Re: Number of mipmaps in a mipmap texture?

[Frank C. <dev...@ch...>]

On 18-Dec-04, at 12:17 PM, James W. Walker wrote:

> On Dec 18, 2004, at 12:41 AM, Jose' Cruanyes wrote:
>
>> but why we have to go down to a 1*1 texture?
>
> That's what OpenGL does. For instance, in the description of 
> gluBuild2DMipmaps, the reference manual says "For example, if width is 
> 64 and height is 16, the following mipmaps are built: 64x16, 32x8, 
> 8x2, 4x1, 2x1, and 1x1".

OpenGL also requires all those levels, and will replace missing mipmaps 
with solid white textures. Apple didn't follow the spec for their CFM 
OpenGL implementation however (it reverts to a linear filter when 
mipmaps are missing), so this might not be obvious unless you're 
working in Win32/*nix or MachO.

Frank.