How to visualize PhysicsWorld / CollisionShape with debug renderer? - urhosharp

Question

My test scene for Urho3D/Urhosharp contains two boxes (see screenshot).
For both, the red and the green box I added a RigidBody and a CollisionShape.
The shape for the red box is a sphere and for the blue one a box. I've enabled debug visualisation by adding:
app.Engine.SubscribeToPostRenderUpdate(args => {
app.Renderer.DrawDebugGeometry(false);
});
However, this does not render the collision shapes but only the wireframe of the objects (green lines).
Here's the code for the blue node:
var floorNode = app.RootNode.CreateChild("Floor");
floorNode.Position = Vector3.Zero;
floorNode.Scale = new Vector3(10, 1, 10);
var floorComp = floorNode.CreateComponent<Box>();
floorComp.SetMaterial(Material.FromColor(new Color(0, 0, 1, 0.5f)));
var rigidBody = floorNode.CreateComponent<RigidBody>();
rigidBody.Mass = 0;
var collNode = floorNode.CreateComponent<CollisionShape>();
collNode.SetBox(Vector3.One, Vector3.Zero, Quaternion.Identity);
And for the red one:
var boxNode = app.RootNode.CreateChild("Box");
boxNode.SetScale(2f);
var boxComp = boxNode.CreateComponent<Box>();
boxComp.Color = Color.Red;
boxComp.SetMaterial(Material.FromColor(Color.Red));
var rigidBody = boxNode.CreateComponent<RigidBody>();
rigidBody.Mass = 0f;
var collNode = boxNode.CreateComponent<CollisionShape>();
collNode.SetBox(Vector3.One, Vector3.Zero, Quaternion.Identity);
collNode.SetSphere(3f, Vector3.Zero, Quaternion.Identity);
The collision works but I'd love to see the physics world because it makes it easier to experiment.

Answer 1

And here's the solution: the default debug output of the Urho3D renderer does not include the physics components. It has to be added manually.
app.Engine.SubscribeToPostRenderUpdate(args => {
// Default debug rendering.
app.Renderer.DrawDebugGeometry(false);
// Use debug renderer to output physics world debug.
var debugRendererComp = app.Scene.GetComponent<DebugRenderer>();
var physicsComp = app.Scene.GetComponent<PhysicsWorld>();
if(physicsComp != null)
{
physicsComp.DrawDebugGeometry(debugRendererComp, false);
}
});
For this to work the scene must of course have a debug renderer and a physics component:
app.Scene.GetOrCreateComponent<PhysicsWorld>();
app.Scene.GetOrCreateComponent<DebugRenderer>();
Then the result is as expected. In the image below the red box has got a spherical collision shape:
The nice thing I noticed: since the collision shape is a child node of the actual node it will scale together with the node. This means if the box or sphere (or whatever) is created with a size of Vector3.One it will always match the actual node size.