how to efficiently apply multiple shaders

keszegh

so i'd like to add multiple effects stacked on each other on my sprite hierarchy. i can add one shader, render it to a texture, display it, add another shader on that and render it to a texture etc. but this is really slow if the bitmap i work with is full-screen (which it is). is there a better way?
thanks

MoKaLux

I still have to properly learn shaders
In my last attempts I could apply multple shaders to one sprite by multiplying the shaders in the result call.
I don't have the code right now but that was something like:

function shader : shaders() -- bloom ... -- blur ... result = bloom * blur end

Hope this makes sense

keszegh

my shaders are in glsl format btw

hgy29

There’s probably not much you can do since what makes it slow is mainly the gpu usage, except if you can merge some shaders together as @MoKaLux suggested, this will avoid storing pixel to memory and sampling it again for the next pass.

keszegh

by merging you mean guys that i combine the shader codes into one somehow?
in my app i have 7 fx's and maybe more in the future which should be applied in any combination (even more than 2 of them) so there are too many combinations to hard-code them.