thanks to @mikolalysenko for explaining
20:14 < mikolalysenko> basically mip maps were a hack some guy came up with in the 80s to do filtering with variable sized kernels
20:14 < mikolalysenko> it turns out that if you just draw a texture at full resolution some distance away, then you will get these shimmering aliasing
artefacts
20:14 < mikolalysenko> so the solution to this is to just smooth out the texture, so it isn't so noisy
20:15 < mikolalysenko> however the amount you smooth has to be proportional to the distance
20:15 < mikolalysenko> so what a mip pyramid basically is just a collection of filtered images at different down sampled resolutions
20:15 < mikolalysenko> and you can interpolate between them to approximate a blur by a kernel of variable radius