GL_GENERATE_MIPMAP vs gluBuild2DMipmaps

GL_GENERATE_MIPMAP is useful when you have dynamic textures. But the new GenerateMipmapEXT() is better to use than GL_GENERATE_MIPMAP.

gluBuild2DMipmaps() is done with your CPU vs. GPU like above to setup your mipmap chain.

If you just want to have mipmapped textures gluBuild2DMipmaps() is just fine.

I there any way to confirm that mipmapping is working when GL_GENERATE_MIPMAP is used? I get different (fail) behavior between this and gluBuild2Dmipmaps as follows:
With the gluBuild2DMipmaps function, in a program where one of the textures is with non-power-of-two dimensions (program has with alpha blending if it matters), with a Release build that texture doesn't display. With GL_GENERATE_MIPMAP it does.

gluBuild2DMipmaps is very slow (+ buggy)

if a texture is not power of 2 sized then gluBuild2DMipmaps will first resize it so it is, i assume thats where the problem lies somehow.

to artifically see if mipmapping is working draw the texture with a high texture_lod_bias
perhaps draw the texture on a fullscreen sized polygon
+ then with a keypress cycle through the mipmap levels

If you want to use the GL_GENERATE_MIPMAP you don't use gluBuild2DMipmaps() you use glTexImage2D() and call the correct glTexParameteri() with true in it.

The above method works, and will automatically generate mipmaps for your dynamic textures for all levels above base level.

With GenerateMipmapEXT() it will generate all mipmaps above base also but when you choose to not the driver.