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use rapier3d::prelude::*;
use rapier_testbed3d::Testbed;
pub fn init_world(testbed: &mut Testbed) {
/*
* World
*/
let mut bodies = RigidBodySet::new();
let mut colliders = ColliderSet::new();
let mut impulse_joints = ImpulseJointSet::new();
let multibody_joints = MultibodyJointSet::new();
/*
* Fixed ground to attach one end of the joints.
*/
let rigid_body = RigidBodyBuilder::fixed();
let ground_handle = bodies.insert(rigid_body);
/*
* Spring joints with a variety of spring parameters.
* The middle one has uses critical damping.
*/
let num = 30;
let radius = 0.5;
let mass = Ball::new(radius).mass_properties(1.0).mass();
let stiffness = 1.0e3;
let critical_damping = 2.0 * (stiffness * mass).sqrt();
for i in 0..=num {
let x_pos = -6.0 + 1.5 * i as f32;
let ball_pos = point![x_pos, 4.5, 0.0];
let rigid_body = RigidBodyBuilder::dynamic()
.translation(ball_pos.coords)
.can_sleep(false);
let handle = bodies.insert(rigid_body);
let collider = ColliderBuilder::ball(radius);
colliders.insert_with_parent(collider, handle, &mut bodies);
let damping_ratio = i as f32 / (num as f32 / 2.0);
let damping = damping_ratio * critical_damping;
let joint = SpringJointBuilder::new(0.0, stiffness, damping)
.local_anchor1(ball_pos - Vector::y() * 3.0);
impulse_joints.insert(ground_handle, handle, joint, true);
// Box that will fall on to of the springed balls, makes the simulation funier to watch.
let rigid_body =
RigidBodyBuilder::dynamic().translation(ball_pos.coords + Vector::y() * 5.0);
let handle = bodies.insert(rigid_body);
let collider = ColliderBuilder::cuboid(radius, radius, radius).density(100.0);
colliders.insert_with_parent(collider, handle, &mut bodies);
}
/*
* Set up the testbed.
*/
testbed.set_world_with_params(
bodies,
colliders,
impulse_joints,
multibody_joints,
vector![0.0, -9.81, 0.0],
(),
);
testbed.look_at(point![15.0, 5.0, 42.0], point![13.0, 1.0, 1.0]);
}
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