Shader - How to begin

[daerlnaxe]

Hi,

I would learn how to work easily with shader (futhermore english is not my native language). I don't understand how it works, i saw there is an entry point but that's all.

I tried to look at example on a website specialized on shaders, but i don't know how to adapt for PICOM neither, how to begin with picom for shaders.

My purpose is to do a basical scanline/crt effect, with a common program i must probably get number of lines on the screen and draw above, a line all the X lines. But here i can't see.