Some shaders don't render properly when Canvas Renderer is installed

[mclegoman]

Canvas Renderer breaks some shaders.

I've only done a little bit of testing, but this includes:

• all depth shaders
• minecraft:scan_pincushion

With Canvas Renderer Installed:

Canvas Shader: Lumi Lights 1x and Souper Secret Settings Shader: extended_shaders:out_of_bounds:

Canvas Shader: Lumi Lights 1x and Souper Secret Settings Shader: minecraft:scan_pincushion:

Without Canvas Renderer Installed:

Souper Secret Settings Shader: extended_shaders:out_of_bounds:

Souper Secret Settings Shader: minecraft:scan_pincushion:

[Nettakrim]

i think scan pincushion has that weird passthrough effect because it uses discard instead of setting the color to black (see https://github.com/InventivetalentDev/minecraft-assets/blob/1.20.2/assets/minecraft/shaders/program/scan_pincushion.fsh#L48), as for why canvas renderer would act differently here i have no idea

depth shaders likely break because of the hacky depth fix, which is interesting

from my experience various combinations of presseing F1, looking at blocks, and using fast/fancy/fabulous graphics can also sometimes have an effect on if a shader works properly, making thourough testing a bit of a pain