Pixelizing your 3D game can give it a interesting look and possibly save you time by not having to create all of the pixel art by hand. Combine it with the posterization for a true retro look.
// ...
int pixelSize = 5;
// ...Feel free to adjust the pixel size. The bigger the pixel size, the blockier the image will be.
// ...
float x = int(gl_FragCoord.x) % pixelSize;
float y = int(gl_FragCoord.y) % pixelSize;
x = floor(pixelSize / 2.0) - x;
y = floor(pixelSize / 2.0) - y;
x = gl_FragCoord.x + x;
y = gl_FragCoord.y + y;
// ...The technique works by mapping each fragment to the center of its closest, non-overlapping pixel-sized window. These windows are laid out in a grid over the input texture. The center-of-the-window fragments determine the color for the other fragments in their window.
// ...
fragColor = texture(colorTexture, vec2(x, y) / texSize);
// ...Once you have determined the correct fragment coordinate to use, pull its color from the input texture and assign that to the fragment color.
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