Implements really simple antialiasing via super-sampling, also known as SSAA.
Antialiasing is often implemented via "FXAA", "TAA", "MSAA", etc. All of these methods are approximations, but they're very fast. FXAA and TAA are basically just really fancy blurs, and MSAA can only smooth polygon edges; pixelated textures are totally missed out on, which is most of what Minecraft is.
Super-sampling is the most pure, accurate, and expensive form of antialiasing. The entire scene is rendered at a higher resolution, and then downscaled for presentation. It's also the easiest to implement.
For example, if you're playing in a 1280×720 window, then QDAA will render the game at 2560×1440 instead, and then resize it to 1280×720 before it's drawn to the screen.
This mod reuses functionality in Minecraft that handles macOS Retina displays, so it should be quite compatible, except with other mods that modify how the framebuffer is drawn to the screen. It also technically optimizes the final render step, replacing a normal quad render with a blit.
Notably, due to how this works, QDAA can even antialias GUIs, improving readability of rotated text and smoothing the edges of 3D item models. Shaders only work on the world.
Note: 1.16 and earlier only sorta work. Only 1.18 and higher is supported.
