nichkara/rapier
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

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

Browse Source
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
Download Patch File Download Diff File Expand all files Collapse all files

159
src/dynamics/solver/velocity_ground_constraint_wide.rs
View File

@@ -4,19 +4,46 @@ 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 WVelocityGroundConstraintElementPart {
pub(crate) struct WVelocityGroundConstraintTangentPart {
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 WVelocityGroundConstraintTangentPart {
pub fn zero() -> Self {
Self {
gcross2: [AngVector::zero(); DIM - 1],
rhs: [SimdReal::zero(); DIM - 1],
#[cfg(feature = "dim2")]
impulse: [SimdReal::zero(); DIM - 1],
#[cfg(feature = "dim3")]
impulse: na::zero(),
r: [SimdReal::zero(); DIM - 1],
}
}
}
#[derive(Copy, Clone, Debug)]
pub(crate) struct WVelocityGroundConstraintNormalPart {
pub gcross2: AngVector<SimdReal>,
pub rhs: SimdReal,
pub impulse: SimdReal,
pub r: SimdReal,
}
impl WVelocityGroundConstraintElementPart {
impl WVelocityGroundConstraintNormalPart {
pub fn zero() -> Self {
Self {
gcross2: AngVector::zero(),
@@ -29,15 +56,15 @@ impl WVelocityGroundConstraintElementPart {
#[derive(Copy, Clone, Debug)]
pub(crate) struct WVelocityGroundConstraintElement {
pub normal_part: WVelocityGroundConstraintElementPart,
pub tangent_parts: [WVelocityGroundConstraintElementPart; DIM - 1],
pub normal_part: WVelocityGroundConstraintNormalPart,
pub tangent_part: WVelocityGroundConstraintTangentPart,
}
impl WVelocityGroundConstraintElement {
pub fn zero() -> Self {
Self {
normal_part: WVelocityGroundConstraintElementPart::zero(),
tangent_parts: [WVelocityGroundConstraintElementPart::zero(); DIM - 1],
normal_part: WVelocityGroundConstraintNormalPart::zero(),
tangent_part: WVelocityGroundConstraintTangentPart::zero(),
}
}
}
@@ -45,6 +72,10 @@ impl WVelocityGroundConstraintElement {
#[derive(Copy, Clone, Debug)]
pub(crate) struct WVelocityGroundConstraint {
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: [WVelocityGroundConstraintElement; MAX_MANIFOLD_POINTS],
pub num_contacts: u8,
pub im2: SimdReal,
@@ -104,12 +135,22 @@ impl WVelocityGroundConstraint {
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..]; SIMD_WIDTH];
let num_points = manifold_points[0].len().min(MAX_MANIFOLD_POINTS);
let mut constraint = WVelocityGroundConstraint {
dir1: force_dir1,
#[cfg(feature = "dim3")]
tangent1: tangents1[0],
#[cfg(feature = "dim3")]
tangent_rot1,
elements: [WVelocityGroundConstraintElement::zero(); MAX_MANIFOLD_POINTS],
im2,
limit: SimdReal::splat(0.0),
@@ -158,7 +199,7 @@ impl WVelocityGroundConstraint {
rhs +=
dist.simd_min(SimdReal::zero()) * (velocity_based_erp_inv_dt * is_resting);
constraint.elements[k].normal_part = WVelocityGroundConstraintElementPart {
constraint.elements[k].normal_part = WVelocityGroundConstraintNormalPart {
gcross2,
rhs,
impulse: impulse * warmstart_coeff,
@@ -167,29 +208,25 @@ impl WVelocityGroundConstraint {
}
// tangent parts.
let tangents1 = force_dir1.orthonormal_basis();
for j in 0..DIM - 1 {
#[cfg(feature = "dim2")]
let impulse = SimdReal::from(
#[cfg(feature = "dim2")]
let impulse = [SimdReal::from(
array![|ii| manifold_points[ii][k].data.tangent_impulse; SIMD_WIDTH],
)];
#[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 gcross2 = ii2.transform_vector(dp2.gcross(-tangents1[j]));
let r = SimdReal::splat(1.0) / (im2 + gcross2.gdot(gcross2));
let rhs = (vel1 - vel2 + tangent_velocity * flipped_sign).dot(&tangents1[j]);
constraint.elements[k].tangent_parts[j] =
WVelocityGroundConstraintElementPart {
gcross2,
rhs,
impulse: impulse * warmstart_coeff,
r,
};
constraint.elements[k].tangent_part.gcross2[j] = gcross2;
constraint.elements[k].tangent_part.r[j] = r;
constraint.elements[k].tangent_part.rhs[j] = rhs;
}
}
@@ -212,6 +249,9 @@ impl WVelocityGroundConstraint {
),
};
#[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 {
@@ -220,9 +260,9 @@ impl WVelocityGroundConstraint {
mj_lambda2.angular += elt.gcross2 * elt.impulse;
for j in 0..DIM - 1 {
let elt = &self.elements[i].tangent_parts[j];
mj_lambda2.linear += tangents1[j] * (-self.im2 * elt.impulse);
mj_lambda2.angular += elt.gcross2 * elt.impulse;
let elt = &self.elements[i].tangent_part;
mj_lambda2.linear += tangents1[j] * (-self.im2 * elt.impulse[j]);
mj_lambda2.angular += elt.gcross2[j] * elt.impulse[j];
}
}
@@ -242,25 +282,52 @@ impl WVelocityGroundConstraint {
),
};
// 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 {
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_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_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_lambda2.linear += tangents1[j] * (-self.im2 * dlambda);
mj_lambda2.angular += elt.gcross2 * 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_lambda2.linear)
+ elts.gcross2[0].gdot(mj_lambda2.angular)
+ elts.rhs[0];
let dimpulse_1 = -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_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.
@@ -286,11 +353,12 @@ impl WVelocityGroundConstraint {
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]];
@@ -304,8 +372,7 @@ impl WVelocityGroundConstraint {
}
#[cfg(feature = "dim3")]
{
active_contact.data.tangent_impulse =
[tangent_impulses[ii], bitangent_impulses[ii]];
active_contact.data.tangent_impulse = tangent_impulses.extract(ii);
}
}
}