Minecraft has in recent snapshots greatly improved the capabilities of its shader system, now allowing postprocessing shaders “post effects” to be applied using commands. This has wildly changed what is now possible in vanilla minecraft and I immediately was overcome with excitement about what was now possible. After playing around with it for a while and discovering the “persistent” mode on custom render targets, I realized that even more than expected was now possible, and found a way to make posteffects that have fade-in animations by updating the value in a persistent render target over the course of a few frames. To make it consistent across different frame rates, I had to figure out a way to get a deltatime (time between frames), which I was able to do using the GameTime uniform in minecraft.

Having gotten a deltatime, I began wondering about the possibilities of creating a fully functional game contained entirely in a minecraft postprocessing shader…