Scene/PostProcess Vertex Shader

Hello,

I want apply VertexShader to whole scene.

This is simple Skew shader, how to apply this material to whole scene ?

Insert a material function into every scene material.

I do it before write post but its not handy solution.
It is not possible do it someting like post process ?
In pure OpenGL/DirectX its possible.

For that, you would need to modify base pass vertex shader.

Where I can do it ?
It require modify engine code, or some nodes ?