Add a character controller implementation

examples3d/newton_cradle3.rs

@@ -0,0 +1,45 @@
+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();
+
+    let radius = 0.5;
+    let length = 10.0 * radius;
+    let rb = RigidBodyBuilder::dynamic();
+    let co = ColliderBuilder::ball(radius).restitution(1.0);
+
+    let n = 5;
+
+    for i in 0..n {
+        let (ball_pos, attach) = (
+            vector![i as Real * 2.2 * radius, 0.0, 0.0],
+            Vector::y() * length,
+        );
+        let vel = if i >= n - 1 {
+            vector![7.0, 0.0, 0.0]
+        } else {
+            Vector::zeros()
+        };
+
+        let ground = bodies.insert(RigidBodyBuilder::fixed().translation(ball_pos + attach));
+        let rb = rb.clone().translation(ball_pos).linvel(vel);
+        let handle = bodies.insert(rb);
+        colliders.insert_with_parent(co.clone(), handle, &mut bodies);
+
+        let joint = SphericalJointBuilder::new().local_anchor2(attach.into());
+        impulse_joints.insert(ground, handle, joint, true);
+    }
+
+    /*
+     * 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());
+}