Add comments.

3 files changed, 129 insertions, 1 deletions

diff --git a/examples3d/all_examples3.rs b/examples3d/all_examples3.rs
index 2611a2f..8031814 100644
--- a/examples3d/all_examples3.rs
+++ b/examples3d/all_examples3.rs
@@ -25,6 +25,7 @@ mod debug_friction3;
 mod debug_infinite_fall3;
 mod debug_prismatic3;
 mod debug_rollback3;
+mod debug_shape_modification3;
 mod debug_triangle3;
 mod debug_trimesh3;
 mod domino3;
@@ -112,6 +113,10 @@ pub fn main() {
         ("(Debug) infinite fall", debug_infinite_fall3::init_world),
         ("(Debug) prismatic", debug_prismatic3::init_world),
         ("(Debug) rollback", debug_rollback3::init_world),
+        (
+            "(Debug) shape modification",
+            debug_shape_modification3::init_world,
+        ),
     ];
 
     // Lexicographic sort, with stress tests moved at the end of the list.
diff --git a/examples3d/debug_shape_modification3.rs b/examples3d/debug_shape_modification3.rs
new file mode 100644
index 0000000..7ec06dd
--- /dev/null
+++ b/examples3d/debug_shape_modification3.rs
@@ -0,0 +1,123 @@
+use na::{Isometry3, Point3, Vector3};
+use rapier3d::dynamics::{JointSet, RigidBodyBuilder, RigidBodySet};
+use rapier3d::geometry::{ColliderBuilder, ColliderSet, SharedShape};
+use rapier_testbed3d::Testbed;
+
+pub fn init_world(testbed: &mut Testbed) {
+    /*
+     * World
+     */
+    let mut bodies = RigidBodySet::new();
+    let mut colliders = ColliderSet::new();
+    let joints = JointSet::new();
+    /*
+     * Ground.
+     */
+    let ground_size = 20.0;
+    let ground_height = 0.1;
+
+    let rigid_body = RigidBodyBuilder::new_static()
+        .translation(0.0, -ground_height, 0.0)
+        .build();
+    let ground_handle = bodies.insert(rigid_body);
+    let collider = ColliderBuilder::cuboid(ground_size, ground_height, ground_size)
+        .friction(0.15)
+        // .restitution(0.5)
+        .build();
+    colliders.insert(collider, ground_handle, &mut bodies);
+
+    /*
+     * Rolling ball
+     */
+    let ball_rad = 0.1;
+    let rb = RigidBodyBuilder::new_dynamic()
+        .translation(0.0, 0.2, 0.0)
+        .linvel(10.0, 0.0, 0.0)
+        .build();
+    let ball_handle = bodies.insert(rb);
+    let collider = ColliderBuilder::ball(ball_rad).density(100.0).build();
+    let ball_coll_handle = colliders.insert(collider, ball_handle, &mut bodies);
+
+    let mut linvel = Vector3::zeros();
+    let mut angvel = Vector3::zeros();
+    let mut pos = Isometry3::identity();
+    let mut step = 0;
+    let snapped_frame = 51;
+
+    testbed.add_callback(move |_, _, physics, _, _| {
+        step += 1;
+
+        // Snap the ball velocity or restore it.
+        let ball = physics.bodies.get_mut(ball_handle).unwrap();
+
+        if step == snapped_frame {
+            linvel = *ball.linvel();
+            angvel = *ball.angvel();
+            pos = *ball.position();
+        }
+
+        if step == 100 {
+            ball.set_linvel(linvel, true);
+            ball.set_angvel(angvel, true);
+            ball.set_position(pos, true);
+            step = snapped_frame;
+        }
+
+        let ball_coll = physics.colliders.get_mut(ball_coll_handle).unwrap();
+        ball_coll.set_shape(SharedShape::ball(ball_rad * step as f32 * 2.0));
+    });
+
+    /*
+     * Create the primitives
+     */
+    let num = 8;
+    let rad = 1.0;
+
+    let shiftx = rad * 2.0 + rad;
+    let shifty = rad * 2.0 + rad;
+    let shiftz = rad * 2.0 + rad;
+    let centerx = shiftx * (num / 2) as f32;
+    let centery = shifty / 2.0;
+    let centerz = shiftz * (num / 2) as f32;
+
+    let mut offset = -(num as f32) * (rad * 2.0 + rad) * 0.5;
+
+    for j in 0usize..20 {
+        for i in 0..num {
+            for k in 0usize..num {
+                let x = i as f32 * shiftx - centerx + offset + 5.0;
+                let y = j as f32 * shifty + centery + 3.0;
+                let z = k as f32 * shiftz - centerz + offset;
+
+                // Build the rigid body.
+                let rigid_body = RigidBodyBuilder::new_dynamic().translation(x, y, z).build();
+                let handle = bodies.insert(rigid_body);
+
+                let collider = match j % 5 {
+                    0 => ColliderBuilder::cuboid(rad, rad, rad).build(),
+                    1 => ColliderBuilder::ball(rad).build(),
+                    // Rounded cylinders are much more efficient that cylinder, even if the
+                    // rounding margin is small.
+                    2 => ColliderBuilder::round_cylinder(rad, rad, rad / 10.0).build(),
+                    3 => ColliderBuilder::cone(rad, rad).build(),
+                    _ => ColliderBuilder::capsule_y(rad, rad).build(),
+                };
+
+                colliders.insert(collider, handle, &mut bodies);
+            }
+        }
+
+        offset -= 0.05 * rad * (num as f32 - 1.0);
+    }
+
+    /*
+     * Set up the testbed.
+     */
+    testbed.set_world(bodies, colliders, joints);
+    testbed.look_at(Point3::new(10.0, 10.0, 10.0), Point3::origin());
+}
+
+fn main() {
+    let testbed = Testbed::from_builders(0, vec![("Boxes", init_world)]);
+    testbed.run()
+}
diff --git a/examples3d/primitives3.rs b/examples3d/primitives3.rs
index db15341..2711ba9 100644
--- a/examples3d/primitives3.rs
+++ b/examples3d/primitives3.rs
@@ -25,7 +25,7 @@ pub fn init_world(testbed: &mut Testbed) {
     colliders.insert(collider, handle, &mut bodies);
 
     /*
-     * Create the cubes
+     * Create the primitives
      */
     let num = 8;
     let rad = 1.0;