nphysics2d/joint/
fixed_joint.rs

1use na::{DVectorSliceMut, RealField};
2
3use crate::joint::Joint;
4
5use crate::math::{Isometry, JacobianSliceMut, Translation, Vector, Velocity};
6use crate::solver::IntegrationParameters;
7
8/// A joint that does not allow any relative degrees of freedom.
9#[derive(Copy, Clone, Debug)]
10pub struct FixedJoint<N: RealField + Copy> {
11    body_to_parent: Isometry<N>,
12}
13
14impl<N: RealField + Copy> FixedJoint<N> {
15    /// Create a joint that does not a allow any degrees of freedom between two multibody links.
16    ///
17    /// The descendent attached to this joint will have a position maintained to `pos_wrt_body`
18    /// relative to its parent.
19    pub fn new(pos_wrt_body: Isometry<N>) -> Self {
20        FixedJoint {
21            body_to_parent: pos_wrt_body.inverse(),
22        }
23    }
24}
25
26impl<N: RealField + Copy> Joint<N> for FixedJoint<N> {
27    fn ndofs(&self) -> usize {
28        0
29    }
30
31    fn body_to_parent(&self, parent_shift: &Vector<N>, body_shift: &Vector<N>) -> Isometry<N> {
32        let parent_trans = Translation::from(*parent_shift);
33        let body_trans = Translation::from(*body_shift);
34        parent_trans * self.body_to_parent * body_trans
35    }
36
37    fn update_jacobians(&mut self, _: &Vector<N>, _: &[N]) {}
38
39    fn jacobian(&self, _: &Isometry<N>, _: &mut JacobianSliceMut<N>) {}
40
41    fn jacobian_dot(&self, _: &Isometry<N>, _: &mut JacobianSliceMut<N>) {}
42
43    fn jacobian_dot_veldiff_mul_coordinates(
44        &self,
45        _: &Isometry<N>,
46        _: &[N],
47        _: &mut JacobianSliceMut<N>,
48    ) {
49    }
50
51    fn integrate(&mut self, _: &IntegrationParameters<N>, _: &[N]) {}
52    fn apply_displacement(&mut self, _: &[N]) {}
53
54    fn jacobian_mul_coordinates(&self, _: &[N]) -> Velocity<N> {
55        Velocity::zero()
56    }
57
58    fn jacobian_dot_mul_coordinates(&self, _: &[N]) -> Velocity<N> {
59        Velocity::zero()
60    }
61
62    fn default_damping(&self, _: &mut DVectorSliceMut<N>) {}
63
64    #[inline]
65    fn clone(&self) -> Box<dyn Joint<N>> {
66        Box::new(*self)
67    }
68}
nphysics2d/joint/fixed_joint.rs

nphysics2d/joint/
fixed_joint.rs
