I have a quick webGL effect question.
Say that I want to occasionally apply a webGL effect to everything in the layout, except one object. For example, I want to make everything greyscale except perhaps the HUD, or the player. I also want to have positional control over this effect using a masking object.
If the game has one main layer, I can just use the masking object as expected. Easy. However, if I have multiple parallax / background layers, this becomes very problematic as I now need a large amount of masking objects, all using complex maths to stay with the correct parallax.
Is there any way to make a webGL effect masking object apply its effect 'downwards' to all the layers beneath it? If not, I feel like this would be a great asset to have for the reasons above.
Thanks for your help!