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use na::Point2;
use rapier2d::dynamics::{BallJoint, BodyStatus, JointSet, RigidBodyBuilder, RigidBodySet};
use rapier2d::geometry::{ColliderBuilder, ColliderSet};
use rapier_testbed2d::Testbed;
pub fn init_world(testbed: &mut Testbed) {
/*
* World
*/
let mut bodies = RigidBodySet::new();
let mut colliders = ColliderSet::new();
let mut joints = JointSet::new();
/*
* Create the balls
*/
// Build the rigid body.
// NOTE: a smaller radius (e.g. 0.1) breaks Box2D so
// in order to be able to compare rapier with Box2D,
// we set it to 0.4.
let rad = 0.4;
let numi = 100; // Num vertical nodes.
let numk = 100; // Num horizontal nodes.
let shift = 1.0;
let mut body_handles = Vec::new();
for k in 0..numk {
for i in 0..numi {
let fk = k as f32;
let fi = i as f32;
let status = if i == 0 && (k % 4 == 0 || k == numk - 1) {
BodyStatus::Static
} else {
BodyStatus::Dynamic
};
let rigid_body = RigidBodyBuilder::new(status)
.translation(fk * shift, -fi * shift)
.build();
let child_handle = bodies.insert(rigid_body);
let collider = ColliderBuilder::ball(rad).density(1.0).build();
colliders.insert(collider, child_handle, &mut bodies);
// Vertical joint.
if i > 0 {
let parent_handle = *body_handles.last().unwrap();
let joint = BallJoint::new(Point2::origin(), Point2::new(0.0, shift));
joints.insert(&mut bodies, parent_handle, child_handle, joint);
}
// Horizontal joint.
if k > 0 {
let parent_index = body_handles.len() - numi;
let parent_handle = body_handles[parent_index];
let joint = BallJoint::new(Point2::origin(), Point2::new(-shift, 0.0));
joints.insert(&mut bodies, parent_handle, child_handle, joint);
}
body_handles.push(child_handle);
}
}
/*
* Set up the testbed.
*/
testbed.set_world(bodies, colliders, joints);
testbed.look_at(Point2::new(numk as f32 * rad, numi as f32 * -rad), 5.0);
}
fn main() {
let testbed = Testbed::from_builders(0, vec![("Joints", init_world)]);
testbed.run()
}
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