feat: add a few more debug demos

examples2d/all_examples2.rs

@@ -15,6 +15,7 @@ mod collision_groups2;
 mod convex_polygons2;
 mod damping2;
 mod debug_box_ball2;
+mod debug_total_overlap2;
 mod drum2;
 mod heightfield2;
 mod joint_motor_position2;
@@ -82,6 +83,7 @@ pub fn main() {
         ("Trimesh", trimesh2::init_world),
         ("Joint motor position", joint_motor_position2::init_world),
         ("(Debug) box ball", debug_box_ball2::init_world),
+        ("(Debug) total overlap", debug_total_overlap2::init_world),
     ];
 
     // Lexicographic sort, with stress tests moved at the end of the list.

examples2d/debug_total_overlap2.rs

@@ -0,0 +1,28 @@
+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 impulse_joints = ImpulseJointSet::new();
+    let multibody_joints = MultibodyJointSet::new();
+
+    // Build many balls, all spawned at the same point.
+    let rad = 0.5;
+
+    for _ in 0..100 {
+        let rigid_body = RigidBodyBuilder::dynamic();
+        let handle = bodies.insert(rigid_body);
+        let collider = ColliderBuilder::cuboid(rad, rad);
+        colliders.insert_with_parent(collider, handle, &mut bodies);
+    }
+
+    /*
+     * Set up the testbed.
+     */
+    testbed.set_world(bodies, colliders, impulse_joints, multibody_joints);
+    testbed.look_at(point![0.0, 0.0], 50.0);
+}