Materials: Check if you're rendering orthographic or perspective

Per discord user Blueberry_pie:

posting this here in case its useful for others: if you want to know whether your material is being rendered with perspective or orthographic projection, add a custom node with the output type CMOT Float 1 and the following code: View.ViewToClip[3][3] less than 1.0f. this will return 1 for perspective and 0 for ortho