use super::{AnyVelocityConstraint, DeltaVel};
use crate::dynamics::{IntegrationParameters, RigidBodySet};
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};
use num::Zero;
use simba::simd::{SimdPartialOrd, SimdValue};
#[derive(Copy, Clone, Debug)]
pub(crate) struct WVelocityGroundConstraintElementPart {
pub gcross2: AngVector<SimdReal>,
pub rhs: SimdReal,
pub impulse: SimdReal,
pub r: SimdReal,
}
impl WVelocityGroundConstraintElementPart {
pub fn zero() -> Self {
Self {
gcross2: AngVector::zero(),
rhs: SimdReal::zero(),
impulse: SimdReal::zero(),
r: SimdReal::zero(),
}
}
}
#[derive(Copy, Clone, Debug)]
pub(crate) struct WVelocityGroundConstraintElement {
pub normal_part: WVelocityGroundConstraintElementPart,
pub tangent_parts: [WVelocityGroundConstraintElementPart; DIM - 1],
}
impl WVelocityGroundConstraintElement {
pub fn zero() -> Self {
Self {
normal_part: WVelocityGroundConstraintElementPart::zero(),
tangent_parts: [WVelocityGroundConstraintElementPart::zero(); DIM - 1],
}
}
}
#[derive(Copy, Clone, Debug)]
pub(crate) struct WVelocityGroundConstraint {
pub dir1: Vector<SimdReal>, pub elements: [WVelocityGroundConstraintElement; MAX_MANIFOLD_POINTS],
pub num_contacts: u8,
pub im2: SimdReal,
pub limit: SimdReal,
pub mj_lambda2: [usize; SIMD_WIDTH],
pub manifold_id: [ContactManifoldIndex; SIMD_WIDTH],
pub manifold_contact_id: usize,
}
impl WVelocityGroundConstraint {
pub fn generate(
params: &IntegrationParameters,
manifold_id: [ContactManifoldIndex; SIMD_WIDTH],
manifolds: [&ContactManifold; SIMD_WIDTH],
bodies: &RigidBodySet,
out_constraints: &mut Vec<AnyVelocityConstraint>,
push: bool,
) {
let inv_dt = SimdReal::splat(params.inv_dt());
let mut rbs1 = array![|ii| &bodies[manifolds[ii].data.body_pair.body1]; SIMD_WIDTH];
let mut rbs2 = array![|ii| &bodies[manifolds[ii].data.body_pair.body2]; SIMD_WIDTH];
let mut flipped = [false; SIMD_WIDTH];
for ii in 0..SIMD_WIDTH {
if !rbs2[ii].is_dynamic() {
std::mem::swap(&mut rbs1[ii], &mut rbs2[ii]);
flipped[ii] = true;
}
}
let im2 = SimdReal::from(array![|ii| rbs2[ii].effective_inv_mass; SIMD_WIDTH]);
let ii2: AngularInertia<SimdReal> = AngularInertia::from(
array![|ii| rbs2[ii].effective_world_inv_inertia_sqrt; SIMD_WIDTH],
);
let linvel1 = Vector::from(array![|ii| rbs1[ii].linvel; SIMD_WIDTH]);
let angvel1 = AngVector::<SimdReal>::from(array![|ii| rbs1[ii].angvel; SIMD_WIDTH]);
let linvel2 = Vector::from(array![|ii| rbs2[ii].linvel; SIMD_WIDTH]);
let angvel2 = AngVector::<SimdReal>::from(array![|ii| rbs2[ii].angvel; SIMD_WIDTH]);
let world_com1 = Point::from(array![|ii| rbs1[ii].world_com; SIMD_WIDTH]);
let world_com2 = Point::from(array![|ii| rbs2[ii].world_com; SIMD_WIDTH]);
let force_dir1 = Vector::from(
array![|ii| if flipped[ii] { manifolds[ii].data.normal } else { -manifolds[ii].data.normal }; SIMD_WIDTH],
);
let mj_lambda2 = array![|ii| rbs2[ii].active_set_offset; SIMD_WIDTH];
let restitution_velocity_threshold = SimdReal::splat(params.restitution_velocity_threshold);
let warmstart_multiplier =
SimdReal::from(array![|ii| manifolds[ii].data.warmstart_multiplier; SIMD_WIDTH]);
let warmstart_coeff = warmstart_multiplier * SimdReal::splat(params.warmstart_coeff);
let num_active_contacts = manifolds[0].data.num_active_contacts();
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,
elements: [WVelocityGroundConstraintElement::zero(); MAX_MANIFOLD_POINTS],
im2,
limit: SimdReal::splat(0.0),
mj_lambda2,
manifold_id,
manifold_contact_id: l,
num_contacts: num_points as u8,
};
for k in 0..num_points {
let friction =
SimdReal::from(array![|ii| manifold_points[ii][k].friction; SIMD_WIDTH]);
let restitution =
SimdReal::from(array![|ii| manifold_points[ii][k].restitution; SIMD_WIDTH]);
let point = Point::from(array![|ii| manifold_points[ii][k].point; SIMD_WIDTH]);
let dist = SimdReal::from(array![|ii| manifold_points[ii][k].dist; SIMD_WIDTH]);
let impulse =
SimdReal::from(array![|ii| manifold_points[ii][k].data.impulse; SIMD_WIDTH]);
let dp1 = point - world_com1;
let dp2 = point - world_com2;
let vel1 = linvel1 + angvel1.gcross(dp1);
let vel2 = linvel2 + angvel2.gcross(dp2);
constraint.limit = friction;
{
let gcross2 = ii2.transform_vector(dp2.gcross(-force_dir1));
let r = SimdReal::splat(1.0) / (im2 + gcross2.gdot(gcross2));
let mut rhs = (vel1 - vel2).dot(&force_dir1);
let use_restitution = rhs.simd_le(-restitution_velocity_threshold);
let rhs_with_restitution = rhs + rhs * restitution;
rhs = rhs_with_restitution.select(use_restitution, rhs);
rhs += dist.simd_max(SimdReal::zero()) * inv_dt;
constraint.elements[k].normal_part = WVelocityGroundConstraintElementPart {
gcross2,
rhs,
impulse: impulse * warmstart_coeff,
r,
};
}
let tangents1 = force_dir1.orthonormal_basis();
for j in 0..DIM - 1 {
#[cfg(feature = "dim2")]
let impulse = SimdReal::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],
);
let gcross2 = ii2.transform_vector(dp2.gcross(-tangents1[j]));
let r = SimdReal::splat(1.0) / (im2 + gcross2.gdot(gcross2));
let rhs = -vel2.dot(&tangents1[j]) + vel1.dot(&tangents1[j]);
constraint.elements[k].tangent_parts[j] =
WVelocityGroundConstraintElementPart {
gcross2,
rhs,
impulse: impulse * warmstart_coeff,
r,
};
}
}
if push {
out_constraints.push(AnyVelocityConstraint::GroupedGround(constraint));
} else {
out_constraints[manifolds[0].data.constraint_index + l / MAX_MANIFOLD_POINTS] =
AnyVelocityConstraint::GroupedGround(constraint);
}
}
}
pub fn warmstart(&self, mj_lambdas: &mut [DeltaVel<Real>]) {
let mut mj_lambda2 = DeltaVel {
linear: Vector::from(
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],
),
};
let tangents1 = self.dir1.orthonormal_basis();
for i in 0..self.num_contacts as usize {
let elt = &self.elements[i].normal_part;
mj_lambda2.linear += self.dir1 * (-self.im2 * elt.impulse);
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;
}
}
for ii in 0..SIMD_WIDTH {
mj_lambdas[self.mj_lambda2[ii] as usize].linear = mj_lambda2.linear.extract(ii);
mj_lambdas[self.mj_lambda2[ii] as usize].angular = mj_lambda2.angular.extract(ii);
}
}
pub fn solve(&mut self, mj_lambdas: &mut [DeltaVel<Real>]) {
let mut mj_lambda2 = DeltaVel {
linear: Vector::from(
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],
),
};
let tangents1 = self.dir1.orthonormal_basis();
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;
mj_lambda2.linear += tangents1[j] * (-self.im2 * dlambda);
mj_lambda2.angular += elt.gcross2 * dlambda;
}
}
for i in 0..self.num_contacts as usize {
let elt = &mut self.elements[i].normal_part;
let dimpulse =
-self.dir1.dot(&mj_lambda2.linear) + elt.gcross2.gdot(mj_lambda2.angular) + elt.rhs;
let new_impulse = (elt.impulse - elt.r * dimpulse).simd_max(SimdReal::zero());
let dlambda = new_impulse - elt.impulse;
elt.impulse = new_impulse;
mj_lambda2.linear += self.dir1 * (-self.im2 * dlambda);
mj_lambda2.angular += elt.gcross2 * dlambda;
}
for ii in 0..SIMD_WIDTH {
mj_lambdas[self.mj_lambda2[ii] as usize].linear = mj_lambda2.linear.extract(ii);
mj_lambdas[self.mj_lambda2[ii] as usize].angular = mj_lambda2.angular.extract(ii);
}
}
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 = "dim3")]
let bitangent_impulses: [_; SIMD_WIDTH] =
self.elements[k].tangent_parts[1].impulse.into();
for ii in 0..SIMD_WIDTH {
let manifold = &mut manifolds_all[self.manifold_id[ii]];
let k_base = self.manifold_contact_id;
let active_contacts = &mut manifold.points[..manifold.data.num_active_contacts()];
active_contacts[k_base + k].data.impulse = impulses[ii];
#[cfg(feature = "dim2")]
{
active_contacts[k_base + k].data.tangent_impulse = tangent_impulses[ii];
}
#[cfg(feature = "dim3")]
{
active_contacts[k_base + k].data.tangent_impulse =
[tangent_impulses[ii], bitangent_impulses[ii]];
}
}
}
}
}