CGA Post-Process BP for UE4
A downloadable asset pack
What is it?
A Blueprint that you can drop into a UE4 game to limit it to 4 colors from the CGA graphics mode palette 0 or palette 1, perfect for #cgajam. The post-processing material is modular and can also be applied to your UMG user interface.
How to use
Download the template (requires Unreal Engine 4.16) and unzip it. You can either open the project directly and migrate the Content/CGAJam folder into your project or drop the whole folder into the templates directory of your 4.16 installation (e.g., C:\Program Files (x86)\Epic Games\UE_4.16\Templates) and then create a new project.
There’s an example map but all of the magic is wrapped up in BP_CGAPostProcess; just drop one into your level and try playing around with the settings to suit your content. You can pick one of the two palettes, adjust how much color-space dithering and screen space dithering there is, and tweak the overall gamma / brightness. For the hand painted environment I found 50% screen dither + 50% LUT dither at level 3 to give me the best results, but for the example scene with solid shapes and color fills, 100% screen dither with no LUT dither looked better.
For more info
Check out my blog post on how it works to see more technical details.