Fix #378 Added one example join_motor_position

examples2d/joint_motor_position2.rs

@@ -0,0 +1,46 @@
+use rapier2d::prelude::*;
+use rapier_testbed2d::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();
+
+    /*
+     * The ground
+     */
+    let ground_size = 5.0;
+    let ground_height = 0.1;
+
+    let rigid_body = RigidBodyBuilder::fixed().translation(vector![0.0, -ground_height]);
+    let ground_handle = bodies.insert(rigid_body);
+    let collider = ColliderBuilder::cuboid(ground_size, ground_height);
+    colliders.insert_with_parent(collider, ground_handle, &mut bodies);
+
+    /*
+     * A rectangle on a motor
+     */
+    for num in 0..9 {
+        let x_pos = -6.0 + 1.5 * num as f32; 
+        let rigid_body = RigidBodyBuilder::dynamic().translation(vector![x_pos, 2.0]);
+        let handle = bodies.insert(rigid_body);
+        let collider = ColliderBuilder::cuboid(0.1, 0.5);
+        colliders.insert_with_parent(collider, handle, &mut bodies);
+
+        let joint = RevoluteJointBuilder::new()
+            .local_anchor2(point![x_pos, 1.5])
+            .local_anchor1(point![0.0, -0.5])
+            .motor_position(std::f32::consts::PI/4.0*num as f32, 100.0, 15.0);
+        impulse_joints.insert(handle,ground_handle, joint, true);
+    }
+
+    /*
+     * Set up the testbed.
+     */
+    testbed.set_world_with_params(bodies, colliders, impulse_joints, multibody_joints,vector![0.0,0.0],());
+    testbed.look_at(point![0.0, 0.0], 40.0);
+}