, tangent_rot1) =
super::compute_tangent_contact_directions(&force_dir1, &linvel1, &linvel2);
for l in (0..num_active_contacts).step_by(MAX_MANIFOLD_POINTS) {
let manifold_points = array![|ii|
&manifolds[ii].data.solver_contacts[l..num_active_contacts]; SIMD_WIDTH
@@ -116,6 +155,10 @@ impl WVelocityConstraint {
let mut constraint = WVelocityConstraint {
dir1: force_dir1,
#[cfg(feature = "dim3")]
tangent1: tangents1[0],
#[cfg(feature = "dim3")]
tangent_rot1,
elements: [WVelocityConstraintElement::zero(); MAX_MANIFOLD_POINTS],
im1,
im2,
@@ -169,7 +212,7 @@ impl WVelocityConstraint {
rhs +=
dist.simd_min(SimdReal::zero()) * (velocity_based_erp_inv_dt * is_resting);
constraint.elements[k].normal_part = WVelocityConstraintElementPart {
constraint.elements[k].normal_part = WVelocityConstraintNormalPart {
gcross1,
gcross2,
rhs,
@@ -179,31 +222,30 @@ impl WVelocityConstraint {
}
// tangent parts.
let tangents1 = force_dir1.orthonormal_basis();
#[cfg(feature = "dim2")]
let impulse = [SimdReal::from(
array![|ii| manifold_points[ii][k].data.tangent_impulse; SIMD_WIDTH],
)];
for j in 0..DIM - 1 {
#[cfg(feature = "dim2")]
let impulse = SimdReal::from(
#[cfg(feature = "dim3")]
let impulse = tangent_rot1
* na::Vector2::from(
array![|ii| manifold_points[ii][k].data.tangent_impulse; SIMD_WIDTH],
);
#[cfg(feature = "dim3")]
let impulse = SimdReal::from(
array![|ii| manifold_points[ii][k].data.tangent_impulse[j]; SIMD_WIDTH],
);
constraint.elements[k].tangent_part.impulse = impulse;
for j in 0..DIM - 1 {
let gcross1 = ii1.transform_vector(dp1.gcross(tangents1[j]));
let gcross2 = ii2.transform_vector(dp2.gcross(-tangents1[j]));
let r = SimdReal::splat(1.0)
/ (im1 + im2 + gcross1.gdot(gcross1) + gcross2.gdot(gcross2));
let rhs = (vel1 - vel2 + tangent_velocity).dot(&tangents1[j]);
constraint.elements[k].tangent_parts[j] = WVelocityConstraintElementPart {
gcross1,
gcross2,
rhs,
impulse: impulse * warmstart_coeff,
r,
};
constraint.elements[k].tangent_part.gcross1[j] = gcross1;
constraint.elements[k].tangent_part.gcross2[j] = gcross2;
constraint.elements[k].tangent_part.rhs[j] = rhs;
constraint.elements[k].tangent_part.r[j] = r;
}
}
@@ -235,6 +277,11 @@ impl WVelocityConstraint {
),
};
#[cfg(feature = "dim3")]
let tangents1 = [self.tangent1, self.dir1.cross(&self.tangent1)];
#[cfg(feature = "dim2")]
let tangents1 = self.dir1.orthonormal_basis();
for i in 0..self.num_contacts as usize {
let elt = &self.elements[i].normal_part;
mj_lambda1.linear += self.dir1 * (self.im1 * elt.impulse);
@@ -243,16 +290,13 @@ impl WVelocityConstraint {
mj_lambda2.linear += self.dir1 * (-self.im2 * elt.impulse);
mj_lambda2.angular += elt.gcross2 * elt.impulse;
// FIXME: move this out of the for loop?
let tangents1 = self.dir1.orthonormal_basis();
for j in 0..DIM - 1 {
let elt = &self.elements[i].tangent_parts[j];
mj_lambda1.linear += tangents1[j] * (self.im1 * elt.impulse);
mj_lambda1.angular += elt.gcross1 * elt.impulse;
let elt = &self.elements[i].tangent_part;
mj_lambda1.linear += tangents1[j] * (self.im1 * elt.impulse[j]);
mj_lambda1.angular += elt.gcross1[j] * elt.impulse[j];
mj_lambda2.linear += tangents1[j] * (-self.im2 * elt.impulse);
mj_lambda2.angular += elt.gcross2 * elt.impulse;
mj_lambda2.linear += tangents1[j] * (-self.im2 * elt.impulse[j]);
mj_lambda2.angular += elt.gcross2[j] * elt.impulse[j];
}
}
@@ -278,36 +322,71 @@ impl WVelocityConstraint {
let mut mj_lambda2 = DeltaVel {
linear: Vector::from(
array![ |ii| mj_lambdas[ self.mj_lambda2[ii] as usize].linear; SIMD_WIDTH],
array![|ii| mj_lambdas[ self.mj_lambda2[ii] as usize].linear; SIMD_WIDTH],
),
angular: AngVector::from(
array![ |ii| mj_lambdas[ self.mj_lambda2[ii] as usize].angular; SIMD_WIDTH],
array![|ii| mj_lambdas[ self.mj_lambda2[ii] as usize].angular; SIMD_WIDTH],
),
};
// Solve friction first.
// Solve friction.
#[cfg(feature = "dim3")]
let bitangent1 = self.dir1.cross(&self.tangent1);
#[cfg(feature = "dim2")]
let tangents1 = self.dir1.orthonormal_basis();
#[cfg(feature = "dim2")]
for i in 0..self.num_contacts as usize {
// FIXME: move this out of the for loop?
let tangents1 = self.dir1.orthonormal_basis();
let normal_elt = &self.elements[i].normal_part;
for j in 0..DIM - 1 {
let elt = &mut self.elements[i].tangent_parts[j];
let dimpulse = tangents1[j].dot(&mj_lambda1.linear)
+ elt.gcross1.gdot(mj_lambda1.angular)
- tangents1[j].dot(&mj_lambda2.linear)
+ elt.gcross2.gdot(mj_lambda2.angular)
+ elt.rhs;
let limit = self.limit * normal_elt.impulse;
let new_impulse = (elt.impulse - elt.r * dimpulse).simd_clamp(-limit, limit);
let dlambda = new_impulse - elt.impulse;
elt.impulse = new_impulse;
let elt = &mut self.elements[i].tangent_part;
let dimpulse = tangents1[0].dot(&mj_lambda1.linear)
+ elt.gcross1[0].gdot(mj_lambda1.angular)
- tangents1[0].dot(&mj_lambda2.linear)
+ elt.gcross2[0].gdot(mj_lambda2.angular)
+ elt.rhs[0];
let limit = self.limit * normal_elt.impulse;
let new_impulse = (elt.impulse[0] - elt.r[0] * dimpulse).simd_clamp(-limit, limit);
let dlambda = new_impulse - elt.impulse[0];
elt.impulse[0] = new_impulse;
mj_lambda1.linear += tangents1[j] * (self.im1 * dlambda);
mj_lambda1.angular += elt.gcross1 * dlambda;
mj_lambda2.linear += tangents1[j] * (-self.im2 * dlambda);
mj_lambda2.angular += elt.gcross2 * dlambda;
}
mj_lambda1.linear += tangents1[0] * (self.im1 * dlambda);
mj_lambda1.angular += elt.gcross1[0] * dlambda;
mj_lambda2.linear += tangents1[0] * (-self.im2 * dlambda);
mj_lambda2.angular += elt.gcross2[0] * dlambda;
}
#[cfg(feature = "dim3")]
for i in 0..self.num_contacts as usize {
let limit = self.limit * self.elements[i].normal_part.impulse;
let elts = &mut self.elements[i].tangent_part;
let dimpulse_0 = self.tangent1.dot(&mj_lambda1.linear)
+ elts.gcross1[0].gdot(mj_lambda1.angular)
- self.tangent1.dot(&mj_lambda2.linear)
+ elts.gcross2[0].gdot(mj_lambda2.angular)
+ elts.rhs[0];
let dimpulse_1 = bitangent1.dot(&mj_lambda1.linear)
+ elts.gcross1[1].gdot(mj_lambda1.angular)
- bitangent1.dot(&mj_lambda2.linear)
+ elts.gcross2[1].gdot(mj_lambda2.angular)
+ elts.rhs[1];
let new_impulse = na::Vector2::new(
elts.impulse[0] - elts.r[0] * dimpulse_0,
elts.impulse[1] - elts.r[1] * dimpulse_1,
);
let new_impulse = new_impulse.simd_cap_magnitude(limit);
let dlambda = new_impulse - elts.impulse;
elts.impulse = new_impulse;
mj_lambda1.linear +=
self.tangent1 * (self.im1 * dlambda[0]) + bitangent1 * (self.im1 * dlambda[1]);
mj_lambda1.angular += elts.gcross1[0] * dlambda[0] + elts.gcross1[1] * dlambda[1];
mj_lambda2.linear +=
self.tangent1 * (-self.im2 * dlambda[0]) + bitangent1 * (-self.im2 * dlambda[1]);
mj_lambda2.angular += elts.gcross2[0] * dlambda[0] + elts.gcross2[1] * dlambda[1];
}
// Solve non-penetration after friction.
@@ -340,11 +419,12 @@ impl WVelocityConstraint {
pub fn writeback_impulses(&self, manifolds_all: &mut [&mut ContactManifold]) {
for k in 0..self.num_contacts as usize {
let impulses: [_; SIMD_WIDTH] = self.elements[k].normal_part.impulse.into();
let tangent_impulses: [_; SIMD_WIDTH] =
self.elements[k].tangent_parts[0].impulse.into();
#[cfg(feature = "dim2")]
let tangent_impulses: [_; SIMD_WIDTH] = self.elements[k].tangent_part.impulse[0].into();
#[cfg(feature = "dim3")]
let bitangent_impulses: [_; SIMD_WIDTH] =
self.elements[k].tangent_parts[1].impulse.into();
let tangent_impulses = self
.tangent_rot1
.inverse_transform_vector(&self.elements[k].tangent_part.impulse);
for ii in 0..SIMD_WIDTH {
let manifold = &mut manifolds_all[self.manifold_id[ii]];
@@ -358,8 +438,7 @@ impl WVelocityConstraint {
}
#[cfg(feature = "dim3")]
{
active_contact.data.tangent_impulse =
[tangent_impulses[ii], bitangent_impulses[ii]];
active_contact.data.tangent_impulse = tangent_impulses.extract(ii);
}
}
}