Complete the implementation of non-simd joint motor for the revolute joint.

src/dynamics/joint/generic_joint.rs

@@ -54,6 +54,13 @@ impl GenericJoint {
         }
     }
 
+    pub fn set_dof_vel(&mut self, dof: u8, target_vel: Real, max_force: Real) {
+        self.min_velocity[dof as usize] = target_vel;
+        self.max_velocity[dof as usize] = target_vel;
+        self.min_impulse[dof as usize] = -max_force;
+        self.max_impulse[dof as usize] = max_force;
+    }
+
     pub fn free_dof(&mut self, dof: u8) {
         self.min_position[dof as usize] = -Real::MAX;
         self.max_position[dof as usize] = Real::MAX;
@@ -82,6 +89,18 @@ impl From<RevoluteJoint> for GenericJoint {
 
         let mut result = Self::new(local_anchor1, local_anchor2);
         result.free_dof(3);
+
+        if joint.motor_damping != 0.0 {
+            result.set_dof_vel(3, joint.motor_target_vel, joint.motor_max_impulse);
+        }
+
+        result.impulse[0] = joint.impulse[0];
+        result.impulse[1] = joint.impulse[1];
+        result.impulse[2] = joint.impulse[2];
+        result.impulse[3] = joint.motor_impulse;
+        result.impulse[4] = joint.impulse[3];
+        result.impulse[5] = joint.impulse[4];
+
         result
     }
 }
@@ -92,6 +111,9 @@ impl From<BallJoint> for GenericJoint {
         let local_anchor2 = Isometry::new(joint.local_anchor2.coords, na::zero());
 
         let mut result = Self::new(local_anchor1, local_anchor2);
+        result.impulse[0] = joint.impulse[0];
+        result.impulse[1] = joint.impulse[1];
+        result.impulse[2] = joint.impulse[2];
         result.free_dof(3);
         result.free_dof(4);
         result.free_dof(5);

src/dynamics/joint/joint.rs

@@ -1,8 +1,6 @@
 #[cfg(feature = "dim3")]
 use crate::dynamics::RevoluteJoint;
-use crate::dynamics::{
+use crate::dynamics::{BallJoint, FixedJoint, JointHandle, PrismaticJoint, RigidBodyHandle};
-    BallJoint, FixedJoint, GenericJoint, JointHandle, PrismaticJoint, RigidBodyHandle,
-};
 
 #[derive(Copy, Clone)]
 #[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
@@ -19,7 +17,7 @@ pub enum JointParams {
     /// A revolute joint that removes all degrees of degrees of freedom between the affected
     /// bodies except for the translation along one axis.
     RevoluteJoint(RevoluteJoint),
-    GenericJoint(GenericJoint),
+    // GenericJoint(GenericJoint),
 }
 
 impl JointParams {
@@ -29,7 +27,7 @@ impl JointParams {
             JointParams::BallJoint(_) => 0,
             JointParams::FixedJoint(_) => 1,
             JointParams::PrismaticJoint(_) => 2,
-            JointParams::GenericJoint(_) => 3,
+            // JointParams::GenericJoint(_) => 3,
             #[cfg(feature = "dim3")]
             JointParams::RevoluteJoint(_) => 4,
         }
@@ -53,14 +51,14 @@ impl JointParams {
         }
     }
 
-    /// Gets a reference to the underlying generic joint, if `self` is one.
+    // /// Gets a reference to the underlying generic joint, if `self` is one.
-    pub fn as_generic_joint(&self) -> Option<&GenericJoint> {
+    // pub fn as_generic_joint(&self) -> Option<&GenericJoint> {
-        if let JointParams::GenericJoint(j) = self {
+    //     if let JointParams::GenericJoint(j) = self {
-            Some(j)
+    //         Some(j)
-        } else {
+    //     } else {
-            None
+    //         None
-        }
+    //     }
-    }
+    // }
 
     /// Gets a reference to the underlying prismatic joint, if `self` is one.
     pub fn as_prismatic_joint(&self) -> Option<&PrismaticJoint> {
@@ -94,11 +92,11 @@ impl From<FixedJoint> for JointParams {
     }
 }
 
-impl From<GenericJoint> for JointParams {
+// impl From<GenericJoint> for JointParams {
-    fn from(j: GenericJoint) -> Self {
+//     fn from(j: GenericJoint) -> Self {
-        JointParams::GenericJoint(j)
+//         JointParams::GenericJoint(j)
-    }
+//     }
-}
+// }
 
 #[cfg(feature = "dim3")]
 impl From<RevoluteJoint> for JointParams {

src/dynamics/joint/mod.rs

@@ -1,18 +1,20 @@
 pub use self::ball_joint::BallJoint;
 pub use self::fixed_joint::FixedJoint;
-pub use self::generic_joint::GenericJoint;
+// pub use self::generic_joint::GenericJoint;
 pub use self::joint::{Joint, JointParams};
 pub(crate) use self::joint_set::{JointGraphEdge, JointIndex};
 pub use self::joint_set::{JointHandle, JointSet};
 pub use self::prismatic_joint::PrismaticJoint;
 #[cfg(feature = "dim3")]
 pub use self::revolute_joint::RevoluteJoint;
+pub use self::spring_model::SpringModel;
 
 mod ball_joint;
 mod fixed_joint;
-mod generic_joint;
+// mod generic_joint;
 mod joint;
 mod joint_set;
 mod prismatic_joint;
 #[cfg(feature = "dim3")]
 mod revolute_joint;
+mod spring_model;

src/dynamics/joint/revolute_joint.rs

@@ -1,6 +1,7 @@
-use crate::math::{Point, Real, Vector};
+use crate::dynamics::SpringModel;
+use crate::math::{Isometry, Point, Real, Vector};
 use crate::utils::WBasis;
-use na::{Unit, Vector5};
+use na::{RealField, Unit, Vector5};
 
 #[derive(Copy, Clone)]
 #[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
@@ -22,6 +23,28 @@ pub struct RevoluteJoint {
     ///
     /// The impulse applied to the second body is given by `-impulse`.
     pub impulse: Vector5<Real>,
+    /// The target relative angular velocity the motor will attempt to reach.
+    pub motor_target_vel: Real,
+    /// The target relative angle along the joint axis the motor will attempt to reach.
+    pub motor_target_pos: Real,
+    /// The motor's stiffness.
+    /// See the documentation of `SpringModel` for more information on this parameter.
+    pub motor_stiffness: Real,
+    /// The motor's damping.
+    /// See the documentation of `SpringModel` for more information on this parameter.
+    pub motor_damping: Real,
+    /// The maximal impulse the motor is able to deliver.
+    pub motor_max_impulse: Real,
+    /// The angular impulse applied by the motor.
+    pub motor_impulse: Real,
+    /// The spring-like model used by the motor to reach the target velocity and .
+    pub motor_model: SpringModel,
+    // Used to handle cases where the position target ends up being more than pi radians away.
+    pub(crate) motor_last_angle: Real,
+    // The angular impulse expressed in world-space.
+    pub(crate) world_ang_impulse: Vector<Real>,
+    // The world-space orientation of the free axis of the first attached body.
+    pub(crate) prev_axis1: Vector<Real>,
 }
 
 impl RevoluteJoint {
@@ -41,6 +64,74 @@ impl RevoluteJoint {
             basis1: local_axis1.orthonormal_basis(),
             basis2: local_axis2.orthonormal_basis(),
             impulse: na::zero(),
+            world_ang_impulse: na::zero(),
+            motor_target_vel: 0.0,
+            motor_target_pos: 0.0,
+            motor_stiffness: 0.0,
+            motor_damping: 0.0,
+            motor_max_impulse: Real::MAX,
+            motor_impulse: 0.0,
+            prev_axis1: *local_axis1,
+            motor_model: SpringModel::VelocityBased,
+            motor_last_angle: 0.0,
         }
     }
+
+    pub fn configure_motor_model(&mut self, model: SpringModel) {
+        self.motor_model = model;
+    }
+
+    pub fn configure_motor_velocity(&mut self, target_vel: Real, factor: Real) {
+        self.configure_motor(self.motor_target_pos, target_vel, 0.0, factor)
+    }
+
+    pub fn configure_motor_position(&mut self, target_pos: Real, stiffness: Real, damping: Real) {
+        self.configure_motor(target_pos, 0.0, stiffness, damping)
+    }
+
+    pub fn configure_motor(
+        &mut self,
+        target_pos: Real,
+        target_vel: Real,
+        stiffness: Real,
+        damping: Real,
+    ) {
+        self.motor_target_vel = target_vel;
+        self.motor_target_pos = target_pos;
+        self.motor_stiffness = stiffness;
+        self.motor_damping = damping;
+    }
+
+    /// Estimates the current position of the motor angle.
+    pub fn estimate_motor_angle(
+        &self,
+        body_pos1: &Isometry<Real>,
+        body_pos2: &Isometry<Real>,
+    ) -> Real {
+        let motor_axis1 = body_pos1 * self.local_axis1;
+        let ref1 = body_pos1 * self.basis1[0];
+        let ref2 = body_pos2 * self.basis2[0];
+
+        let last_angle_cycles = (self.motor_last_angle / Real::two_pi()).trunc() * Real::two_pi();
+
+        // Measure the position between 0 and 2-pi
+        let new_angle = if ref1.cross(&ref2).dot(&motor_axis1) < 0.0 {
+            Real::two_pi() - ref1.angle(&ref2)
+        } else {
+            ref1.angle(&ref2)
+        };
+
+        // The last angle between 0 and 2-pi
+        let last_angle_zero_two_pi = self.motor_last_angle - last_angle_cycles;
+
+        // Figure out the smallest angle differance.
+        let mut angle_diff = new_angle - last_angle_zero_two_pi;
+        if angle_diff > Real::pi() {
+            angle_diff -= Real::two_pi()
+        } else if angle_diff < -Real::pi() {
+            angle_diff += Real::two_pi()
+        }
+
+        self.motor_last_angle + angle_diff
+    }
 }

src/dynamics/joint/spring_model.rs

@@ -0,0 +1,59 @@
+use crate::math::Real;
+
+/// The spring-like model used for constraints resolution.
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
+pub enum SpringModel {
+    /// No equation is solved.
+    Disabled,
+    /// The solved spring-like equation is:
+    /// `delta_velocity(t + dt) = stiffness / dt * (target_pos - pos(t)) + damping * (target_vel - vel(t))`
+    ///
+    /// Here the `stiffness` is the ratio of position error to be solved at each timestep (like
+    /// a velocity-based ERP), and the `damping` is the ratio of velocity error to be solved at
+    /// each timestep.
+    VelocityBased,
+    /// The solved spring-like equation is:
+    /// `acceleration(t + dt) = stiffness * (target_pos - pos(t)) + damping * (target_vel - vel(t))`
+    AccelerationBased,
+    /// The solved spring-like equation is:
+    /// `force(t + dt) = stiffness * (target_pos - pos(t + dt)) + damping * (target_vel - vel(t + dt))`
+    ForceBased,
+}
+
+impl SpringModel {
+    /// Combines the coefficients used for solving the spring equation.
+    ///
+    /// Returns the new coefficients (stiffness, damping, inv_lhs_scale, keep_inv_lhs)
+    /// coefficients for the equivalent impulse-based equation. These new
+    /// coefficients must be used in the following way:
+    /// - `rhs = (stiffness * pos_err + damping * vel_err) / gamma`.
+    /// - `new_inv_lhs = gamma * if keep_inv_lhs { inv_lhs } else { 1.0 }`.
+    /// Note that the returned `gamma` will be zero if both `stiffness` and `damping` are zero.
+    pub fn combine_coefficients(
+        self,
+        dt: Real,
+        stiffness: Real,
+        damping: Real,
+    ) -> (Real, Real, Real, bool) {
+        match self {
+            SpringModel::VelocityBased => (stiffness * crate::utils::inv(dt), damping, 1.0, true),
+            SpringModel::AccelerationBased => {
+                let effective_stiffness = stiffness * dt;
+                let effective_damping = damping * dt;
+                // TODO: Using gamma behaves very badly for some reasons.
+                // Maybe I got the formulation wrong, so let's keep it to 1.0 for now,
+                // and get back to this later.
+                // let gamma = effective_stiffness * dt + effective_damping;
+                (effective_stiffness, effective_damping, 1.0, true)
+            }
+            SpringModel::ForceBased => {
+                let effective_stiffness = stiffness * dt;
+                let effective_damping = damping * dt;
+                let gamma = effective_stiffness * dt + effective_damping;
+                (effective_stiffness, effective_damping, gamma, false)
+            }
+            SpringModel::Disabled => return (0.0, 0.0, 0.0, false),
+        }
+    }
+}

src/dynamics/mod.rs

@@ -5,7 +5,14 @@ pub(crate) use self::joint::JointIndex;
 #[cfg(feature = "dim3")]
 pub use self::joint::RevoluteJoint;
 pub use self::joint::{
-    BallJoint, FixedJoint, GenericJoint, Joint, JointHandle, JointParams, JointSet, PrismaticJoint,
+    BallJoint,
+    FixedJoint,
+    Joint,
+    JointHandle,
+    JointParams,
+    JointSet,
+    PrismaticJoint,
+    SpringModel, // GenericJoint
 };
 pub use self::rigid_body::{ActivationStatus, BodyStatus, RigidBody, RigidBodyBuilder};
 pub use self::rigid_body_set::{BodyPair, RigidBodyHandle, RigidBodySet};

src/dynamics/solver/joint_constraint/generic_velocity_constraint.rs

@@ -32,7 +32,8 @@ pub(crate) struct GenericVelocityConstraint {
 
     r1: Vector<Real>,
     r2: Vector<Real>,
-    basis: Rotation<Real>,
+    basis1: Rotation<Real>,
+    basis2: Rotation<Real>,
     dependant_set_mask: SpacialVector<Real>,
 
     vel: GenericConstraintPart,
@@ -44,22 +45,22 @@ impl GenericVelocityConstraint {
         max_velocity: &SpatialVector<Real>,
         r1: &Vector<Real>,
         r2: &Vector<Real>,
-        basis: &Rotation<Real>,
+        basis1: &Rotation<Real>,
+        basis2: &Rotation<Real>,
         rb1: &RigidBody,
         rb2: &RigidBody,
     ) -> SpatialVector<Real> {
-        let lin_dvel = -rb1.linvel - rb1.angvel.gcross(*r1) + rb2.linvel + rb2.angvel.gcross(*r2);
+        let lin_dvel = basis1.inverse_transform_vector(&(-rb1.linvel - rb1.angvel.gcross(*r1)))
-        let ang_dvel = -rb1.angvel + rb2.angvel;
+            + basis2.inverse_transform_vector(&(rb2.linvel + rb2.angvel.gcross(*r2)));
-
+        let ang_dvel = basis1.inverse_transform_vector(&-rb1.angvel)
-        let lin_dvel2 = basis.inverse_transform_vector(&lin_dvel);
+            + basis2.inverse_transform_vector(&rb2.angvel);
-        let ang_dvel2 = basis.inverse_transform_vector(&ang_dvel);
 
         let min_linvel = min_velocity.xyz();
         let min_angvel = min_velocity.fixed_rows::<AngDim>(DIM).into_owned();
         let max_linvel = max_velocity.xyz();
         let max_angvel = max_velocity.fixed_rows::<AngDim>(DIM).into_owned();
-        let lin_rhs = lin_dvel2 - lin_dvel2.sup(&min_linvel).inf(&max_linvel);
+        let lin_rhs = lin_dvel - lin_dvel.sup(&min_linvel).inf(&max_linvel);
-        let ang_rhs = ang_dvel2 - ang_dvel2.sup(&min_angvel).inf(&max_angvel);
+        let ang_rhs = ang_dvel - ang_dvel.sup(&min_angvel).inf(&max_angvel);
 
         #[cfg(feature = "dim2")]
         return Vector3::new(lin_rhs.x, lin_rhs.y, ang_rhs);
@@ -120,6 +121,32 @@ impl GenericVelocityConstraint {
         }
     }
 
+    pub fn invert_partial_delassus_matrix(
+        min_impulse: &Vector<Real>,
+        max_impulse: &Vector<Real>,
+        dependant_set_mask: &mut Vector<Real>,
+        mut delassus: na::Matrix3<Real>,
+    ) -> na::Matrix3<Real> {
+        // Adjust the Delassus matrix to take force limits into account.
+        // If a DoF has a force limit, then we need to make its
+        // constraint independent from the others because otherwise
+        // the force clamping will cause errors to propagate in the
+        // other constraints.
+        for i in 0..3 {
+            if min_impulse[i] > -Real::MAX || max_impulse[i] < Real::MAX {
+                let diag = delassus[(i, i)];
+                delassus.column_mut(i).fill(0.0);
+                delassus.row_mut(i).fill(0.0);
+                delassus[(i, i)] = diag;
+                dependant_set_mask[i] = 0.0;
+            } else {
+                dependant_set_mask[i] = 1.0;
+            }
+        }
+
+        delassus.try_inverse().unwrap()
+    }
+
     pub fn compute_position_error(
         joint: &GenericJoint,
         anchor1: &Isometry<Real>,
@@ -169,32 +196,6 @@ impl GenericVelocityConstraint {
         }
     }
 
-    pub fn invert_partial_delassus_matrix(
-        min_impulse: &Vector<Real>,
-        max_impulse: &Vector<Real>,
-        dependant_set_mask: &mut Vector<Real>,
-        mut delassus: na::Matrix3<Real>,
-    ) -> na::Matrix3<Real> {
-        // Adjust the Delassus matrix to take force limits into account.
-        // If a DoF has a force limit, then we need to make its
-        // constraint independent from the others because otherwise
-        // the force clamping will cause errors to propagate in the
-        // other constraints.
-        for i in 0..3 {
-            if min_impulse[i] > -Real::MAX || max_impulse[i] < Real::MAX {
-                let diag = delassus[(i, i)];
-                delassus.column_mut(i).fill(0.0);
-                delassus.row_mut(i).fill(0.0);
-                delassus[(i, i)] = diag;
-                dependant_set_mask[i] = 0.0;
-            } else {
-                dependant_set_mask[i] = 1.0;
-            }
-        }
-
-        delassus.try_inverse().unwrap()
-    }
-
     pub fn from_params(
         params: &IntegrationParameters,
         joint_id: JointIndex,
@@ -204,7 +205,8 @@ impl GenericVelocityConstraint {
     ) -> Self {
         let anchor1 = rb1.position * joint.local_anchor1;
         let anchor2 = rb2.position * joint.local_anchor2;
-        let basis = anchor1.rotation;
+        let basis1 = anchor1.rotation;
+        let basis2 = anchor2.rotation;
         let im1 = rb1.effective_inv_mass;
         let im2 = rb2.effective_inv_mass;
         let ii1 = rb1.effective_world_inv_inertia_sqrt.squared();
@@ -219,7 +221,7 @@ impl GenericVelocityConstraint {
         let mut max_velocity = joint.max_velocity;
         let mut dependant_set_mask = SpacialVector::repeat(1.0);
 
-        let pos_rhs = Self::compute_position_error(joint, &anchor1, &anchor2, &basis)
+        let pos_rhs = Self::compute_position_error(joint, &anchor1, &anchor2, &basis1)
             * params.inv_dt()
             * params.joint_erp;
 
@@ -236,19 +238,28 @@ impl GenericVelocityConstraint {
             }
         }
 
-        let rhs =
+        let rhs = Self::compute_velocity_error(
-            Self::compute_velocity_error(&min_velocity, &max_velocity, &r1, &r2, &basis, rb1, rb2);
+            &min_velocity,
+            &max_velocity,
+            &r1,
+            &r2,
+            &basis1,
+            &basis2,
+            rb1,
+            rb2,
+        );
         let rhs_lin = rhs.xyz();
         let rhs_ang = rhs.fixed_rows::<Dim>(DIM).into();
 
         // TODO: we should keep the SdpMatrix3 type.
-        let rotmat = basis.to_rotation_matrix().into_inner();
+        let rotmat1 = basis1.to_rotation_matrix().into_inner();
-        let rmat1 = r1.gcross_matrix() * rotmat;
+        let rotmat2 = basis2.to_rotation_matrix().into_inner();
-        let rmat2 = r2.gcross_matrix() * rotmat;
+        let rmat1 = r1.gcross_matrix() * rotmat1;
+        let rmat2 = r2.gcross_matrix() * rotmat2;
         let delassus00 = (ii1.quadform(&rmat1).add_diagonal(im1)
             + ii2.quadform(&rmat2).add_diagonal(im2))
         .into_matrix();
-        let delassus11 = (ii1.quadform(&rotmat) + ii2.quadform(&rotmat)).into_matrix();
+        let delassus11 = (ii1.quadform(&rotmat1) + ii2.quadform(&rotmat2)).into_matrix();
 
         let inv_lhs_lin = GenericVelocityConstraint::invert_partial_delassus_matrix(
             &min_pos_impulse.xyz(),
@@ -288,7 +299,8 @@ impl GenericVelocityConstraint {
             inv_lhs_ang,
             r1,
             r2,
-            basis,
+            basis1,
+            basis2,
             dependant_set_mask,
             vel: GenericConstraintPart {
                 lin_impulse,
@@ -307,21 +319,20 @@ impl GenericVelocityConstraint {
         let mut mj_lambda1 = mj_lambdas[self.mj_lambda1 as usize];
         let mut mj_lambda2 = mj_lambdas[self.mj_lambda2 as usize];
 
-        let lin_impulse = self.basis * self.vel.lin_impulse;
+        let lin_impulse1 = self.basis1 * self.vel.lin_impulse;
-        #[cfg(feature = "dim2")]
+        let ang_impulse1 = self.basis1 * self.vel.ang_impulse;
-        let ang_impulse = self.basis * self.vel.impulse[2];
+        let lin_impulse2 = self.basis2 * self.vel.lin_impulse;
-        #[cfg(feature = "dim3")]
+        let ang_impulse2 = self.basis2 * self.vel.ang_impulse;
-        let ang_impulse = self.basis * self.vel.ang_impulse;
 
-        mj_lambda1.linear += self.im1 * lin_impulse;
+        mj_lambda1.linear += self.im1 * lin_impulse1;
         mj_lambda1.angular += self
             .ii1_sqrt
-            .transform_vector(ang_impulse + self.r1.gcross(lin_impulse));
+            .transform_vector(ang_impulse1 + self.r1.gcross(lin_impulse1));
 
-        mj_lambda2.linear -= self.im2 * lin_impulse;
+        mj_lambda2.linear -= self.im2 * lin_impulse2;
         mj_lambda2.angular -= self
             .ii2_sqrt
-            .transform_vector(ang_impulse + self.r2.gcross(lin_impulse));
+            .transform_vector(ang_impulse2 + self.r2.gcross(lin_impulse2));
 
         mj_lambdas[self.mj_lambda1 as usize] = mj_lambda1;
         mj_lambdas[self.mj_lambda2 as usize] = mj_lambda2;
@@ -441,6 +452,7 @@ impl GenericVelocityGroundConstraint {
             &r1,
             &r2,
             &basis,
+            &basis,
             rb1,
             rb2,
         );
@@ -585,28 +597,30 @@ impl GenericConstraintPart {
             let ang_vel1 = parent.ii1_sqrt.transform_vector(mj_lambda1.angular);
             let ang_vel2 = parent.ii2_sqrt.transform_vector(mj_lambda2.angular);
 
-            let dvel = parent.basis.inverse_transform_vector(
+            let dvel = parent
-                &(-mj_lambda1.linear - ang_vel1.gcross(parent.r1)
+                .basis1
-                    + mj_lambda2.linear
+                .inverse_transform_vector(&(-mj_lambda1.linear - ang_vel1.gcross(parent.r1)))
-                    + ang_vel2.gcross(parent.r2)),
+                + parent
-            );
+                    .basis2
+                    .inverse_transform_vector(&(mj_lambda2.linear + ang_vel2.gcross(parent.r2)));
 
             let err = dvel + self.rhs_lin;
 
             new_lin_impulse = (self.lin_impulse + parent.inv_lhs_lin * err)
                 .sup(&self.min_lin_impulse)
                 .inf(&self.max_lin_impulse);
-            let effective_impulse = parent.basis * (new_lin_impulse - self.lin_impulse);
+            let effective_impulse1 = parent.basis1 * (new_lin_impulse - self.lin_impulse);
+            let effective_impulse2 = parent.basis2 * (new_lin_impulse - self.lin_impulse);
 
-            mj_lambda1.linear += parent.im1 * effective_impulse;
+            mj_lambda1.linear += parent.im1 * effective_impulse1;
             mj_lambda1.angular += parent
                 .ii1_sqrt
-                .transform_vector(parent.r1.gcross(effective_impulse));
+                .transform_vector(parent.r1.gcross(effective_impulse1));
 
-            mj_lambda2.linear -= parent.im2 * effective_impulse;
+            mj_lambda2.linear -= parent.im2 * effective_impulse2;
             mj_lambda2.angular -= parent
                 .ii2_sqrt
-                .transform_vector(parent.r2.gcross(effective_impulse));
+                .transform_vector(parent.r2.gcross(effective_impulse2));
         }
 
         /*
@@ -618,18 +632,18 @@ impl GenericConstraintPart {
             let ang_vel1 = parent.ii1_sqrt.transform_vector(mj_lambda1.angular);
             let ang_vel2 = parent.ii2_sqrt.transform_vector(mj_lambda2.angular);
 
-            let dvel = parent
+            let dvel = parent.basis2.inverse_transform_vector(&ang_vel2)
-                .basis
+                - parent.basis1.inverse_transform_vector(&ang_vel1);
-                .inverse_transform_vector(&(ang_vel2 - ang_vel1));
             let err = dvel + self.rhs_ang;
 
             new_ang_impulse = (self.ang_impulse + parent.inv_lhs_ang * err)
                 .sup(&self.min_ang_impulse)
                 .inf(&self.max_ang_impulse);
-            let effective_impulse = parent.basis * (new_ang_impulse - self.ang_impulse);
+            let effective_impulse1 = parent.basis1 * (new_ang_impulse - self.ang_impulse);
+            let effective_impulse2 = parent.basis2 * (new_ang_impulse - self.ang_impulse);
 
-            mj_lambda1.angular += parent.ii1_sqrt.transform_vector(effective_impulse);
+            mj_lambda1.angular += parent.ii1_sqrt.transform_vector(effective_impulse1);
-            mj_lambda2.angular -= parent.ii2_sqrt.transform_vector(effective_impulse);
+            mj_lambda2.angular -= parent.ii2_sqrt.transform_vector(effective_impulse2);
         }
 
         (new_lin_impulse, new_ang_impulse)

src/dynamics/solver/joint_constraint/joint_constraint.rs

@@ -14,9 +14,9 @@ use super::{
 #[cfg(feature = "dim3")]
 #[cfg(feature = "simd-is-enabled")]
 use super::{WRevoluteVelocityConstraint, WRevoluteVelocityGroundConstraint};
-use crate::dynamics::solver::joint_constraint::generic_velocity_constraint::{
+// use crate::dynamics::solver::joint_constraint::generic_velocity_constraint::{
-    GenericVelocityConstraint, GenericVelocityGroundConstraint,
+//     GenericVelocityConstraint, GenericVelocityGroundConstraint,
-};
+// };
 use crate::dynamics::solver::DeltaVel;
 use crate::dynamics::{
     IntegrationParameters, Joint, JointGraphEdge, JointIndex, JointParams, RigidBodySet,
@@ -38,12 +38,12 @@ pub(crate) enum AnyJointVelocityConstraint {
     WFixedConstraint(WFixedVelocityConstraint),
     #[cfg(feature = "simd-is-enabled")]
     WFixedGroundConstraint(WFixedVelocityGroundConstraint),
-    GenericConstraint(GenericVelocityConstraint),
+    // GenericConstraint(GenericVelocityConstraint),
-    GenericGroundConstraint(GenericVelocityGroundConstraint),
+    // GenericGroundConstraint(GenericVelocityGroundConstraint),
-    #[cfg(feature = "simd-is-enabled")]
+    // #[cfg(feature = "simd-is-enabled")]
-    WGenericConstraint(WGenericVelocityConstraint),
+    // WGenericConstraint(WGenericVelocityConstraint),
-    #[cfg(feature = "simd-is-enabled")]
+    // #[cfg(feature = "simd-is-enabled")]
-    WGenericGroundConstraint(WGenericVelocityGroundConstraint),
+    // WGenericGroundConstraint(WGenericVelocityGroundConstraint),
     PrismaticConstraint(PrismaticVelocityConstraint),
     PrismaticGroundConstraint(PrismaticVelocityGroundConstraint),
     #[cfg(feature = "simd-is-enabled")]
@@ -89,9 +89,9 @@ impl AnyJointVelocityConstraint {
             JointParams::PrismaticJoint(p) => AnyJointVelocityConstraint::PrismaticConstraint(
                 PrismaticVelocityConstraint::from_params(params, joint_id, rb1, rb2, p),
             ),
-            JointParams::GenericJoint(p) => AnyJointVelocityConstraint::GenericConstraint(
+            // JointParams::GenericJoint(p) => AnyJointVelocityConstraint::GenericConstraint(
-                GenericVelocityConstraint::from_params(params, joint_id, rb1, rb2, p),
+            //     GenericVelocityConstraint::from_params(params, joint_id, rb1, rb2, p),
-            ),
+            // ),
             #[cfg(feature = "dim3")]
             JointParams::RevoluteJoint(p) => AnyJointVelocityConstraint::RevoluteConstraint(
                 RevoluteVelocityConstraint::from_params(params, joint_id, rb1, rb2, p),
@@ -167,11 +167,11 @@ impl AnyJointVelocityConstraint {
             JointParams::FixedJoint(p) => AnyJointVelocityConstraint::FixedGroundConstraint(
                 FixedVelocityGroundConstraint::from_params(params, joint_id, rb1, rb2, p, flipped),
             ),
-            JointParams::GenericJoint(p) => AnyJointVelocityConstraint::GenericGroundConstraint(
+            // JointParams::GenericJoint(p) => AnyJointVelocityConstraint::GenericGroundConstraint(
-                GenericVelocityGroundConstraint::from_params(
+            //     GenericVelocityGroundConstraint::from_params(
-                    params, joint_id, rb1, rb2, p, flipped,
+            //         params, joint_id, rb1, rb2, p, flipped,
-                ),
+            //     ),
-            ),
+            // ),
             JointParams::PrismaticJoint(p) => {
                 AnyJointVelocityConstraint::PrismaticGroundConstraint(
                     PrismaticVelocityGroundConstraint::from_params(
@@ -180,10 +180,8 @@ impl AnyJointVelocityConstraint {
                 )
             }
             #[cfg(feature = "dim3")]
-            JointParams::RevoluteJoint(p) => AnyJointVelocityConstraint::RevoluteGroundConstraint(
+            JointParams::RevoluteJoint(p) => RevoluteVelocityGroundConstraint::from_params(
-                RevoluteVelocityGroundConstraint::from_params(
+                params, joint_id, rb1, rb2, p, flipped,
-                    params, joint_id, rb1, rb2, p, flipped,
-                ),
             ),
         }
     }
@@ -267,12 +265,12 @@ impl AnyJointVelocityConstraint {
             AnyJointVelocityConstraint::WFixedConstraint(c) => c.warmstart(mj_lambdas),
             #[cfg(feature = "simd-is-enabled")]
             AnyJointVelocityConstraint::WFixedGroundConstraint(c) => c.warmstart(mj_lambdas),
-            AnyJointVelocityConstraint::GenericConstraint(c) => c.warmstart(mj_lambdas),
+            // AnyJointVelocityConstraint::GenericConstraint(c) => c.warmstart(mj_lambdas),
-            AnyJointVelocityConstraint::GenericGroundConstraint(c) => c.warmstart(mj_lambdas),
+            // AnyJointVelocityConstraint::GenericGroundConstraint(c) => c.warmstart(mj_lambdas),
-            #[cfg(feature = "simd-is-enabled")]
+            // #[cfg(feature = "simd-is-enabled")]
-            AnyJointVelocityConstraint::WGenericConstraint(c) => c.warmstart(mj_lambdas),
+            // AnyJointVelocityConstraint::WGenericConstraint(c) => c.warmstart(mj_lambdas),
-            #[cfg(feature = "simd-is-enabled")]
+            // #[cfg(feature = "simd-is-enabled")]
-            AnyJointVelocityConstraint::WGenericGroundConstraint(c) => c.warmstart(mj_lambdas),
+            // AnyJointVelocityConstraint::WGenericGroundConstraint(c) => c.warmstart(mj_lambdas),
             AnyJointVelocityConstraint::PrismaticConstraint(c) => c.warmstart(mj_lambdas),
             AnyJointVelocityConstraint::PrismaticGroundConstraint(c) => c.warmstart(mj_lambdas),
             #[cfg(feature = "simd-is-enabled")]
@@ -307,12 +305,12 @@ impl AnyJointVelocityConstraint {
             AnyJointVelocityConstraint::WFixedConstraint(c) => c.solve(mj_lambdas),
             #[cfg(feature = "simd-is-enabled")]
             AnyJointVelocityConstraint::WFixedGroundConstraint(c) => c.solve(mj_lambdas),
-            AnyJointVelocityConstraint::GenericConstraint(c) => c.solve(mj_lambdas),
+            // AnyJointVelocityConstraint::GenericConstraint(c) => c.solve(mj_lambdas),
-            AnyJointVelocityConstraint::GenericGroundConstraint(c) => c.solve(mj_lambdas),
+            // AnyJointVelocityConstraint::GenericGroundConstraint(c) => c.solve(mj_lambdas),
-            #[cfg(feature = "simd-is-enabled")]
+            // #[cfg(feature = "simd-is-enabled")]
-            AnyJointVelocityConstraint::WGenericConstraint(c) => c.solve(mj_lambdas),
+            // AnyJointVelocityConstraint::WGenericConstraint(c) => c.solve(mj_lambdas),
-            #[cfg(feature = "simd-is-enabled")]
+            // #[cfg(feature = "simd-is-enabled")]
-            AnyJointVelocityConstraint::WGenericGroundConstraint(c) => c.solve(mj_lambdas),
+            // AnyJointVelocityConstraint::WGenericGroundConstraint(c) => c.solve(mj_lambdas),
             AnyJointVelocityConstraint::PrismaticConstraint(c) => c.solve(mj_lambdas),
             AnyJointVelocityConstraint::PrismaticGroundConstraint(c) => c.solve(mj_lambdas),
             #[cfg(feature = "simd-is-enabled")]
@@ -355,16 +353,16 @@ impl AnyJointVelocityConstraint {
             AnyJointVelocityConstraint::WFixedGroundConstraint(c) => {
                 c.writeback_impulses(joints_all)
             }
-            AnyJointVelocityConstraint::GenericConstraint(c) => c.writeback_impulses(joints_all),
+            // AnyJointVelocityConstraint::GenericConstraint(c) => c.writeback_impulses(joints_all),
-            AnyJointVelocityConstraint::GenericGroundConstraint(c) => {
+            // AnyJointVelocityConstraint::GenericGroundConstraint(c) => {
-                c.writeback_impulses(joints_all)
+            //     c.writeback_impulses(joints_all)
-            }
+            // }
-            #[cfg(feature = "simd-is-enabled")]
+            // #[cfg(feature = "simd-is-enabled")]
-            AnyJointVelocityConstraint::WGenericConstraint(c) => c.writeback_impulses(joints_all),
+            // AnyJointVelocityConstraint::WGenericConstraint(c) => c.writeback_impulses(joints_all),
-            #[cfg(feature = "simd-is-enabled")]
+            // #[cfg(feature = "simd-is-enabled")]
-            AnyJointVelocityConstraint::WGenericGroundConstraint(c) => {
+            // AnyJointVelocityConstraint::WGenericGroundConstraint(c) => {
-                c.writeback_impulses(joints_all)
+            //     c.writeback_impulses(joints_all)
-            }
+            // }
             AnyJointVelocityConstraint::PrismaticConstraint(c) => c.writeback_impulses(joints_all),
             AnyJointVelocityConstraint::PrismaticGroundConstraint(c) => {
                 c.writeback_impulses(joints_all)

src/dynamics/solver/joint_constraint/joint_position_constraint.rs

@@ -1,7 +1,6 @@
 use super::{
     BallPositionConstraint, BallPositionGroundConstraint, FixedPositionConstraint,
-    FixedPositionGroundConstraint, GenericPositionConstraint, GenericPositionGroundConstraint,
+    FixedPositionGroundConstraint, PrismaticPositionConstraint, PrismaticPositionGroundConstraint,
-    PrismaticPositionConstraint, PrismaticPositionGroundConstraint,
 };
 #[cfg(feature = "dim3")]
 use super::{RevolutePositionConstraint, RevolutePositionGroundConstraint};
@@ -33,12 +32,12 @@ pub(crate) enum AnyJointPositionConstraint {
     WFixedJoint(WFixedPositionConstraint),
     #[cfg(feature = "simd-is-enabled")]
     WFixedGroundConstraint(WFixedPositionGroundConstraint),
-    GenericJoint(GenericPositionConstraint),
+    // GenericJoint(GenericPositionConstraint),
-    GenericGroundConstraint(GenericPositionGroundConstraint),
+    // GenericGroundConstraint(GenericPositionGroundConstraint),
-    #[cfg(feature = "simd-is-enabled")]
+    // #[cfg(feature = "simd-is-enabled")]
-    WGenericJoint(WGenericPositionConstraint),
+    // WGenericJoint(WGenericPositionConstraint),
-    #[cfg(feature = "simd-is-enabled")]
+    // #[cfg(feature = "simd-is-enabled")]
-    WGenericGroundConstraint(WGenericPositionGroundConstraint),
+    // WGenericGroundConstraint(WGenericPositionGroundConstraint),
     PrismaticJoint(PrismaticPositionConstraint),
     PrismaticGroundConstraint(PrismaticPositionGroundConstraint),
     #[cfg(feature = "simd-is-enabled")]
@@ -69,9 +68,9 @@ impl AnyJointPositionConstraint {
             JointParams::FixedJoint(p) => AnyJointPositionConstraint::FixedJoint(
                 FixedPositionConstraint::from_params(rb1, rb2, p),
             ),
-            JointParams::GenericJoint(p) => AnyJointPositionConstraint::GenericJoint(
+            // JointParams::GenericJoint(p) => AnyJointPositionConstraint::GenericJoint(
-                GenericPositionConstraint::from_params(rb1, rb2, p),
+            //     GenericPositionConstraint::from_params(rb1, rb2, p),
-            ),
+            // ),
             JointParams::PrismaticJoint(p) => AnyJointPositionConstraint::PrismaticJoint(
                 PrismaticPositionConstraint::from_params(rb1, rb2, p),
             ),
@@ -140,9 +139,9 @@ impl AnyJointPositionConstraint {
             JointParams::FixedJoint(p) => AnyJointPositionConstraint::FixedGroundConstraint(
                 FixedPositionGroundConstraint::from_params(rb1, rb2, p, flipped),
             ),
-            JointParams::GenericJoint(p) => AnyJointPositionConstraint::GenericGroundConstraint(
+            // JointParams::GenericJoint(p) => AnyJointPositionConstraint::GenericGroundConstraint(
-                GenericPositionGroundConstraint::from_params(rb1, rb2, p, flipped),
+            //     GenericPositionGroundConstraint::from_params(rb1, rb2, p, flipped),
-            ),
+            // ),
             JointParams::PrismaticJoint(p) => {
                 AnyJointPositionConstraint::PrismaticGroundConstraint(
                     PrismaticPositionGroundConstraint::from_params(rb1, rb2, p, flipped),
@@ -219,12 +218,12 @@ impl AnyJointPositionConstraint {
             AnyJointPositionConstraint::WFixedJoint(c) => c.solve(params, positions),
             #[cfg(feature = "simd-is-enabled")]
             AnyJointPositionConstraint::WFixedGroundConstraint(c) => c.solve(params, positions),
-            AnyJointPositionConstraint::GenericJoint(c) => c.solve(params, positions),
+            // AnyJointPositionConstraint::GenericJoint(c) => c.solve(params, positions),
-            AnyJointPositionConstraint::GenericGroundConstraint(c) => c.solve(params, positions),
+            // AnyJointPositionConstraint::GenericGroundConstraint(c) => c.solve(params, positions),
-            #[cfg(feature = "simd-is-enabled")]
+            // #[cfg(feature = "simd-is-enabled")]
-            AnyJointPositionConstraint::WGenericJoint(c) => c.solve(params, positions),
+            // AnyJointPositionConstraint::WGenericJoint(c) => c.solve(params, positions),
-            #[cfg(feature = "simd-is-enabled")]
+            // #[cfg(feature = "simd-is-enabled")]
-            AnyJointPositionConstraint::WGenericGroundConstraint(c) => c.solve(params, positions),
+            // AnyJointPositionConstraint::WGenericGroundConstraint(c) => c.solve(params, positions),
             AnyJointPositionConstraint::PrismaticJoint(c) => c.solve(params, positions),
             AnyJointPositionConstraint::PrismaticGroundConstraint(c) => c.solve(params, positions),
             #[cfg(feature = "simd-is-enabled")]

src/dynamics/solver/joint_constraint/mod.rs

@@ -18,20 +18,20 @@ pub(self) use fixed_velocity_constraint::{FixedVelocityConstraint, FixedVelocity
 pub(self) use fixed_velocity_constraint_wide::{
     WFixedVelocityConstraint, WFixedVelocityGroundConstraint,
 };
-pub(self) use generic_position_constraint::{
+// pub(self) use generic_position_constraint::{
-    GenericPositionConstraint, GenericPositionGroundConstraint,
+//     GenericPositionConstraint, GenericPositionGroundConstraint,
-};
+// };
-#[cfg(feature = "simd-is-enabled")]
+// #[cfg(feature = "simd-is-enabled")]
-pub(self) use generic_position_constraint_wide::{
+// pub(self) use generic_position_constraint_wide::{
-    WGenericPositionConstraint, WGenericPositionGroundConstraint,
+//     WGenericPositionConstraint, WGenericPositionGroundConstraint,
-};
+// };
-pub(self) use generic_velocity_constraint::{
+// pub(self) use generic_velocity_constraint::{
-    GenericVelocityConstraint, GenericVelocityGroundConstraint,
+//     GenericVelocityConstraint, GenericVelocityGroundConstraint,
-};
+// };
-#[cfg(feature = "simd-is-enabled")]
+// #[cfg(feature = "simd-is-enabled")]
-pub(self) use generic_velocity_constraint_wide::{
+// pub(self) use generic_velocity_constraint_wide::{
-    WGenericVelocityConstraint, WGenericVelocityGroundConstraint,
+//     WGenericVelocityConstraint, WGenericVelocityGroundConstraint,
-};
+// };
 
 pub(crate) use joint_constraint::AnyJointVelocityConstraint;
 pub(crate) use joint_position_constraint::AnyJointPositionConstraint;
@@ -78,12 +78,12 @@ mod fixed_position_constraint_wide;
 mod fixed_velocity_constraint;
 #[cfg(feature = "simd-is-enabled")]
 mod fixed_velocity_constraint_wide;
-mod generic_position_constraint;
+// mod generic_position_constraint;
-#[cfg(feature = "simd-is-enabled")]
+// #[cfg(feature = "simd-is-enabled")]
-mod generic_position_constraint_wide;
+// mod generic_position_constraint_wide;
-mod generic_velocity_constraint;
+// mod generic_velocity_constraint;
-#[cfg(feature = "simd-is-enabled")]
+// #[cfg(feature = "simd-is-enabled")]
-mod generic_velocity_constraint_wide;
+// mod generic_velocity_constraint_wide;
 mod joint_constraint;
 mod joint_position_constraint;
 mod prismatic_position_constraint;

src/dynamics/solver/joint_constraint/revolute_position_constraint.rs

@@ -59,72 +59,6 @@ impl RevolutePositionConstraint {
         let mut position1 = positions[self.position1 as usize];
         let mut position2 = positions[self.position2 as usize];
 
-        let anchor1 = position1 * self.local_anchor1;
-        let anchor2 = position2 * self.local_anchor2;
-        let axis1 = position1 * self.local_axis1;
-        let axis2 = position2 * self.local_axis2;
-
-        let basis1 = Matrix3x2::from_columns(&[
-            position1 * self.local_basis1[0],
-            position1 * self.local_basis1[1],
-        ]);
-        let basis2 = Matrix3x2::from_columns(&[
-            position2 * self.local_basis2[0],
-            position2 * self.local_basis2[1],
-        ]);
-
-        let basis_filter1 = basis1 * basis1.transpose();
-        let basis_filter2 = basis2 * basis2.transpose();
-        let basis2 = basis_filter2 * basis1;
-
-        let r1 = anchor1 - position1 * self.local_com1;
-        let r2 = anchor2 - position2 * self.local_com2;
-        let r1_mat = basis_filter1 * r1.gcross_matrix();
-        let r2_mat = basis_filter2 * r2.gcross_matrix();
-
-        let mut lhs = Matrix5::zeros();
-        let lhs00 = self.ii2.quadform(&r2_mat).add_diagonal(self.im2)
-            + self.ii1.quadform(&r1_mat).add_diagonal(self.im1);
-        let lhs10 = basis2.tr_mul(&(self.ii2 * r2_mat)) + basis1.tr_mul(&(self.ii1 * r1_mat));
-        let lhs11 = (self.ii1.quadform3x2(&basis1) + self.ii2.quadform3x2(&basis2)).into_matrix();
-
-        // Note that cholesky won't read the upper-right part
-        // of lhs so we don't have to fill it.
-        lhs.fixed_slice_mut::<na::U3, na::U3>(0, 0)
-            .copy_from(&lhs00.into_matrix());
-        lhs.fixed_slice_mut::<na::U2, na::U3>(3, 0)
-            .copy_from(&lhs10);
-        lhs.fixed_slice_mut::<na::U2, na::U2>(3, 3)
-            .copy_from(&lhs11);
-
-        let inv_lhs = na::Cholesky::new_unchecked(lhs).inverse();
-
-        let delta_tra = anchor2 - anchor1;
-        let lin_error = delta_tra * params.joint_erp;
-        let delta_rot =
-            Rotation::rotation_between_axis(&axis1, &axis2).unwrap_or_else(Rotation::identity);
-
-        let ang_error = basis1.tr_mul(&delta_rot.scaled_axis()) * params.joint_erp;
-        let error = na::Vector5::new(
-            lin_error.x,
-            lin_error.y,
-            lin_error.z,
-            ang_error.x,
-            ang_error.y,
-        );
-        let impulse = inv_lhs * error;
-        let lin_impulse = impulse.fixed_rows::<na::U3>(0).into_owned();
-        let ang_impulse1 = basis1 * impulse.fixed_rows::<na::U2>(3).into_owned();
-        let ang_impulse2 = basis2 * impulse.fixed_rows::<na::U2>(3).into_owned();
-
-        let rot1 = self.ii1 * (r1_mat * lin_impulse + ang_impulse1);
-        let rot2 = self.ii2 * (r2_mat * lin_impulse + ang_impulse2);
-        position1.rotation = Rotation::new(rot1) * position1.rotation;
-        position2.rotation = Rotation::new(-rot2) * position2.rotation;
-        position1.translation.vector += self.im1 * lin_impulse;
-        position2.translation.vector -= self.im2 * lin_impulse;
-
-        /*
         /*
          * Linear part.
          */
@@ -134,7 +68,8 @@ impl RevolutePositionConstraint {
 
             let r1 = anchor1 - position1 * self.local_com1;
             let r2 = anchor2 - position2 * self.local_com2;
-            // TODO: don't the the "to_matrix".
+
+            // TODO: don't do the "to_matrix".
             let lhs = (self
                 .ii2
                 .quadform(&r2.gcross_matrix())
@@ -174,7 +109,6 @@ impl RevolutePositionConstraint {
             position2.rotation =
                 Rotation::new(self.ii2.transform_vector(-ang_impulse)) * position2.rotation;
         }
-         */
 
         positions[self.position1 as usize] = position1;
         positions[self.position2 as usize] = position2;
@@ -249,61 +183,6 @@ impl RevolutePositionGroundConstraint {
     pub fn solve(&self, params: &IntegrationParameters, positions: &mut [Isometry<Real>]) {
         let mut position2 = positions[self.position2 as usize];
 
-        let anchor1 = self.anchor1;
-        let anchor2 = position2 * self.local_anchor2;
-        let axis1 = self.axis1;
-        let axis2 = position2 * self.local_axis2;
-
-        let basis1 = Matrix3x2::from_columns(&self.basis1[..]);
-        let basis2 = Matrix3x2::from_columns(&[
-            position2 * self.local_basis2[0],
-            position2 * self.local_basis2[1],
-        ]);
-
-        let basis_filter2 = basis2 * basis2.transpose();
-        let basis2 = basis_filter2 * basis1;
-
-        let r2 = anchor2 - position2 * self.local_com2;
-        let r2_mat = basis_filter2 * r2.gcross_matrix();
-
-        let mut lhs = Matrix5::zeros();
-        let lhs00 = self.ii2.quadform(&r2_mat).add_diagonal(self.im2);
-        let lhs10 = basis2.tr_mul(&(self.ii2 * r2_mat));
-        let lhs11 = self.ii2.quadform3x2(&basis2).into_matrix();
-
-        // Note that cholesky won't read the upper-right part
-        // of lhs so we don't have to fill it.
-        lhs.fixed_slice_mut::<na::U3, na::U3>(0, 0)
-            .copy_from(&lhs00.into_matrix());
-        lhs.fixed_slice_mut::<na::U2, na::U3>(3, 0)
-            .copy_from(&lhs10);
-        lhs.fixed_slice_mut::<na::U2, na::U2>(3, 3)
-            .copy_from(&lhs11);
-
-        let inv_lhs = na::Cholesky::new_unchecked(lhs).inverse();
-
-        let delta_tra = anchor2 - anchor1;
-        let lin_error = delta_tra * params.joint_erp;
-        let delta_rot =
-            Rotation::rotation_between_axis(&axis1, &axis2).unwrap_or_else(Rotation::identity);
-
-        let ang_error = basis1.tr_mul(&delta_rot.scaled_axis()) * params.joint_erp;
-        let error = na::Vector5::new(
-            lin_error.x,
-            lin_error.y,
-            lin_error.z,
-            ang_error.x,
-            ang_error.y,
-        );
-        let impulse = inv_lhs * error;
-        let lin_impulse = impulse.fixed_rows::<na::U3>(0).into_owned();
-        let ang_impulse2 = basis2 * impulse.fixed_rows::<na::U2>(3).into_owned();
-
-        let rot2 = self.ii2 * (r2_mat * lin_impulse + ang_impulse2);
-        position2.rotation = Rotation::new(-rot2) * position2.rotation;
-        position2.translation.vector -= self.im2 * lin_impulse;
-
-        /*
         /*
          * Linear part.
          */
@@ -338,7 +217,6 @@ impl RevolutePositionGroundConstraint {
             let ang_error = delta_rot.scaled_axis() * params.joint_erp;
             position2.rotation = Rotation::new(-ang_error) * position2.rotation;
         }
-        */
 
         positions[self.position2 as usize] = position2;
     }

src/dynamics/solver/joint_constraint/revolute_velocity_constraint.rs

@@ -1,11 +1,11 @@
 use crate::dynamics::solver::{AnyJointVelocityConstraint, AnyVelocityConstraint, DeltaVel};
 use crate::dynamics::{
-    GenericJoint, IntegrationParameters, JointGraphEdge, JointIndex, JointParams, RevoluteJoint,
+    IntegrationParameters, JointGraphEdge, JointIndex, JointParams, RevoluteJoint, RigidBody,
-    RigidBody,
 };
 use crate::math::{AngularInertia, Real, Rotation, Vector};
 use crate::na::UnitQuaternion;
 use crate::utils::{WAngularInertia, WCross, WCrossMatrix};
+use downcast_rs::Downcast;
 use na::{Cholesky, Matrix3, Matrix3x2, Matrix5, RealField, Vector5, U2, U3};
 
 #[derive(Debug)]
@@ -26,6 +26,7 @@ pub(crate) struct RevoluteVelocityConstraint {
     motor_rhs: Real,
     motor_impulse: Real,
     motor_max_impulse: Real,
+    motor_angle: Real, // Exists only to write it back into the joint.
 
     motor_axis1: Vector<Real>,
     motor_axis2: Vector<Real>,
@@ -47,7 +48,7 @@ impl RevoluteVelocityConstraint {
         rb1: &RigidBody,
         rb2: &RigidBody,
         joint: &RevoluteJoint,
-    ) -> AnyJointVelocityConstraint {
+    ) -> Self {
         // Linear part.
         let anchor1 = rb1.position * joint.local_anchor1;
         let anchor2 = rb2.position * joint.local_anchor2;
@@ -100,16 +101,35 @@ impl RevoluteVelocityConstraint {
         let motor_axis2 = rb2.position * *joint.local_axis2;
         let mut motor_rhs = 0.0;
         let mut motor_inv_lhs = 0.0;
-        let mut motor_max_impulse = 0.0;
+        let mut motor_max_impulse = joint.motor_max_impulse;
+        let mut motor_angle = 0.0;
 
-        if let Some(motor_target_vel) = joint.motor_target_vel {
+        let (stiffness, damping, gamma, keep_lhs) = joint.motor_model.combine_coefficients(
-            motor_rhs =
+            params.dt,
-                rb2.angvel.dot(&motor_axis1) - rb1.angvel.dot(&motor_axis1) - motor_target_vel;
+            joint.motor_stiffness,
-            motor_inv_lhs = crate::utils::inv(
+            joint.motor_damping,
-                motor_axis2.dot(&ii2.transform_vector(motor_axis2))
+        );
-                    + motor_axis1.dot(&ii1.transform_vector(motor_axis1)),
+
-            );
+        if stiffness != 0.0 {
-            motor_max_impulse = joint.motor_max_torque;
+            motor_angle = joint.estimate_motor_angle(&rb1.position, &rb2.position);
+            motor_rhs += (motor_angle - joint.motor_target_pos) * stiffness;
+        }
+
+        if damping != 0.0 {
+            let curr_vel = rb2.angvel.dot(&motor_axis2) - rb1.angvel.dot(&motor_axis1);
+            motor_rhs += (curr_vel - joint.motor_target_vel) * damping;
+        }
+
+        if stiffness != 0.0 || damping != 0.0 {
+            motor_inv_lhs = if keep_lhs {
+                crate::utils::inv(
+                    motor_axis2.dot(&ii2.transform_vector(motor_axis2))
+                        + motor_axis1.dot(&ii1.transform_vector(motor_axis1)),
+                ) * gamma
+            } else {
+                gamma
+            };
+            motor_rhs /= gamma;
         }
 
         /*
@@ -125,8 +145,10 @@ impl RevoluteVelocityConstraint {
         let rotated_impulse = basis1.tr_mul(&(axis_rot * joint.world_ang_impulse));
         impulse[3] = rotated_impulse.x * params.warmstart_coeff;
         impulse[4] = rotated_impulse.y * params.warmstart_coeff;
+        let motor_impulse = na::clamp(joint.motor_impulse, -motor_max_impulse, motor_max_impulse)
+            * params.warmstart_coeff;
 
-        let result = RevoluteVelocityConstraint {
+        RevoluteVelocityConstraint {
             joint_id,
             mj_lambda1: rb1.active_set_offset,
             mj_lambda2: rb2.active_set_offset,
@@ -146,10 +168,9 @@ impl RevoluteVelocityConstraint {
             motor_max_impulse,
             motor_axis1,
             motor_axis2,
-            motor_impulse: joint.motor_impulse * params.warmstart_coeff,
+            motor_impulse,
-        };
+            motor_angle,
-
+        }
-        AnyJointVelocityConstraint::RevoluteConstraint(result)
     }
 
     pub fn warmstart(&self, mj_lambdas: &mut [DeltaVel<Real>]) {
@@ -174,7 +195,7 @@ impl RevoluteVelocityConstraint {
         /*
          * Motor
          */
-        {
+        if self.motor_inv_lhs != 0.0 {
             mj_lambda1.angular += self
                 .ii1_sqrt
                 .transform_vector(self.motor_axis1 * self.motor_impulse);
@@ -224,8 +245,14 @@ impl RevoluteVelocityConstraint {
             let ang_vel2 = self.ii2_sqrt.transform_vector(mj_lambda2.angular);
             let ang_dvel = ang_vel2.dot(&self.motor_axis2) - ang_vel1.dot(&self.motor_axis1);
             let rhs = ang_dvel + self.motor_rhs;
-            let impulse = self.motor_inv_lhs * rhs;
+
-            self.motor_impulse += impulse;
+            let new_motor_impulse = na::clamp(
+                self.motor_impulse + self.motor_inv_lhs * rhs,
+                -self.motor_max_impulse,
+                self.motor_max_impulse,
+            );
+            let impulse = new_motor_impulse - self.motor_impulse;
+            self.motor_impulse = new_motor_impulse;
 
             mj_lambda1.angular += self.ii1_sqrt.transform_vector(self.motor_axis1 * impulse);
             mj_lambda2.angular -= self.ii2_sqrt.transform_vector(self.motor_axis2 * impulse);
@@ -242,6 +269,7 @@ impl RevoluteVelocityConstraint {
             let rot_part = self.impulse.fixed_rows::<U2>(3).into_owned();
             revolute.world_ang_impulse = self.basis1 * rot_part;
             revolute.prev_axis1 = self.motor_axis1;
+            revolute.motor_last_angle = self.motor_angle;
             revolute.motor_impulse = self.motor_impulse;
         }
     }
@@ -264,6 +292,7 @@ pub(crate) struct RevoluteVelocityGroundConstraint {
     motor_rhs: Real,
     motor_impulse: Real,
     motor_max_impulse: Real,
+    motor_angle: Real, // Exists just for writing it into the joint.
 
     basis2: Matrix3x2<Real>,
 
@@ -328,18 +357,41 @@ impl RevoluteVelocityGroundConstraint {
         /*
          * Motor part.
          */
+        let motor_axis1 = rb1.position * *joint.local_axis1;
+        let motor_axis2 = rb2.position * *joint.local_axis2;
         let mut motor_rhs = 0.0;
         let mut motor_inv_lhs = 0.0;
-        let mut motor_max_impulse = 0.0;
+        let mut motor_max_impulse = joint.motor_max_impulse;
-        let mut motor_axis2 = Vector::zeros();
+        let mut motor_angle = 0.0;
 
-        if let Some(motor_target_vel) = joint.motor_target_vel {
+        let (stiffness, damping, gamma, keep_lhs) = joint.motor_model.combine_coefficients(
-            motor_axis2 = rb2.position * *joint.local_axis2;
+            params.dt,
-            motor_rhs = rb2.angvel.dot(&motor_axis2) - motor_target_vel;
+            joint.motor_stiffness,
-            motor_inv_lhs = crate::utils::inv(motor_axis2.dot(&ii2.transform_vector(motor_axis2)));
+            joint.motor_damping,
-            motor_max_impulse = joint.motor_max_torque;
+        );
+
+        if stiffness != 0.0 {
+            motor_angle = joint.estimate_motor_angle(&rb1.position, &rb2.position);
+            motor_rhs += (motor_angle - joint.motor_target_pos) * stiffness;
         }
 
+        if damping != 0.0 {
+            let curr_vel = rb2.angvel.dot(&motor_axis2) - rb1.angvel.dot(&motor_axis1);
+            motor_rhs += (curr_vel - joint.motor_target_vel) * damping;
+        }
+
+        if stiffness != 0.0 || damping != 0.0 {
+            motor_inv_lhs = if keep_lhs {
+                crate::utils::inv(motor_axis2.dot(&ii2.transform_vector(motor_axis2))) * gamma
+            } else {
+                gamma
+            };
+            motor_rhs /= gamma;
+        }
+
+        let motor_impulse = na::clamp(joint.motor_impulse, -motor_max_impulse, motor_max_impulse)
+            * params.warmstart_coeff;
+
         let result = RevoluteVelocityGroundConstraint {
             joint_id,
             mj_lambda2: rb2.active_set_offset,
@@ -351,10 +403,11 @@ impl RevoluteVelocityGroundConstraint {
             rhs,
             r2,
             motor_inv_lhs,
-            motor_impulse: joint.motor_impulse,
+            motor_impulse,
             motor_axis2,
             motor_max_impulse,
             motor_rhs,
+            motor_angle,
         };
 
         AnyJointVelocityConstraint::RevoluteGroundConstraint(result)
@@ -374,7 +427,7 @@ impl RevoluteVelocityGroundConstraint {
         /*
          * Motor
          */
-        {
+        if self.motor_inv_lhs != 0.0 {
             mj_lambda2.angular -= self
                 .ii2_sqrt
                 .transform_vector(self.motor_axis2 * self.motor_impulse);
@@ -410,8 +463,14 @@ impl RevoluteVelocityGroundConstraint {
             let ang_vel2 = self.ii2_sqrt.transform_vector(mj_lambda2.angular);
             let ang_dvel = ang_vel2.dot(&self.motor_axis2);
             let rhs = ang_dvel + self.motor_rhs;
-            let impulse = self.motor_inv_lhs * rhs;
+
-            self.motor_impulse += impulse;
+            let new_motor_impulse = na::clamp(
+                self.motor_impulse + self.motor_inv_lhs * rhs,
+                -self.motor_max_impulse,
+                self.motor_max_impulse,
+            );
+            let impulse = new_motor_impulse - self.motor_impulse;
+            self.motor_impulse = new_motor_impulse;
 
             mj_lambda2.angular -= self.ii2_sqrt.transform_vector(self.motor_axis2 * impulse);
         }
@@ -425,6 +484,7 @@ impl RevoluteVelocityGroundConstraint {
         if let JointParams::RevoluteJoint(revolute) = &mut joint.params {
             revolute.impulse = self.impulse;
             revolute.motor_impulse = self.motor_impulse;
+            revolute.motor_last_angle = self.motor_angle;
         }
     }
 }

src_testbed/nphysics_backend.rs

@@ -121,12 +121,11 @@ impl NPhysicsWorld {
                     }
 
                     nphysics_joints.insert(c);
-                }
+                } // JointParams::GenericJoint(_) => {
-                JointParams::GenericJoint(_) => {
+                  //     eprintln!(
-                    eprintln!(
+                  //         "Joint type currently unsupported by the nphysics backend: GenericJoint."
-                        "Joint type currently unsupported by the nphysics backend: GenericJoint."
+                  //     )
-                    )
+                  // }
-                }
             }
         }
 

src_testbed/physx_backend.rs

@@ -344,13 +344,27 @@ impl PhysxWorld {
                             .into_physx()
                             .into();
 
-                        physx_sys::phys_PxRevoluteJointCreate(
+                        let revolute_joint = physx_sys::phys_PxRevoluteJointCreate(
                             physics.as_mut_ptr(),
                             actor1,
                             &frame1 as *const _,
                             actor2,
                             &frame2 as *const _,
                         );
+
+                        physx_sys::PxRevoluteJoint_setDriveVelocity_mut(
+                            revolute_joint,
+                            params.motor_target_vel,
+                            true,
+                        );
+
+                        if params.motor_damping != 0.0 {
+                            physx_sys::PxRevoluteJoint_setRevoluteJointFlag_mut(
+                                revolute_joint,
+                                physx_sys::PxRevoluteJointFlag::eDRIVE_ENABLED,
+                                true,
+                            );
+                        }
                     }
 
                     JointParams::PrismaticJoint(params) => {
@@ -420,12 +434,11 @@ impl PhysxWorld {
                             actor2,
                             &frame2 as *const _,
                         );
-                    }
+                    } // JointParams::GenericJoint(_) => {
-                    JointParams::GenericJoint(_) => {
+                      //     eprintln!(
-                        eprintln!(
+                      //         "Joint type currently unsupported by the PhysX backend: GenericJoint."
-                            "Joint type currently unsupported by the nphysics backend: GenericJoint."
+                      //     )
-                        )
+                      // }
-                    }
                 }
             }
         }