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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 impulse_joints = ImpulseJointSet::new();
let multibody_joints = MultibodyJointSet::new();
/*
* Ground
*/
let ground_size = 200.1;
let ground_height = 0.1;
let rigid_body = RigidBodyBuilder::fixed().translation(vector![0.0, -ground_height, 0.0]);
let handle = bodies.insert(rigid_body);
let collider = ColliderBuilder::cuboid(ground_size, ground_height, ground_size);
colliders.insert_with_parent(collider, handle, &mut bodies);
/*
* Create the cubes
*/
let num = 4000;
let width = 1.0;
let thickness = 0.1;
let colors = [[0.7, 0.5, 0.9], [0.6, 1.0, 0.6]];
let mut curr_angle = 0.0;
let mut curr_rad = 10.0;
let mut prev_angle;
let mut skip = 0;
for i in 0..num {
let perimeter = 2.0 * std::f32::consts::PI * curr_rad;
let spacing = thickness * 4.0;
prev_angle = curr_angle;
curr_angle += 2.0 * std::f32::consts::PI * spacing / perimeter;
let (x, z) = curr_angle.sin_cos();
// Build the rigid body.
let two_pi = 2.0 * std::f32::consts::PI;
let nudged = curr_angle % two_pi < prev_angle % two_pi;
let tilt = if nudged || i == num - 1 { 0.2 } else { 0.0 };
if skip == 0 {
let rot = Rotation::new(Vector::y() * curr_angle);
let tilt = Rotation::new(rot * Vector::z() * tilt);
let position =
Translation::new(x * curr_rad, width * 2.0 + ground_height, z * curr_rad)
* tilt
* rot;
let rigid_body = RigidBodyBuilder::dynamic().position(position);
let handle = bodies.insert(rigid_body);
let collider = ColliderBuilder::cuboid(thickness, width * 2.0, width);
colliders.insert_with_parent(collider, handle, &mut bodies);
testbed.set_initial_body_color(handle, colors[i % 2]);
} else {
skip -= 1;
}
if nudged {
skip = 5;
}
curr_rad += 1.5 / perimeter;
}
/*
* Set up the testbed.
*/
testbed.set_world(bodies, colliders, impulse_joints, multibody_joints);
testbed.look_at(point![100.0, 100.0, 100.0], Point::origin());
}
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