First public release of Rapier.

2020-08-25 22:10:25 +02:00
commit 754a48b7ff
175 changed files with 32819 additions and 0 deletions
--- a/src/dynamics/solver/velocity_constraint.rs
+++ b/src/dynamics/solver/velocity_constraint.rs
@@ -0,0 +1,401 @@
+use super::DeltaVel;
+use crate::dynamics::solver::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::{AngVector, Vector, DIM, MAX_MANIFOLD_POINTS};
+use crate::utils::{WAngularInertia, WBasis, WCross, WDot};
+use simba::simd::SimdPartialOrd;
+
+//#[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),
+    #[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 warmstart(&self, mj_lambdas: &mut [DeltaVel<f32>]) {
+        match self {
+            AnyVelocityConstraint::NongroupedGround(c) => c.warmstart(mj_lambdas),
+            AnyVelocityConstraint::Nongrouped(c) => c.warmstart(mj_lambdas),
+            #[cfg(feature = "simd-is-enabled")]
+            AnyVelocityConstraint::GroupedGround(c) => c.warmstart(mj_lambdas),
+            #[cfg(feature = "simd-is-enabled")]
+            AnyVelocityConstraint::Grouped(c) => c.warmstart(mj_lambdas),
+            AnyVelocityConstraint::Empty => unreachable!(),
+        }
+    }
+
+    pub fn solve(&mut self, mj_lambdas: &mut [DeltaVel<f32>]) {
+        match self {
+            AnyVelocityConstraint::NongroupedGround(c) => c.solve(mj_lambdas),
+            AnyVelocityConstraint::Nongrouped(c) => c.solve(mj_lambdas),
+            #[cfg(feature = "simd-is-enabled")]
+            AnyVelocityConstraint::GroupedGround(c) => c.solve(mj_lambdas),
+            #[cfg(feature = "simd-is-enabled")]
+            AnyVelocityConstraint::Grouped(c) => c.solve(mj_lambdas),
+            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::Empty => unreachable!(),
+        }
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+pub(crate) struct VelocityConstraintElementPart {
+    pub gcross1: AngVector<f32>,
+    pub gcross2: AngVector<f32>,
+    pub rhs: f32,
+    pub impulse: f32,
+    pub r: f32,
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+impl VelocityConstraintElementPart {
+    fn zero() -> Self {
+        Self {
+            gcross1: na::zero(),
+            gcross2: na::zero(),
+            rhs: 0.0,
+            impulse: 0.0,
+            r: 0.0,
+        }
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+pub(crate) struct VelocityConstraintElement {
+    pub normal_part: VelocityConstraintElementPart,
+    pub tangent_part: [VelocityConstraintElementPart; DIM - 1],
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+impl VelocityConstraintElement {
+    pub fn zero() -> Self {
+        Self {
+            normal_part: VelocityConstraintElementPart::zero(),
+            tangent_part: [VelocityConstraintElementPart::zero(); DIM - 1],
+        }
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+pub(crate) struct VelocityConstraint {
+    pub dir1: Vector<f32>, // Non-penetration force direction for the first body.
+    pub im1: f32,
+    pub im2: f32,
+    pub limit: f32,
+    pub mj_lambda1: usize,
+    pub mj_lambda2: usize,
+    pub manifold_id: ContactManifoldIndex,
+    pub manifold_contact_id: usize,
+    pub num_contacts: u8,
+    pub elements: [VelocityConstraintElement; MAX_MANIFOLD_POINTS],
+}
+
+impl VelocityConstraint {
+    #[cfg(feature = "parallel")]
+    pub fn num_active_constraints(manifold: &ContactManifold) -> usize {
+        let rest = manifold.num_active_contacts() % MAX_MANIFOLD_POINTS != 0;
+        manifold.num_active_contacts() / MAX_MANIFOLD_POINTS + rest as usize
+    }
+
+    pub fn generate(
+        params: &IntegrationParameters,
+        manifold_id: ContactManifoldIndex,
+        manifold: &ContactManifold,
+        bodies: &RigidBodySet,
+        out_constraints: &mut Vec<AnyVelocityConstraint>,
+        push: bool,
+    ) {
+        let rb1 = &bodies[manifold.body_pair.body1];
+        let rb2 = &bodies[manifold.body_pair.body2];
+        let mj_lambda1 = rb1.active_set_offset;
+        let mj_lambda2 = rb2.active_set_offset;
+        let force_dir1 = rb1.position * (-manifold.local_n1);
+        let warmstart_coeff = manifold.warmstart_multiplier * params.warmstart_coeff;
+
+        for (l, manifold_points) in manifold
+            .active_contacts()
+            .chunks(MAX_MANIFOLD_POINTS)
+            .enumerate()
+        {
+            #[cfg(not(target_arch = "wasm32"))]
+            let mut constraint = VelocityConstraint {
+                dir1: force_dir1,
+                elements: [VelocityConstraintElement::zero(); MAX_MANIFOLD_POINTS],
+                im1: rb1.mass_properties.inv_mass,
+                im2: rb2.mass_properties.inv_mass,
+                limit: manifold.friction,
+                mj_lambda1,
+                mj_lambda2,
+                manifold_id,
+                manifold_contact_id: l * 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: 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 push {
+                let new_len = out_constraints.len() + 1;
+                unsafe {
+                    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;
+                constraint.im1 = rb1.mass_properties.inv_mass;
+                constraint.im2 = rb2.mass_properties.inv_mass;
+                constraint.limit = manifold.friction;
+                constraint.mj_lambda1 = mj_lambda1;
+                constraint.mj_lambda2 = mj_lambda2;
+                constraint.manifold_id = manifold_id;
+                constraint.manifold_contact_id = l * 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 = (rb1.position * manifold_point.local_p1).coords
+                    - rb1.position.translation.vector;
+                let dp2 = (rb2.position * manifold_point.local_p2).coords
+                    - rb2.position.translation.vector;
+
+                let vel1 = rb1.linvel + rb1.angvel.gcross(dp1);
+                let vel2 = rb2.linvel + rb2.angvel.gcross(dp2);
+
+                // Normal part.
+                {
+                    let gcross1 = rb1
+                        .world_inv_inertia_sqrt
+                        .transform_vector(dp1.gcross(force_dir1));
+                    let gcross2 = rb2
+                        .world_inv_inertia_sqrt
+                        .transform_vector(dp2.gcross(-force_dir1));
+
+                    let r = 1.0
+                        / (rb1.mass_properties.inv_mass
+                            + rb2.mass_properties.inv_mass
+                            + gcross1.gdot(gcross1)
+                            + gcross2.gdot(gcross2));
+
+                    let rhs = (vel1 - vel2).dot(&force_dir1)
+                        + manifold_point.dist.max(0.0) * params.inv_dt();
+
+                    let impulse = manifold_points[k].impulse * warmstart_coeff;
+
+                    constraint.elements[k].normal_part = VelocityConstraintElementPart {
+                        gcross1,
+                        gcross2,
+                        rhs,
+                        impulse,
+                        r,
+                    };
+                }
+
+                // Tangent parts.
+                {
+                    let tangents1 = force_dir1.orthonormal_basis();
+
+                    for j in 0..DIM - 1 {
+                        let gcross1 = rb1
+                            .world_inv_inertia_sqrt
+                            .transform_vector(dp1.gcross(tangents1[j]));
+                        let gcross2 = rb2
+                            .world_inv_inertia_sqrt
+                            .transform_vector(dp2.gcross(-tangents1[j]));
+                        let r = 1.0
+                            / (rb1.mass_properties.inv_mass
+                                + rb2.mass_properties.inv_mass
+                                + gcross1.gdot(gcross1)
+                                + gcross2.gdot(gcross2));
+                        let rhs = (vel1 - vel2).dot(&tangents1[j]);
+                        #[cfg(feature = "dim2")]
+                        let impulse = manifold_points[k].tangent_impulse * warmstart_coeff;
+                        #[cfg(feature = "dim3")]
+                        let impulse = manifold_points[k].tangent_impulse[j] * warmstart_coeff;
+
+                        constraint.elements[k].tangent_part[j] = VelocityConstraintElementPart {
+                            gcross1,
+                            gcross2,
+                            rhs,
+                            impulse,
+                            r,
+                        };
+                    }
+                }
+            }
+
+            #[cfg(not(target_arch = "wasm32"))]
+            if push {
+                out_constraints.push(AnyVelocityConstraint::Nongrouped(constraint));
+            } else {
+                out_constraints[manifold.constraint_index + l] =
+                    AnyVelocityConstraint::Nongrouped(constraint);
+            }
+        }
+    }
+
+    pub fn warmstart(&self, mj_lambdas: &mut [DeltaVel<f32>]) {
+        let mut mj_lambda1 = DeltaVel::zero();
+        let mut mj_lambda2 = DeltaVel::zero();
+
+        for i in 0..self.num_contacts as usize {
+            let elt = &self.elements[i].normal_part;
+            mj_lambda1.linear += self.dir1 * (self.im1 * elt.impulse);
+            mj_lambda1.angular += elt.gcross1 * elt.impulse;
+
+            mj_lambda2.linear += self.dir1 * (-self.im2 * elt.impulse);
+            mj_lambda2.angular += elt.gcross2 * elt.impulse;
+
+            // FIXME: move this out of the for loop?
+            let tangents1 = self.dir1.orthonormal_basis();
+
+            for j in 0..DIM - 1 {
+                let elt = &self.elements[i].tangent_part[j];
+                mj_lambda1.linear += tangents1[j] * (self.im1 * elt.impulse);
+                mj_lambda1.angular += elt.gcross1 * elt.impulse;
+
+                mj_lambda2.linear += tangents1[j] * (-self.im2 * elt.impulse);
+                mj_lambda2.angular += elt.gcross2 * elt.impulse;
+            }
+        }
+
+        mj_lambdas[self.mj_lambda1 as usize].linear += mj_lambda1.linear;
+        mj_lambdas[self.mj_lambda1 as usize].angular += mj_lambda1.angular;
+        mj_lambdas[self.mj_lambda2 as usize].linear += mj_lambda2.linear;
+        mj_lambdas[self.mj_lambda2 as usize].angular += mj_lambda2.angular;
+    }
+
+    pub fn solve(&mut self, mj_lambdas: &mut [DeltaVel<f32>]) {
+        let mut mj_lambda1 = mj_lambdas[self.mj_lambda1 as usize];
+        let mut mj_lambda2 = mj_lambdas[self.mj_lambda2 as usize];
+
+        // Solve friction.
+        for i in 0..self.num_contacts as usize {
+            let tangents1 = self.dir1.orthonormal_basis();
+
+            for j in 0..DIM - 1 {
+                let normal_elt = &self.elements[i].normal_part;
+                let elt = &mut self.elements[i].tangent_part[j];
+                let dimpulse = tangents1[j].dot(&mj_lambda1.linear)
+                    + elt.gcross1.gdot(mj_lambda1.angular)
+                    - 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_lambda1.linear += tangents1[j] * (self.im1 * dlambda);
+                mj_lambda1.angular += elt.gcross1 * dlambda;
+
+                mj_lambda2.linear += tangents1[j] * (-self.im2 * dlambda);
+                mj_lambda2.angular += elt.gcross2 * dlambda;
+            }
+        }
+
+        // Solve penetration.
+        for i in 0..self.num_contacts as usize {
+            let elt = &mut self.elements[i].normal_part;
+            let dimpulse = self.dir1.dot(&mj_lambda1.linear) + elt.gcross1.gdot(mj_lambda1.angular)
+                - self.dir1.dot(&mj_lambda2.linear)
+                + elt.gcross2.gdot(mj_lambda2.angular)
+                + elt.rhs;
+            let new_impulse = (elt.impulse - elt.r * dimpulse).max(0.0);
+            let dlambda = new_impulse - elt.impulse;
+            elt.impulse = new_impulse;
+
+            mj_lambda1.linear += self.dir1 * (self.im1 * dlambda);
+            mj_lambda1.angular += elt.gcross1 * dlambda;
+
+            mj_lambda2.linear += self.dir1 * (-self.im2 * dlambda);
+            mj_lambda2.angular += elt.gcross2 * dlambda;
+        }
+
+        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];
+        let k_base = self.manifold_contact_id;
+
+        for k in 0..self.num_contacts as usize {
+            let active_contacts = manifold.active_contacts_mut();
+            active_contacts[k_base + k].impulse = self.elements[k].normal_part.impulse;
+            #[cfg(feature = "dim2")]
+            {
+                active_contacts[k_base + k].tangent_impulse =
+                    self.elements[k].tangent_part[0].impulse;
+            }
+            #[cfg(feature = "dim3")]
+            {
+                active_contacts[k_base + k].tangent_impulse = [
+                    self.elements[k].tangent_part[0].impulse,
+                    self.elements[k].tangent_part[1].impulse,
+                ];
+            }
+        }
+    }
+}