408 lines
16 KiB
Rust
408 lines
16 KiB
Rust
use super::DeltaVel;
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use crate::dynamics::solver::VelocityGroundConstraint;
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#[cfg(feature = "simd-is-enabled")]
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use crate::dynamics::solver::{WVelocityConstraint, WVelocityGroundConstraint};
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use crate::dynamics::{IntegrationParameters, RigidBodySet};
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use crate::geometry::{ContactManifold, ContactManifoldIndex};
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use crate::math::{AngVector, Real, Vector, DIM, MAX_MANIFOLD_POINTS};
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use crate::utils::{WAngularInertia, WBasis, WCross, WDot};
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use simba::simd::SimdPartialOrd;
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//#[repr(align(64))]
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#[derive(Copy, Clone, Debug)]
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pub(crate) enum AnyVelocityConstraint {
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NongroupedGround(VelocityGroundConstraint),
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Nongrouped(VelocityConstraint),
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#[cfg(feature = "simd-is-enabled")]
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GroupedGround(WVelocityGroundConstraint),
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#[cfg(feature = "simd-is-enabled")]
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Grouped(WVelocityConstraint),
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#[allow(dead_code)] // The Empty variant is only used with parallel code.
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Empty,
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}
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impl AnyVelocityConstraint {
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#[cfg(target_arch = "wasm32")]
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pub fn as_nongrouped_mut(&mut self) -> Option<&mut VelocityConstraint> {
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if let AnyVelocityConstraint::Nongrouped(c) = self {
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Some(c)
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} else {
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None
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}
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}
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#[cfg(target_arch = "wasm32")]
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pub fn as_nongrouped_ground_mut(&mut self) -> Option<&mut VelocityGroundConstraint> {
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if let AnyVelocityConstraint::NongroupedGround(c) = self {
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Some(c)
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} else {
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None
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}
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}
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pub fn warmstart(&self, mj_lambdas: &mut [DeltaVel<Real>]) {
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match self {
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AnyVelocityConstraint::NongroupedGround(c) => c.warmstart(mj_lambdas),
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AnyVelocityConstraint::Nongrouped(c) => c.warmstart(mj_lambdas),
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#[cfg(feature = "simd-is-enabled")]
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AnyVelocityConstraint::GroupedGround(c) => c.warmstart(mj_lambdas),
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#[cfg(feature = "simd-is-enabled")]
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AnyVelocityConstraint::Grouped(c) => c.warmstart(mj_lambdas),
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AnyVelocityConstraint::Empty => unreachable!(),
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}
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}
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pub fn solve(&mut self, mj_lambdas: &mut [DeltaVel<Real>]) {
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match self {
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AnyVelocityConstraint::NongroupedGround(c) => c.solve(mj_lambdas),
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AnyVelocityConstraint::Nongrouped(c) => c.solve(mj_lambdas),
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#[cfg(feature = "simd-is-enabled")]
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AnyVelocityConstraint::GroupedGround(c) => c.solve(mj_lambdas),
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#[cfg(feature = "simd-is-enabled")]
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AnyVelocityConstraint::Grouped(c) => c.solve(mj_lambdas),
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AnyVelocityConstraint::Empty => unreachable!(),
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}
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}
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pub fn writeback_impulses(&self, manifold_all: &mut [&mut ContactManifold]) {
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match self {
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AnyVelocityConstraint::NongroupedGround(c) => c.writeback_impulses(manifold_all),
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AnyVelocityConstraint::Nongrouped(c) => c.writeback_impulses(manifold_all),
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#[cfg(feature = "simd-is-enabled")]
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AnyVelocityConstraint::GroupedGround(c) => c.writeback_impulses(manifold_all),
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#[cfg(feature = "simd-is-enabled")]
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AnyVelocityConstraint::Grouped(c) => c.writeback_impulses(manifold_all),
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AnyVelocityConstraint::Empty => unreachable!(),
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}
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}
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}
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#[derive(Copy, Clone, Debug)]
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pub(crate) struct VelocityConstraintElementPart {
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pub gcross1: AngVector<Real>,
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pub gcross2: AngVector<Real>,
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pub rhs: Real,
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pub impulse: Real,
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pub r: Real,
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}
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#[cfg(not(target_arch = "wasm32"))]
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impl VelocityConstraintElementPart {
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fn zero() -> Self {
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Self {
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gcross1: na::zero(),
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gcross2: na::zero(),
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rhs: 0.0,
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impulse: 0.0,
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r: 0.0,
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}
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}
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}
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#[derive(Copy, Clone, Debug)]
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pub(crate) struct VelocityConstraintElement {
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pub normal_part: VelocityConstraintElementPart,
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pub tangent_part: [VelocityConstraintElementPart; DIM - 1],
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}
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#[cfg(not(target_arch = "wasm32"))]
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impl VelocityConstraintElement {
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pub fn zero() -> Self {
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Self {
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normal_part: VelocityConstraintElementPart::zero(),
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tangent_part: [VelocityConstraintElementPart::zero(); DIM - 1],
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}
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}
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}
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#[derive(Copy, Clone, Debug)]
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pub(crate) struct VelocityConstraint {
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pub dir1: Vector<Real>, // Non-penetration force direction for the first body.
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pub im1: Real,
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pub im2: Real,
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pub limit: Real,
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pub mj_lambda1: usize,
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pub mj_lambda2: usize,
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pub manifold_id: ContactManifoldIndex,
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pub manifold_contact_id: usize,
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pub num_contacts: u8,
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pub elements: [VelocityConstraintElement; MAX_MANIFOLD_POINTS],
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}
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impl VelocityConstraint {
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#[cfg(feature = "parallel")]
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pub fn num_active_constraints(manifold: &ContactManifold) -> usize {
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let rest = manifold.data.solver_contacts.len() % MAX_MANIFOLD_POINTS != 0;
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manifold.data.solver_contacts.len() / MAX_MANIFOLD_POINTS + rest as usize
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}
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pub fn generate(
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params: &IntegrationParameters,
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manifold_id: ContactManifoldIndex,
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manifold: &ContactManifold,
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bodies: &RigidBodySet,
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out_constraints: &mut Vec<AnyVelocityConstraint>,
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push: bool,
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) {
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let inv_dt = params.inv_dt();
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let rb1 = &bodies[manifold.data.body_pair.body1];
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let rb2 = &bodies[manifold.data.body_pair.body2];
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let mj_lambda1 = rb1.active_set_offset;
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let mj_lambda2 = rb2.active_set_offset;
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let force_dir1 = -manifold.data.normal;
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let warmstart_coeff = manifold.data.warmstart_multiplier * params.warmstart_coeff;
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for (l, manifold_points) in manifold
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.data
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.solver_contacts
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.chunks(MAX_MANIFOLD_POINTS)
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.enumerate()
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{
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#[cfg(not(target_arch = "wasm32"))]
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let mut constraint = VelocityConstraint {
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dir1: force_dir1,
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elements: [VelocityConstraintElement::zero(); MAX_MANIFOLD_POINTS],
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im1: rb1.effective_inv_mass,
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im2: rb2.effective_inv_mass,
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limit: 0.0,
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mj_lambda1,
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mj_lambda2,
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manifold_id,
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manifold_contact_id: l * MAX_MANIFOLD_POINTS,
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num_contacts: manifold_points.len() as u8,
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};
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// TODO: this is a WIP optimization for WASM platforms.
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// For some reasons, the compiler does not inline the `Vec::push` method
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// in this method. This generates two memset and one memcpy which are both very
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// expansive.
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// This would likely be solved by some kind of "placement-push" (like emplace in C++).
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// In the mean time, a workaround is to "push" using `.resize_with` and `::uninit()` to
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// avoid spurious copying.
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// Is this optimization beneficial when targeting non-WASM platforms?
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//
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// NOTE: joints have the same problem, but it is not easy to refactor the code that way
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// for the moment.
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#[cfg(target_arch = "wasm32")]
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let constraint = if push {
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let new_len = out_constraints.len() + 1;
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unsafe {
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out_constraints.resize_with(new_len, || {
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AnyVelocityConstraint::Nongrouped(
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std::mem::MaybeUninit::uninit().assume_init(),
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)
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});
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}
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out_constraints
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.last_mut()
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.unwrap()
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.as_nongrouped_mut()
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.unwrap()
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} else {
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unreachable!(); // We don't have parallelization on WASM yet, so this is unreachable.
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};
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#[cfg(target_arch = "wasm32")]
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{
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constraint.dir1 = force_dir1;
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constraint.im1 = rb1.effective_inv_mass;
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constraint.im2 = rb2.effective_inv_mass;
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constraint.limit = 0.0;
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constraint.mj_lambda1 = mj_lambda1;
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constraint.mj_lambda2 = mj_lambda2;
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constraint.manifold_id = manifold_id;
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constraint.manifold_contact_id = l * MAX_MANIFOLD_POINTS;
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constraint.num_contacts = manifold_points.len() as u8;
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}
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for k in 0..manifold_points.len() {
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let manifold_point = &manifold_points[k];
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let dp1 = manifold_point.point - rb1.world_com;
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let dp2 = manifold_point.point - rb2.world_com;
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let vel1 = rb1.linvel + rb1.angvel.gcross(dp1);
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let vel2 = rb2.linvel + rb2.angvel.gcross(dp2);
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constraint.limit = manifold_point.friction;
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// Normal part.
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{
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let gcross1 = rb1
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.effective_world_inv_inertia_sqrt
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.transform_vector(dp1.gcross(force_dir1));
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let gcross2 = rb2
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.effective_world_inv_inertia_sqrt
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.transform_vector(dp2.gcross(-force_dir1));
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let r = 1.0
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/ (rb1.effective_inv_mass
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+ rb2.effective_inv_mass
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+ gcross1.gdot(gcross1)
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+ gcross2.gdot(gcross2));
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let mut rhs = (vel1 - vel2).dot(&force_dir1);
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if rhs <= -params.restitution_velocity_threshold {
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rhs += manifold_point.restitution * rhs
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}
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rhs += manifold_point.dist.max(0.0) * inv_dt;
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let impulse = manifold_point.data.impulse * warmstart_coeff;
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constraint.elements[k].normal_part = VelocityConstraintElementPart {
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gcross1,
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gcross2,
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rhs,
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impulse,
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r,
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};
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}
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// Tangent parts.
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{
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let tangents1 = force_dir1.orthonormal_basis();
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for j in 0..DIM - 1 {
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let gcross1 = rb1
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.effective_world_inv_inertia_sqrt
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.transform_vector(dp1.gcross(tangents1[j]));
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let gcross2 = rb2
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.effective_world_inv_inertia_sqrt
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.transform_vector(dp2.gcross(-tangents1[j]));
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let r = 1.0
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/ (rb1.effective_inv_mass
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+ rb2.effective_inv_mass
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+ gcross1.gdot(gcross1)
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+ gcross2.gdot(gcross2));
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let rhs = (vel1 - vel2).dot(&tangents1[j]);
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#[cfg(feature = "dim2")]
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let impulse = manifold_point.data.tangent_impulse * warmstart_coeff;
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#[cfg(feature = "dim3")]
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let impulse = manifold_point.data.tangent_impulse[j] * warmstart_coeff;
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constraint.elements[k].tangent_part[j] = VelocityConstraintElementPart {
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gcross1,
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gcross2,
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rhs,
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impulse,
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r,
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};
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}
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}
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}
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#[cfg(not(target_arch = "wasm32"))]
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if push {
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out_constraints.push(AnyVelocityConstraint::Nongrouped(constraint));
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} else {
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out_constraints[manifold.data.constraint_index + l] =
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AnyVelocityConstraint::Nongrouped(constraint);
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}
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}
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}
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pub fn warmstart(&self, mj_lambdas: &mut [DeltaVel<Real>]) {
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let mut mj_lambda1 = DeltaVel::zero();
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let mut mj_lambda2 = DeltaVel::zero();
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for i in 0..self.num_contacts as usize {
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let elt = &self.elements[i].normal_part;
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mj_lambda1.linear += self.dir1 * (self.im1 * elt.impulse);
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mj_lambda1.angular += elt.gcross1 * elt.impulse;
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mj_lambda2.linear += self.dir1 * (-self.im2 * elt.impulse);
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mj_lambda2.angular += elt.gcross2 * elt.impulse;
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// FIXME: move this out of the for loop?
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let tangents1 = self.dir1.orthonormal_basis();
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for j in 0..DIM - 1 {
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let elt = &self.elements[i].tangent_part[j];
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mj_lambda1.linear += tangents1[j] * (self.im1 * elt.impulse);
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mj_lambda1.angular += elt.gcross1 * elt.impulse;
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mj_lambda2.linear += tangents1[j] * (-self.im2 * elt.impulse);
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mj_lambda2.angular += elt.gcross2 * elt.impulse;
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}
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}
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mj_lambdas[self.mj_lambda1 as usize].linear += mj_lambda1.linear;
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mj_lambdas[self.mj_lambda1 as usize].angular += mj_lambda1.angular;
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mj_lambdas[self.mj_lambda2 as usize].linear += mj_lambda2.linear;
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mj_lambdas[self.mj_lambda2 as usize].angular += mj_lambda2.angular;
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}
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pub fn solve(&mut self, mj_lambdas: &mut [DeltaVel<Real>]) {
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let mut mj_lambda1 = mj_lambdas[self.mj_lambda1 as usize];
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let mut mj_lambda2 = mj_lambdas[self.mj_lambda2 as usize];
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// Solve friction.
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for i in 0..self.num_contacts as usize {
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let tangents1 = self.dir1.orthonormal_basis();
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for j in 0..DIM - 1 {
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let normal_elt = &self.elements[i].normal_part;
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let elt = &mut self.elements[i].tangent_part[j];
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let dimpulse = tangents1[j].dot(&mj_lambda1.linear)
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+ elt.gcross1.gdot(mj_lambda1.angular)
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- tangents1[j].dot(&mj_lambda2.linear)
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+ elt.gcross2.gdot(mj_lambda2.angular)
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+ elt.rhs;
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let limit = self.limit * normal_elt.impulse;
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let new_impulse = (elt.impulse - elt.r * dimpulse).simd_clamp(-limit, limit);
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let dlambda = new_impulse - elt.impulse;
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elt.impulse = new_impulse;
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mj_lambda1.linear += tangents1[j] * (self.im1 * dlambda);
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mj_lambda1.angular += elt.gcross1 * dlambda;
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mj_lambda2.linear += tangents1[j] * (-self.im2 * dlambda);
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mj_lambda2.angular += elt.gcross2 * dlambda;
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}
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}
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// Solve non-penetration.
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for i in 0..self.num_contacts as usize {
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let elt = &mut self.elements[i].normal_part;
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let dimpulse = self.dir1.dot(&mj_lambda1.linear) + elt.gcross1.gdot(mj_lambda1.angular)
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- self.dir1.dot(&mj_lambda2.linear)
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+ elt.gcross2.gdot(mj_lambda2.angular)
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+ elt.rhs;
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let new_impulse = (elt.impulse - elt.r * dimpulse).max(0.0);
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let dlambda = new_impulse - elt.impulse;
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elt.impulse = new_impulse;
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mj_lambda1.linear += self.dir1 * (self.im1 * dlambda);
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mj_lambda1.angular += elt.gcross1 * dlambda;
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mj_lambda2.linear += self.dir1 * (-self.im2 * dlambda);
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mj_lambda2.angular += elt.gcross2 * dlambda;
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}
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mj_lambdas[self.mj_lambda1 as usize] = mj_lambda1;
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mj_lambdas[self.mj_lambda2 as usize] = mj_lambda2;
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}
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pub fn writeback_impulses(&self, manifolds_all: &mut [&mut ContactManifold]) {
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let manifold = &mut manifolds_all[self.manifold_id];
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let k_base = self.manifold_contact_id;
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for k in 0..self.num_contacts as usize {
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let active_contacts = &mut manifold.points[..manifold.data.num_active_contacts()];
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active_contacts[k_base + k].data.impulse = self.elements[k].normal_part.impulse;
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#[cfg(feature = "dim2")]
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{
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active_contacts[k_base + k].data.tangent_impulse =
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self.elements[k].tangent_part[0].impulse;
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}
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#[cfg(feature = "dim3")]
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{
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active_contacts[k_base + k].data.tangent_impulse = [
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self.elements[k].tangent_part[0].impulse,
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self.elements[k].tangent_part[1].impulse,
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];
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}
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}
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}
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}
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