use std::ops::Range;
use na::{DVector, RealField};
use crate::object::{BodyPartHandle, BodySet};
use crate::solver::{ConstraintSet, GenericNonlinearConstraint, IntegrationParameters,
NonlinearConstraintGenerator};
use crate::solver::helper;
use crate::joint::JointConstraint;
use crate::math::{Point, Vector, DIM};
pub struct BallConstraint<N: RealField> {
b1: BodyPartHandle,
b2: BodyPartHandle,
anchor1: Point<N>,
anchor2: Point<N>,
impulses: Vector<N>,
bilateral_ground_rng: Range<usize>,
bilateral_rng: Range<usize>,
}
impl<N: RealField> BallConstraint<N> {
pub fn new(b1: BodyPartHandle, b2: BodyPartHandle, anchor1: Point<N>, anchor2: Point<N>) -> Self {
BallConstraint {
b1,
b2,
anchor1,
anchor2,
impulses: Vector::zeros(),
bilateral_ground_rng: 0..0,
bilateral_rng: 0..0,
}
}
pub fn set_anchor_1(&mut self, anchor1: Point<N>) {
self.anchor1 = anchor1;
}
pub fn set_anchor_2(&mut self, anchor2: Point<N>) {
self.anchor2 = anchor2;
}
}
impl<N: RealField> JointConstraint<N> for BallConstraint<N> {
fn num_velocity_constraints(&self) -> usize {
DIM
}
fn anchors(&self) -> (BodyPartHandle, BodyPartHandle) {
(self.b1, self.b2)
}
fn velocity_constraints(
&mut self,
_: &IntegrationParameters<N>,
bodies: &BodySet<N>,
ext_vels: &DVector<N>,
ground_j_id: &mut usize,
j_id: &mut usize,
jacobians: &mut [N],
constraints: &mut ConstraintSet<N>,
) {
let body1 = try_ret!(bodies.body(self.b1.0));
let body2 = try_ret!(bodies.body(self.b2.0));
let part1 = try_ret!(body1.part(self.b1.1));
let part2 = try_ret!(body2.part(self.b2.1));
let anchor1 = body1.world_point_at_material_point(part1, &self.anchor1);
let anchor2 = body2.world_point_at_material_point(part2, &self.anchor2);
let assembly_id1 = body1.companion_id();
let assembly_id2 = body2.companion_id();
let first_bilateral_ground = constraints.velocity.bilateral_ground.len();
let first_bilateral = constraints.velocity.bilateral.len();
helper::cancel_relative_linear_velocity(
body1,
part1,
body2,
part2,
assembly_id1,
assembly_id2,
&anchor1,
&anchor2,
ext_vels,
&self.impulses,
0,
ground_j_id,
j_id,
jacobians,
constraints,
);
self.bilateral_ground_rng =
first_bilateral_ground..constraints.velocity.bilateral_ground.len();
self.bilateral_rng = first_bilateral..constraints.velocity.bilateral.len();
}
fn cache_impulses(&mut self, constraints: &ConstraintSet<N>) {
for c in &constraints.velocity.bilateral_ground[self.bilateral_ground_rng.clone()] {
self.impulses[c.impulse_id] = c.impulse;
}
for c in &constraints.velocity.bilateral[self.bilateral_rng.clone()] {
self.impulses[c.impulse_id] = c.impulse;
}
}
}
impl<N: RealField> NonlinearConstraintGenerator<N> for BallConstraint<N> {
fn num_position_constraints(&self, bodies: &BodySet<N>) -> usize {
if self.is_active(bodies) {
1
} else {
0
}
}
fn position_constraint(
&self,
params: &IntegrationParameters<N>,
_: usize,
bodies: &mut BodySet<N>,
jacobians: &mut [N],
) -> Option<GenericNonlinearConstraint<N>> {
let body1 = bodies.body(self.b1.0)?;
let body2 = bodies.body(self.b2.0)?;
let part1 = body1.part(self.b1.1)?;
let part2 = body2.part(self.b2.1)?;
let anchor1 = body1.world_point_at_material_point(part1, &self.anchor1);
let anchor2 = body2.world_point_at_material_point(part2, &self.anchor2);
helper::cancel_relative_translation(params, body1, part1, body2, part2, &anchor1, &anchor2, jacobians)
}
}