Best way to use Farseer/Box2D's DebugDraw in Unity3D? - unity3d

Question

Box2D/Farseer 2D physics has a useful component which draws a simple representation of the physics world using primitives (lines, polygons, fills, colors). Here's an example:
What's the best way to accomplish this in Unity3D? Is there a simple way to render polygons with fill, lines, points, etc.? If so, I could implement the interface of DebugDraw with Unity's API, but I'm having trouble finding how to implement primitive rendering like this with Unity.
I understand it'll be in 3D space, but I'll just zero-out one axis and use it basically as 2D.

Answer 1

In case you mean actually a debug box just displayed in the SceneView not in the GameView you can use Gizmos.DrawWireCube
void OnDrawGizmos()
{
//store original gizmo color
var color = Gizmos.color;
// store original matrix
var matrix = Gizmos.matrix;
// set gizmo to local space
Gizmos.matrix = transform.localToWorldMatrix;
// Draw a yellow cube at the transform position
Gizmos.color = Color.yellow;
// here set the scale e.g. for a "almost" 2d box simply use a very small z value
Gizmos.DrawWireCube(transform.position, new Vector3(0.5f, 0.2f, 0.001f));
// restor matrix
Gizmos.matrix = matrix;
// restore color
Gizmos.color = color;
}
you can use OnDrawGizmosSelected to show the Gizmo only if the GameObject is selected
you could also extend this by getting the box size over the inspector
[SerializeField] private Vector3 _boxScale;
and using
Gizmos.DrawWireCube(transform.position, _boxScale);