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