drawing 2D decals aka rendering nodes to framebuffer

Ssyskrank · Sep 19, 2016

Hello everyone. I want to do something like this [ open spoiler ]:

where level geometry is on the left, and the desired effect is on the right So AFAIK I need to setup some texture buffer and shader for the "splatter" thing: 1) render my visible geometry ( TileMap ) to specific framebuffer as bw mask 2) then render the game level normally 3) use prev. created framebuffer to do some simple math in shaders to achieve "overlay" effect with decals. Is that possible? P.S. Maybe it's a general shader question, but I'll post into 2D because I'm dealing with orthogonal stuff.

TwistedTwigleg · Sep 19, 2016

Not sure if this is what you are looking for, but I wrote a shader to mask sprites, or any canvas item, by a single color. I wrote the shader so that I could pull off a similar effect, so maybe it will work for you? Here is a link to the question that holds the shader: link I'm not certain on how you would get the visible geometry into a frame bufffer and convert it to a black and white mask, but outside of that, I think your setup is possible. Hope this helps!

Ssyskrank · Sep 21, 2016

Hi there and thanks for the reply. I think that your approach is very alike to what I want to achieve here but... I've got variable backgrounds and tile textures, actually. So I can not color-mask those out ( it will require too much of uniforms or a fixed pallete within my assets ). But the basic idea is the same, yes. Thats why I'm thinking of creating a framebuffer with a bw mask in it - like it would be possible in a normal OpenGL application, for example. Such technique would allow to get rid of the color variations inside the tiles. And only then I'll be able to apply the same logic as you have prestented in your colormasking shader.