Tesbted physx backend: add heightfield, trimesh, and convex mesh support.

src_testbed/engine.rs

@@ -12,7 +12,7 @@ use crate::objects::box_node::Box as BoxNode;
 use crate::objects::heightfield::HeightField;
 use crate::objects::node::{GraphicsNode, Node};
 use rapier::dynamics::{RigidBodyHandle, RigidBodySet};
-use rapier::geometry::{Collider, ColliderHandle, ColliderSet, Shape};
+use rapier::geometry::{ColliderHandle, ColliderSet, Shape};
 //use crate::objects::capsule::Capsule;
 use crate::objects::convex::Convex;
 //#[cfg(feature = "dim3")]