Merge pull request #579 from dimforge/joints-improvements

Feat: implement a "small-steps" velocity-based constraints solver + joint improvements

1 files changed, 0 insertions, 441 deletions

diff --git a/src/dynamics/solver/velocity_constraint.rs b/src/dynamics/solver/velocity_constraint.rs
deleted file mode 100644
index a6b7384..0000000
--- a/src/dynamics/solver/velocity_constraint.rs
+++ /dev/null
@@ -1,441 +0,0 @@
-use crate::dynamics::solver::{
-    GenericVelocityConstraint, GenericVelocityGroundConstraint, VelocityGroundConstraint,
-};
-#[cfg(feature = "simd-is-enabled")]
-use crate::dynamics::solver::{WVelocityConstraint, WVelocityGroundConstraint};
-use crate::dynamics::{IntegrationParameters, RigidBodySet};
-use crate::geometry::{ContactManifold, ContactManifoldIndex};
-use crate::math::{Real, Vector, DIM, MAX_MANIFOLD_POINTS};
-use crate::utils::{self, WAngularInertia, WBasis, WCross, WDot};
-use na::DVector;
-
-use super::{DeltaVel, VelocityConstraintElement, VelocityConstraintNormalPart};
-
-//#[repr(align(64))]
-#[derive(Copy, Clone, Debug)]
-pub(crate) enum AnyVelocityConstraint {
-    NongroupedGround(VelocityGroundConstraint),
-    Nongrouped(VelocityConstraint),
-    #[cfg(feature = "simd-is-enabled")]
-    GroupedGround(WVelocityGroundConstraint),
-    #[cfg(feature = "simd-is-enabled")]
-    Grouped(WVelocityConstraint),
-    NongroupedGenericGround(GenericVelocityGroundConstraint),
-    NongroupedGeneric(GenericVelocityConstraint),
-    #[allow(dead_code)] // The Empty variant is only used with parallel code.
-    Empty,
-}
-
-impl AnyVelocityConstraint {
-    #[cfg(target_arch = "wasm32")]
-    pub fn as_nongrouped_mut(&mut self) -> Option<&mut VelocityConstraint> {
-        if let AnyVelocityConstraint::Nongrouped(c) = self {
-            Some(c)
-        } else {
-            None
-        }
-    }
-
-    #[cfg(target_arch = "wasm32")]
-    pub fn as_nongrouped_ground_mut(&mut self) -> Option<&mut VelocityGroundConstraint> {
-        if let AnyVelocityConstraint::NongroupedGround(c) = self {
-            Some(c)
-        } else {
-            None
-        }
-    }
-
-    pub fn remove_bias_from_rhs(&mut self) {
-        match self {
-            AnyVelocityConstraint::Nongrouped(c) => c.remove_cfm_and_bias_from_rhs(),
-            AnyVelocityConstraint::NongroupedGround(c) => c.remove_cfm_and_bias_from_rhs(),
-            #[cfg(feature = "simd-is-enabled")]
-            AnyVelocityConstraint::Grouped(c) => c.remove_cfm_and_bias_from_rhs(),
-            #[cfg(feature = "simd-is-enabled")]
-            AnyVelocityConstraint::GroupedGround(c) => c.remove_cfm_and_bias_from_rhs(),
-            AnyVelocityConstraint::NongroupedGeneric(c) => c.remove_cfm_and_bias_from_rhs(),
-            AnyVelocityConstraint::NongroupedGenericGround(c) => c.remove_cfm_and_bias_from_rhs(),
-            AnyVelocityConstraint::Empty => unreachable!(),
-        }
-    }
-
-    pub fn solve(
-        &mut self,
-        jacobians: &DVector<Real>,
-        mj_lambdas: &mut [DeltaVel<Real>],
-        generic_mj_lambdas: &mut DVector<Real>,
-        solve_restitution: bool,
-        solve_friction: bool,
-    ) {
-        match self {
-            AnyVelocityConstraint::NongroupedGround(c) => {
-                c.solve(mj_lambdas, solve_restitution, solve_friction)
-            }
-            AnyVelocityConstraint::Nongrouped(c) => {
-                c.solve(mj_lambdas, solve_restitution, solve_friction)
-            }
-            #[cfg(feature = "simd-is-enabled")]
-            AnyVelocityConstraint::GroupedGround(c) => {
-                c.solve(mj_lambdas, solve_restitution, solve_friction)
-            }
-            #[cfg(feature = "simd-is-enabled")]
-            AnyVelocityConstraint::Grouped(c) => {
-                c.solve(mj_lambdas, solve_restitution, solve_friction)
-            }
-            AnyVelocityConstraint::NongroupedGeneric(c) => c.solve(
-                jacobians,
-                mj_lambdas,
-                generic_mj_lambdas,
-                solve_restitution,
-                solve_friction,
-            ),
-            AnyVelocityConstraint::NongroupedGenericGround(c) => c.solve(
-                jacobians,
-                generic_mj_lambdas,
-                solve_restitution,
-                solve_friction,
-            ),
-            AnyVelocityConstraint::Empty => unreachable!(),
-        }
-    }
-
-    pub fn writeback_impulses(&self, manifold_all: &mut [&mut ContactManifold]) {
-        match self {
-            AnyVelocityConstraint::NongroupedGround(c) => c.writeback_impulses(manifold_all),
-            AnyVelocityConstraint::Nongrouped(c) => c.writeback_impulses(manifold_all),
-            #[cfg(feature = "simd-is-enabled")]
-            AnyVelocityConstraint::GroupedGround(c) => c.writeback_impulses(manifold_all),
-            #[cfg(feature = "simd-is-enabled")]
-            AnyVelocityConstraint::Grouped(c) => c.writeback_impulses(manifold_all),
-            AnyVelocityConstraint::NongroupedGeneric(c) => c.writeback_impulses(manifold_all),
-            AnyVelocityConstraint::NongroupedGenericGround(c) => c.writeback_impulses(manifold_all),
-            AnyVelocityConstraint::Empty => unreachable!(),
-        }
-    }
-}
-
-#[derive(Copy, Clone, Debug)]
-pub(crate) struct VelocityConstraint {
-    pub dir1: Vector<Real>, // Non-penetration force direction for the first body.
-    #[cfg(feature = "dim3")]
-    pub tangent1: Vector<Real>, // One of the friction force directions.
-    pub im1: Vector<Real>,
-    pub im2: Vector<Real>,
-    pub cfm_factor: Real,
-    pub limit: Real,
-    pub mj_lambda1: usize,
-    pub mj_lambda2: usize,
-    pub manifold_id: ContactManifoldIndex,
-    pub manifold_contact_id: [u8; MAX_MANIFOLD_POINTS],
-    pub num_contacts: u8,
-    pub elements: [VelocityConstraintElement<Real>; MAX_MANIFOLD_POINTS],
-}
-
-impl VelocityConstraint {
-    #[cfg(feature = "parallel")]
-    pub fn num_active_constraints_and_jacobian_lines(manifold: &ContactManifold) -> (usize, usize) {
-        let rest = manifold.data.solver_contacts.len() % MAX_MANIFOLD_POINTS != 0;
-        (
-            manifold.data.solver_contacts.len() / MAX_MANIFOLD_POINTS + rest as usize,
-            manifold.data.solver_contacts.len() * DIM,
-        )
-    }
-
-    pub fn generate(
-        params: &IntegrationParameters,
-        manifold_id: ContactManifoldIndex,
-        manifold: &ContactManifold,
-        bodies: &RigidBodySet,
-        out_constraints: &mut Vec<AnyVelocityConstraint>,
-        insert_at: Option<usize>,
-    ) {
-        assert_eq!(manifold.data.relative_dominance, 0);
-
-        let cfm_factor = params.cfm_factor();
-        let inv_dt = params.inv_dt();
-        let erp_inv_dt = params.erp_inv_dt();
-
-        let handle1 = manifold.data.rigid_body1.unwrap();
-        let handle2 = manifold.data.rigid_body2.unwrap();
-
-        let rb1 = &bodies[handle1];
-        let (vels1, mprops1) = (&rb1.vels, &rb1.mprops);
-        let rb2 = &bodies[handle2];
-        let (vels2, mprops2) = (&rb2.vels, &rb2.mprops);
-        let ccd_thickness = rb1.ccd.ccd_thickness + rb2.ccd.ccd_thickness;
-
-        let mj_lambda1 = rb1.ids.active_set_offset;
-        let mj_lambda2 = rb2.ids.active_set_offset;
-        let force_dir1 = -manifold.data.normal;
-
-        #[cfg(feature = "dim2")]
-        let tangents1 = force_dir1.orthonormal_basis();
-        #[cfg(feature = "dim3")]
-        let tangents1 =
-            super::compute_tangent_contact_directions(&force_dir1, &vels1.linvel, &vels2.linvel);
-
-        for (_l, manifold_points) in manifold
-            .data
-            .solver_contacts
-            .chunks(MAX_MANIFOLD_POINTS)
-            .enumerate()
-        {
-            let mut is_fast_contact = false;
-
-            #[cfg(not(target_arch = "wasm32"))]
-            let mut constraint = VelocityConstraint {
-                dir1: force_dir1,
-                #[cfg(feature = "dim3")]
-                tangent1: tangents1[0],
-                elements: [VelocityConstraintElement::zero(); MAX_MANIFOLD_POINTS],
-                im1: mprops1.effective_inv_mass,
-                im2: mprops2.effective_inv_mass,
-                cfm_factor,
-                limit: 0.0,
-                mj_lambda1,
-                mj_lambda2,
-                manifold_id,
-                manifold_contact_id: [0; MAX_MANIFOLD_POINTS],
-                num_contacts: manifold_points.len() as u8,
-            };
-
-            // TODO: this is a WIP optimization for WASM platforms.
-            // For some reasons, the compiler does not inline the `Vec::push` method
-            // in this method. This generates two memset and one memcpy which are both very
-            // expansive.
-            // This would likely be solved by some kind of "placement-push" (like emplace in C++).
-            // In the mean time, a workaround is to "push" using `.resize_with` and `::uninit()` to
-            // avoid spurious copying.
-            // Is this optimization beneficial when targeting non-WASM platforms?
-            //
-            // NOTE: impulse_joints have the same problem, but it is not easy to refactor the code that way
-            // for the moment.
-            #[cfg(target_arch = "wasm32")]
-            let constraint = if insert_at.is_none() {
-                let new_len = out_constraints.len() + 1;
-                unsafe {
-                    #[allow(invalid_value)]
-                    out_constraints.resize_with(new_len, || {
-                        AnyVelocityConstraint::Nongrouped(
-                            std::mem::MaybeUninit::uninit().assume_init(),
-                        )
-                    });
-                }
-                out_constraints
-                    .last_mut()
-                    .unwrap()
-                    .as_nongrouped_mut()
-                    .unwrap()
-            } else {
-                unreachable!(); // We don't have parallelization on WASM yet, so this is unreachable.
-            };
-
-            #[cfg(target_arch = "wasm32")]
-            {
-                constraint.dir1 = force_dir1;
-                #[cfg(feature = "dim3")]
-                {
-                    constraint.tangent1 = tangents1[0];
-                }
-                constraint.im1 = mprops1.effective_inv_mass;
-                constraint.im2 = mprops2.effective_inv_mass;
-                constraint.cfm_factor = cfm_factor;
-                constraint.limit = 0.0;
-                constraint.mj_lambda1 = mj_lambda1;
-                constraint.mj_lambda2 = mj_lambda2;
-                constraint.manifold_id = manifold_id;
-                constraint.manifold_contact_id = [0; MAX_MANIFOLD_POINTS];
-                constraint.num_contacts = manifold_points.len() as u8;
-            }
-
-            for k in 0..manifold_points.len() {
-                let manifold_point = &manifold_points[k];
-                let dp1 = manifold_point.point - mprops1.world_com;
-                let dp2 = manifold_point.point - mprops2.world_com;
-
-                let vel1 = vels1.linvel + vels1.angvel.gcross(dp1);
-                let vel2 = vels2.linvel + vels2.angvel.gcross(dp2);
-
-                constraint.limit = manifold_point.friction;
-                constraint.manifold_contact_id[k] = manifold_point.contact_id;
-
-                // Normal part.
-                {
-                    let gcross1 = mprops1
-                        .effective_world_inv_inertia_sqrt
-                        .transform_vector(dp1.gcross(force_dir1));
-                    let gcross2 = mprops2
-                        .effective_world_inv_inertia_sqrt
-                        .transform_vector(dp2.gcross(-force_dir1));
-
-                    let imsum = mprops1.effective_inv_mass + mprops2.effective_inv_mass;
-                    let projected_mass = utils::inv(
-                        force_dir1.dot(&imsum.component_mul(&force_dir1))
-                            + gcross1.gdot(gcross1)
-                            + gcross2.gdot(gcross2),
-                    );
-
-                    let is_bouncy = manifold_point.is_bouncy() as u32 as Real;
-                    let is_resting = 1.0 - is_bouncy;
-
-                    let mut rhs_wo_bias = (1.0 + is_bouncy * manifold_point.restitution)
-                        * (vel1 - vel2).dot(&force_dir1);
-                    rhs_wo_bias += manifold_point.dist.max(0.0) * inv_dt;
-                    rhs_wo_bias *= is_bouncy + is_resting;
-                    let rhs_bias = /* is_resting
-                        * */  erp_inv_dt
-                        * (manifold_point.dist + params.allowed_linear_error).clamp(-params.max_penetration_correction, 0.0);
-
-                    let rhs = rhs_wo_bias + rhs_bias;
-                    is_fast_contact = is_fast_contact || (-rhs * params.dt > ccd_thickness * 0.5);
-
-                    constraint.elements[k].normal_part = VelocityConstraintNormalPart {
-                        gcross1,
-                        gcross2,
-                        rhs,
-                        rhs_wo_bias,
-                        impulse: na::zero(),
-                        r: projected_mass,
-                    };
-                }
-
-                // Tangent parts.
-                {
-                    constraint.elements[k].tangent_part.impulse = na::zero();
-
-                    for j in 0..DIM - 1 {
-                        let gcross1 = mprops1
-                            .effective_world_inv_inertia_sqrt
-                            .transform_vector(dp1.gcross(tangents1[j]));
-                        let gcross2 = mprops2
-                            .effective_world_inv_inertia_sqrt
-                            .transform_vector(dp2.gcross(-tangents1[j]));
-                        let imsum = mprops1.effective_inv_mass + mprops2.effective_inv_mass;
-                        let r = tangents1[j].dot(&imsum.component_mul(&tangents1[j]))
-                            + gcross1.gdot(gcross1)
-                            + gcross2.gdot(gcross2);
-                        let rhs =
-                            (vel1 - vel2 + manifold_point.tangent_velocity).dot(&tangents1[j]);
-
-                        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] = if cfg!(feature = "dim2") {
-                            utils::inv(r)
-                        } else {
-                            r
-                        };
-                    }
-
-                    #[cfg(feature = "dim3")]
-                    {
-                        constraint.elements[k].tangent_part.r[2] = 2.0
-                            * (constraint.elements[k].tangent_part.gcross1[0]
-                                .gdot(constraint.elements[k].tangent_part.gcross1[1])
-                                + constraint.elements[k].tangent_part.gcross2[0]
-                                    .gdot(constraint.elements[k].tangent_part.gcross2[1]));
-                    }
-                }
-            }
-
-            constraint.cfm_factor = if is_fast_contact { 1.0 } else { cfm_factor };
-
-            #[cfg(not(target_arch = "wasm32"))]
-            if let Some(at) = insert_at {
-                out_constraints[at + _l] = AnyVelocityConstraint::Nongrouped(constraint);
-            } else {
-                out_constraints.push(AnyVelocityConstraint::Nongrouped(constraint));
-            }
-        }
-    }
-
-    pub fn solve(
-        &mut self,
-        mj_lambdas: &mut [DeltaVel<Real>],
-        solve_normal: bool,
-        solve_friction: bool,
-    ) {
-        let mut mj_lambda1 = mj_lambdas[self.mj_lambda1 as usize];
-        let mut mj_lambda2 = mj_lambdas[self.mj_lambda2 as usize];
-
-        VelocityConstraintElement::solve_group(
-            self.cfm_factor,
-            &mut self.elements[..self.num_contacts as usize],
-            &self.dir1,
-            #[cfg(feature = "dim3")]
-            &self.tangent1,
-            &self.im1,
-            &self.im2,
-            self.limit,
-            &mut mj_lambda1,
-            &mut mj_lambda2,
-            solve_normal,
-            solve_friction,
-        );
-
-        mj_lambdas[self.mj_lambda1 as usize] = mj_lambda1;
-        mj_lambdas[self.mj_lambda2 as usize] = mj_lambda2;
-    }
-
-    pub fn writeback_impulses(&self, manifolds_all: &mut [&mut ContactManifold]) {
-        let manifold = &mut manifolds_all[self.manifold_id];
-
-        for k in 0..self.num_contacts as usize {
-            let contact_id = self.manifold_contact_id[k];
-            let active_contact = &mut manifold.points[contact_id as usize];
-            active_contact.data.impulse = self.elements[k].normal_part.impulse;
-
-            #[cfg(feature = "dim2")]
-            {
-                active_contact.data.tangent_impulse = self.elements[k].tangent_part.impulse[0];
-            }
-            #[cfg(feature = "dim3")]
-            {
-                active_contact.data.tangent_impulse = self.elements[k].tangent_part.impulse;
-            }
-        }
-    }
-
-    pub fn remove_cfm_and_bias_from_rhs(&mut self) {
-        self.cfm_factor = 1.0;
-        for elt in &mut self.elements {
-            elt.normal_part.rhs = elt.normal_part.rhs_wo_bias;
-        }
-    }
-}
-
-#[inline(always)]
-#[cfg(feature = "dim3")]
-pub(crate) fn compute_tangent_contact_directions<N>(
-    force_dir1: &Vector<N>,
-    linvel1: &Vector<N>,
-    linvel2: &Vector<N>,
-) -> [Vector<N>; DIM - 1]
-where
-    N: utils::WReal,
-    Vector<N>: WBasis,
-{
-    use na::SimdValue;
-
-    // Compute the tangent direction. Pick the direction of
-    // the linear relative velocity, if it is not too small.
-    // Otherwise use a fallback direction.
-    let relative_linvel = linvel1 - linvel2;
-    let mut tangent_relative_linvel =
-        relative_linvel - force_dir1 * (force_dir1.dot(&relative_linvel));
-
-    let tangent_linvel_norm = {
-        let _disable_fe_except =
-            crate::utils::DisableFloatingPointExceptionsFlags::disable_floating_point_exceptions();
-        tangent_relative_linvel.normalize_mut()
-    };
-
-    const THRESHOLD: Real = 1.0e-4;
-    let use_fallback = tangent_linvel_norm.simd_lt(N::splat(THRESHOLD));
-    let tangent_fallback = force_dir1.orthonormal_vector();
-
-    let tangent1 = tangent_fallback.select(use_fallback, tangent_relative_linvel);
-    let bitangent1 = force_dir1.cross(&tangent1);
-
-    [tangent1, bitangent1]
-}