rapier2d 0.7.1

2-dimensional physics engine in Rust.
Documentation 
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use crate::dynamics::{BallJoint, FixedJoint, PrismaticJoint, RevoluteJoint};
use crate::math::{Isometry, Real, SpacialVector};
use crate::na::{Rotation3, UnitQuaternion};

#[derive(Copy, Clone, Debug)]
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
/// A joint that prevents all relative movement between two bodies.
///
/// Given two frames of references, this joint aims to ensure these frame always coincide in world-space.
pub struct GenericJoint {
    /// The frame of reference for the first body affected by this joint, expressed in the local frame
    /// of the first body.
    pub local_anchor1: Isometry<Real>,
    /// The frame of reference for the second body affected by this joint, expressed in the local frame
    /// of the first body.
    pub local_anchor2: Isometry<Real>,
    /// The impulse applied to the first body affected by this joint.
    ///
    /// The impulse applied to the second body affected by this joint is given by `-impulse`.
    /// This combines both linear and angular impulses:
    /// - In 2D, `impulse.xy()` gives the linear impulse, and `impulse.z` the angular impulse.
    /// - In 3D, `impulse.xyz()` gives the linear impulse, and `(impulse[3], impulse[4], impulse[5])` the angular impulse.
    pub impulse: SpacialVector<Real>,

    pub min_position: SpacialVector<Real>,
    pub max_position: SpacialVector<Real>,
    pub min_velocity: SpacialVector<Real>,
    pub max_velocity: SpacialVector<Real>,
    /// The minimum negative impulse the joint can apply on each DoF. Must be <= 0.0
    pub min_impulse: SpacialVector<Real>,
    /// The maximum positive impulse the joint can apply on each DoF. Must be >= 0.0
    pub max_impulse: SpacialVector<Real>,
    /// The minimum negative position impulse the joint can apply on each DoF. Must be <= 0.0
    pub min_pos_impulse: SpacialVector<Real>,
    /// The maximum positive position impulse the joint can apply on each DoF. Must be >= 0.0
    pub max_pos_impulse: SpacialVector<Real>,
}

impl GenericJoint {
    /// Creates a new fixed joint from the frames of reference of both bodies.
    pub fn new(local_anchor1: Isometry<Real>, local_anchor2: Isometry<Real>) -> Self {
        Self {
            local_anchor1,
            local_anchor2,
            impulse: SpacialVector::zeros(),
            min_position: SpacialVector::zeros(),
            max_position: SpacialVector::zeros(),
            min_velocity: SpacialVector::zeros(),
            max_velocity: SpacialVector::zeros(),
            min_impulse: SpacialVector::repeat(-Real::MAX),
            max_impulse: SpacialVector::repeat(Real::MAX),
            min_pos_impulse: SpacialVector::repeat(-Real::MAX),
            max_pos_impulse: SpacialVector::repeat(Real::MAX),
        }
    }

    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;
        self.min_velocity[dof as usize] = -Real::MAX;
        self.max_velocity[dof as usize] = Real::MAX;
        self.min_impulse[dof as usize] = 0.0;
        self.max_impulse[dof as usize] = 0.0;
        self.min_pos_impulse[dof as usize] = 0.0;
        self.max_pos_impulse[dof as usize] = 0.0;
    }

    pub fn set_dof_limits(&mut self, dof: u8, min: Real, max: Real) {
        self.min_position[dof as usize] = min;
        self.max_position[dof as usize] = max;
    }
}

impl From<RevoluteJoint> for GenericJoint {
    fn from(joint: RevoluteJoint) -> Self {
        let basis1 = [*joint.local_axis1, joint.basis1[0], joint.basis1[1]];
        let basis2 = [*joint.local_axis2, joint.basis2[0], joint.basis2[1]];
        let quat1 = UnitQuaternion::from_basis_unchecked(&basis1);
        let quat2 = UnitQuaternion::from_basis_unchecked(&basis2);
        let local_anchor1 = Isometry::from_parts(joint.local_anchor1.coords.into(), quat1);
        let local_anchor2 = Isometry::from_parts(joint.local_anchor2.coords.into(), quat2);

        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
    }
}

impl From<BallJoint> for GenericJoint {
    fn from(joint: BallJoint) -> Self {
        let local_anchor1 = Isometry::new(joint.local_anchor1.coords, na::zero());
        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);
        result
    }
}

impl From<PrismaticJoint> for GenericJoint {
    fn from(joint: PrismaticJoint) -> Self {
        let basis1 = [*joint.local_axis1, joint.basis1[0], joint.basis1[1]];
        let basis2 = [*joint.local_axis2, joint.basis2[0], joint.basis2[1]];
        let quat1 = UnitQuaternion::from_basis_unchecked(&basis1);
        let quat2 = UnitQuaternion::from_basis_unchecked(&basis2);
        let local_anchor1 = Isometry::from_parts(joint.local_anchor1.coords.into(), quat1);
        let local_anchor2 = Isometry::from_parts(joint.local_anchor2.coords.into(), quat2);

        let mut result = Self::new(local_anchor1, local_anchor2);
        result.free_dof(0);
        result.set_dof_limits(0, joint.limits[0], joint.limits[1]);
        result
    }
}

impl From<FixedJoint> for GenericJoint {
    fn from(joint: FixedJoint) -> Self {
        Self::new(joint.local_anchor1, joint.local_anchor2)
    }
}