Modern OpenGL drivers from Nvidia and ATI (and potentially others) support
the new GL_ARB_texture_non_power_of_two extension. This extension very simply
relaxes the restriction that textures created using glTexImage2D() must have
power-of-two dimensions. This requires a very trivial change in our OGL
pipeline and can result in a substantial savings in texture memory.

Consider a 540x540 ARGB image. Without this extension, we must store this image
as a 1024x1024 texture (to meet the pow2 restriction), which requires 4194304
bytes of texture memory. With this extension, we can simply store the image
as a 540x540 texture, which only requires 1166400 bytes of texmem (a 75% savings
in VRAM footprint).