Just published a <deeper dive> into the shader-bas...

# compose-desktop

[Kirill Grouchnikov]

Just published a deeper dive into the shader-based render effects in Compose Desktop / Skiko, looking at each step one at a time and detailing all the moving parts.

[romainguy]

You can try to get syntax highlighting by installing the GLSL plugin and using the @Language annotation

[romainguy]

Other note: Skia shaders work in linear space, you should take the luminance of the noise instead of the luma (just different coefficients)

[romainguy]

Also if you wanted to just kill banding without adding a strong visible noise you can dither the content by adding +/-1/255 using a procedural noise pattern. For instance: https://github.com/google/filament/blob/main/shaders/src/dithering.fs

[romainguy]

For desktop the RGB triangle noise would work great

[romainguy]

In your case you wouldn't use the temporal component though

[Kirill Grouchnikov]

Thanks. Updated to use luminance. Also installed https://plugins.jetbrains.com/plugin/6993-glsl-support and added @Language("GLSL") to the snippets. Looks pretty decent.

[romainguy]

I just realized something else. I should write a blog post on shader tips and tricks because SkSL/AGSL makes it too easy to mix type precisions if you are not aware, which is not ideal.

[Kirill Grouchnikov]

It's a bit confusing since it allows you to mix half4 and vec4 with no warnings

[romainguy]

vec4 will be like half4, at least on Android

[romainguy]

but float won’t be, so you should use half