When the viewport is not fullscreen, the view is cropped and distorted after applying a shader.
This is due to using SCREEN_UV (meant for SCREEN_TEXTURE) instead of UV (meant for TEXTURE).
Fix punctuation in custom_postprocessing.
I surmise that the second ``col += texture(TEXTURE, SCREEN_UV + SCREEN_PIXEL_SIZE.xy).xyz;`` line was missing a ``-`` (minus sign) before I went through it.
If so, I chalk it up to a case of copypasta.
4-space is our convention for indented blocks and should be used consistently.
The only exception is for C++ code which is tab-indented, as the engine code.
Beuc