Add a predicate to the DebugRenderBackend to filter out objects that are being rendered

src/pipeline/debug_render_pipeline/debug_render_backend.rs

@@ -1,7 +1,7 @@
 use crate::dynamics::{
     ImpulseJoint, ImpulseJointHandle, Multibody, MultibodyLink, RigidBody, RigidBodyHandle,
 };
-use crate::geometry::Collider;
+use crate::geometry::{Aabb, Collider, ContactPair};
 use crate::math::{Isometry, Point, Real, Vector};
 use crate::prelude::{ColliderHandle, MultibodyJointHandle};
 use na::Scale;
@@ -13,12 +13,14 @@ pub enum DebugRenderObject<'a> {
     RigidBody(RigidBodyHandle, &'a RigidBody),
     /// A collider is being rendered.
     Collider(ColliderHandle, &'a Collider),
+    /// The AABB of a collider is being rendered.
+    ColliderAabb(ColliderHandle, &'a Collider, &'a Aabb),
     /// An impulse-joint is being rendered.
     ImpulseJoint(ImpulseJointHandle, &'a ImpulseJoint),
     /// A multibody joint is being rendered.
     MultibodyJoint(MultibodyJointHandle, &'a Multibody, &'a MultibodyLink),
-    /// Another element is being rendered.
+    /// The contacts of a contact-pair are being rendered.
-    Other,
+    ContactPair(&'a ContactPair, &'a Collider, &'a Collider),
 }
 
 /// Trait implemented by graphics backends responsible for rendering the physics scene.
@@ -28,6 +30,11 @@ pub enum DebugRenderObject<'a> {
 /// `DebugRenderStyle`. The backend is free to apply its own style, for example based on
 /// the `object` being rendered.
 pub trait DebugRenderBackend {
+    /// Predicate to filter-out some objects from the debug-rendering.
+    fn filter_object(&self, _object: DebugRenderObject) -> bool {
+        true
+    }
+
     /// Draws a colored line.
     ///
     /// Note that this method can be called multiple time for the same `object`.

src/pipeline/debug_render_pipeline/debug_render_pipeline.rs

@@ -105,16 +105,19 @@ impl DebugRenderPipeline {
                 if let (Some(co1), Some(co2)) =
                     (colliders.get(pair.collider1), colliders.get(pair.collider2))
                 {
+                    let object = DebugRenderObject::ContactPair(pair, co1, co2);
+
+                    if backend.filter_object(object) {
                         for manifold in &pair.manifolds {
                             for contact in manifold.contacts() {
                                 backend.draw_line(
-                                DebugRenderObject::Other,
+                                    object,
                                     co1.position() * contact.local_p1,
                                     co2.position() * contact.local_p2,
                                     self.style.contact_depth_color,
                                 );
                                 backend.draw_line(
-                                DebugRenderObject::Other,
+                                    object,
                                     co1.position() * contact.local_p1,
                                     co1.position()
                                         * (contact.local_p1
@@ -126,15 +129,23 @@ impl DebugRenderPipeline {
                     }
                 }
             }
+        }
 
         if self.mode.contains(DebugRenderMode::SOLVER_CONTACTS) {
             for pair in narrow_phase.contact_pairs() {
+                if let (Some(co1), Some(co2)) =
+                    (colliders.get(pair.collider1), colliders.get(pair.collider2))
+                {
+                    let object = DebugRenderObject::ContactPair(pair, co1, co2);
+
+                    if backend.filter_object(object) {
                         for manifold in &pair.manifolds {
                             for contact in &manifold.data.solver_contacts {
                                 backend.draw_line(
-                            DebugRenderObject::Other,
+                                    object,
                                     contact.point,
-                            contact.point + manifold.data.normal * self.style.contact_normal_length,
+                                    contact.point
+                                        + manifold.data.normal * self.style.contact_normal_length,
                                     self.style.contact_normal_color,
                                 );
                             }
@@ -142,6 +153,8 @@ impl DebugRenderPipeline {
                     }
                 }
             }
+        }
+    }
 
     /// Render only the joints from the scene.
     pub fn render_joints(
@@ -157,6 +170,10 @@ impl DebugRenderPipeline {
                                 mut anchor_color: [f32; 4],
                                 mut separation_color: [f32; 4],
                                 object| {
+            if backend.filter_object(object) {
+                return;
+            }
+
             if let (Some(rb1), Some(rb2)) = (bodies.get(body1), bodies.get(body2)) {
                 let coeff = if (rb1.is_fixed() || rb1.is_sleeping())
                     && (rb2.is_fixed() || rb2.is_sleeping())
@@ -230,6 +247,7 @@ impl DebugRenderPipeline {
 
             if self.style.rigid_body_axes_length != 0.0
                 && self.mode.contains(DebugRenderMode::RIGID_BODY_AXES)
+                && backend.filter_object(object)
             {
                 let basis = rb.rotation().to_rotation_matrix().into_inner();
                 let coeff = if rb.is_sleeping() {
@@ -262,6 +280,8 @@ impl DebugRenderPipeline {
         if self.mode.contains(DebugRenderMode::COLLIDER_SHAPES) {
             for (h, co) in colliders.iter() {
                 let object = DebugRenderObject::Collider(h, co);
+
+                if backend.filter_object(object) {
                     let color = if let Some(parent) = co.parent().and_then(|p| bodies.get(p)) {
                         let coeff = if parent.is_sleeping() {
                             self.style.sleep_color_multiplier
@@ -290,13 +310,17 @@ impl DebugRenderPipeline {
                     self.render_shape(object, backend, co.shape(), co.position(), color)
                 }
             }
+        }
 
         if self.mode.contains(DebugRenderMode::COLLIDER_AABBS) {
-            for (_, co) in colliders.iter() {
+            for (h, co) in colliders.iter() {
                 let aabb = co.compute_aabb();
                 let cuboid = Cuboid::new(aabb.half_extents());
+                let object = DebugRenderObject::ColliderAabb(h, co, &aabb);
+
+                if backend.filter_object(object) {
                     self.render_shape(
-                    DebugRenderObject::Other,
+                        object,
                         backend,
                         &cuboid,
                         &aabb.center().into(),
@@ -305,6 +329,7 @@ impl DebugRenderPipeline {
                 }
             }
         }
+    }
 
     #[cfg(feature = "dim2")]
     fn render_shape(