Several slides past this, we see an arbitrary function that takes the "area," or in that case, the distance between pixels in the texture space to determine the degree of mini/magni-fication at that pixel, and using that we decide which of the mipmap levels to use.
What is the purpose of footprint area again?
Several slides past this, we see an arbitrary function that takes the "area," or in that case, the distance between pixels in the texture space to determine the degree of mini/magni-fication at that pixel, and using that we decide which of the mipmap levels to use.