What is this (unwanted) blur/antialiasing effect that I have in the game engine? The effect worsen with the distance from the camera. Also, it seems to increase in a discrete (not continuous) manner. It also affects my bumping maps. I tried to change the AA setting but it didn't work.
This is related to mipmap settings, you can change in user preferences > systems > mipmap
But this only work inside blender.
In game (standalone) you need a script.
from bge import render render.setMipmapping(0)
related: Python API