use super::{
AnyVelocityConstraint, DeltaVel, VelocityGroundConstraintElement,
VelocityGroundConstraintNormalPart,
};
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,
};
#[cfg(feature = "dim2")]
use crate::utils::WBasis;
use crate::utils::{WAngularInertia, WCross, WDot};
use na::SimdComplexField;
use num::Zero;
use simba::simd::{SimdPartialOrd, SimdValue};
#[derive(Copy, Clone, Debug)]
pub(crate) struct WVelocityGroundConstraint {
pub dir1: Vector<SimdReal>, #[cfg(feature = "dim3")]
pub tangent1: Vector<SimdReal>, #[cfg(feature = "dim3")]
pub tangent_rot1: na::UnitComplex<SimdReal>, pub elements: [VelocityGroundConstraintElement<SimdReal>; 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: [[u8; SIMD_WIDTH]; MAX_MANIFOLD_POINTS],
}
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 velocity_solve_fraction = SimdReal::splat(params.velocity_solve_fraction);
let velocity_based_erp_inv_dt = SimdReal::splat(params.velocity_based_erp_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 = [1.0; SIMD_WIDTH];
for ii in 0..SIMD_WIDTH {
if manifolds[ii].data.relative_dominance < 0 {
std::mem::swap(&mut rbs1[ii], &mut rbs2[ii]);
flipped[ii] = -1.0;
}
}
let flipped_sign = SimdReal::from(flipped);
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 normal1 = Vector::from(array![|ii| manifolds[ii].data.normal; SIMD_WIDTH]);
let force_dir1 = normal1 * -flipped_sign;
let mj_lambda2 = array![|ii| rbs2[ii].active_set_offset; SIMD_WIDTH];
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 warmstart_correction_slope = SimdReal::splat(params.warmstart_correction_slope);
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: [VelocityGroundConstraintElement::zero(); MAX_MANIFOLD_POINTS],
im2,
limit: SimdReal::splat(0.0),
mj_lambda2,
manifold_id,
manifold_contact_id: [[0; SIMD_WIDTH]; MAX_MANIFOLD_POINTS],
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 is_bouncy = SimdReal::from(
array![|ii| manifold_points[ii][k].is_bouncy() as u32 as Real; SIMD_WIDTH],
);
let is_resting = SimdReal::splat(1.0) - is_bouncy;
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 tangent_velocity =
Vector::from(array![|ii| manifold_points[ii][k].tangent_velocity; SIMD_WIDTH]);
let impulse = SimdReal::from(
array![|ii| manifold_points[ii][k].warmstart_impulse; SIMD_WIDTH],
);
let prev_rhs =
SimdReal::from(array![|ii| manifold_points[ii][k].prev_rhs; SIMD_WIDTH]);
let dp1 = point - world_com1;
let dp2 = point - world_com2;
let vel1 = linvel1 + angvel1.gcross(dp1);
let vel2 = linvel2 + angvel2.gcross(dp2);
let warmstart_correction;
constraint.limit = friction;
constraint.manifold_contact_id[k] =
array![|ii| manifold_points[ii][k].contact_id; SIMD_WIDTH];
{
let gcross2 = ii2.transform_vector(dp2.gcross(-force_dir1));
let r = SimdReal::splat(1.0) / (im2 + gcross2.gdot(gcross2));
let projected_velocity = (vel1 - vel2).dot(&force_dir1);
let mut rhs =
(SimdReal::splat(1.0) + is_bouncy * restitution) * projected_velocity;
rhs += dist.simd_max(SimdReal::zero()) * inv_dt;
rhs *= is_bouncy + is_resting * velocity_solve_fraction;
rhs +=
dist.simd_min(SimdReal::zero()) * (velocity_based_erp_inv_dt * is_resting);
warmstart_correction = (warmstart_correction_slope
/ (rhs - prev_rhs).simd_abs())
.simd_min(warmstart_coeff);
constraint.elements[k].normal_part = VelocityGroundConstraintNormalPart {
gcross2,
rhs,
impulse: impulse * warmstart_correction,
r,
};
}
#[cfg(feature = "dim2")]
let impulse = [SimdReal::from(
array![|ii| manifold_points[ii][k].warmstart_tangent_impulse; SIMD_WIDTH],
) * warmstart_correction];
#[cfg(feature = "dim3")]
let impulse = tangent_rot1
* na::Vector2::from(
array![|ii| manifold_points[ii][k].warmstart_tangent_impulse; SIMD_WIDTH],
)
* warmstart_correction;
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_part.gcross2[j] = gcross2;
constraint.elements[k].tangent_part.r[j] = r;
constraint.elements[k].tangent_part.rhs[j] = rhs;
}
}
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],
),
};
VelocityGroundConstraintElement::warmstart_group(
&self.elements[..self.num_contacts as usize],
&self.dir1,
#[cfg(feature = "dim3")]
&self.tangent1,
self.im2,
&mut mj_lambda2,
);
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],
),
};
VelocityGroundConstraintElement::solve_group(
&mut self.elements[..self.num_contacts as usize],
&self.dir1,
#[cfg(feature = "dim3")]
&self.tangent1,
self.im2,
self.limit,
&mut mj_lambda2,
);
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 rhs: [_; SIMD_WIDTH] = self.elements[k].normal_part.rhs.into();
let impulses: [_; SIMD_WIDTH] = self.elements[k].normal_part.impulse.into();
#[cfg(feature = "dim2")]
let tangent_impulses: [_; SIMD_WIDTH] = self.elements[k].tangent_part.impulse[0].into();
#[cfg(feature = "dim3")]
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]];
let contact_id = self.manifold_contact_id[k][ii];
let active_contact = &mut manifold.points[contact_id as usize];
active_contact.data.rhs = rhs[ii];
active_contact.data.impulse = impulses[ii];
#[cfg(feature = "dim2")]
{
active_contact.data.tangent_impulse = tangent_impulses[ii];
}
#[cfg(feature = "dim3")]
{
active_contact.data.tangent_impulse = tangent_impulses.extract(ii);
}
}
}
}
}