I have minor trouble understanding in what way mipmaping works for NPOT textures.
According to the reference each mipmap level size for 2d textures is
mipmapSizeX = max(1, floor(textureSizeX / pow(2, mipmapLevel)))
mipmapSizeY = max(1, floor(textureSizeY / pow(2, mipmapLevel)))
So for a 128x128 texture, the mipmap level 1 size would be 64x64.
And for a 127x127 texture, it would be 63x63.
Because there is no direct 4 to 1 mapping of the textels anymore, I suppose it just gets blitted with a linear filter, is that correct?
Does the fetching of the mipmap level 1 then exactly work like fetching from a 63x63 texture? I mean in the context of normalized texCoords to texel positions.