GPU-based raycaster for Unity which raycasts against MeshRenderers, rather than colliders.

This method requires reading from the GPU to CPU and is much slower, but still has its uses.

Call the static function, like you would with Physics.Raycast:

GraphicsRaycast.Raycast(Vector3 origin, Vector3 direction, out RaycastHit hit, float maxDistance, int layerMask = -1);

Optionally, you can draw a gizmo in a similar manner: GraphicsRaycast.DrawGizmo(bool hasHit, Vector3 origin, Vector3 direction, RaycastHit hit, float maxDistance = 25f, float size = 1f);

For it to work in a build, ensure the GraphicRaycastShader.shader file is in the "Always included shaders" list under Graphics Settings. Alternatively, move it into a folder named "Resources".

• Not compatible with any Scriptable Render Pipelines (uses SetReplacementShader)
• Does not work with any geometry drawn through Graphics.DrawMeshInstanced, as these are outside of the regular render loop.
• Does not work with objects using Unlit or Transparent materials, or other shaders not writing to the depth texture.
• Won't work when called through OnSceneGUI (the active render texture apparently cannot be modified during this stage).

Future improvements

• Add override function to raycast from a camera's center. This could simply read the depth- and normals buffer and return the result, and would also work with anything rendered manually through the Graphics API. Very useful for a Depth of Field auto-focus function.

MIT License (see LICENSE)