Thank you andres. It works!
I also see now where the error was in my test code. I called pg.filter(shader) outside beginDraw-endDraw.
Now that you have shown how to apply it correctly, it works fine.
I also see now where the error was in my test code. I called pg.filter(shader) outside beginDraw-endDraw.
Now that you have shown how to apply it correctly, it works fine.