1/ why when I load a TGA 24bpp, OpenGL display it in 16bpp ? 2/ why when I use gl_linear to display tex, i cant display tex with width and heigt more than 256x256 ??? (unlike when I use gl_mipmap !)

1/ many reasons (perhaps your esktop is setto 16bit) colour check the internal formats demo on my site
2/ gluBuildMipmaps scales your textures to powers of 2 (prolly scales the largest to 256x256) do u have a voodoo1,2,3 by any chance

http://members.xoom.com/myBollux

1/ my desk is 32bpp
2/ i have a woodoo 3

and then, what can i do for the 1/ and 2/ for resolve it ?

The voodoo 3 does not support a color mode higher than 16-bit. It also does not support textures larger than 256x256. So there is nothing you can do about it besides buying a different card.

*** Triality ***

Oh My God...
So, why my games have 32bpp display ?

I''ve never played a game that doesn''t have support for 16-bit color.

*** Triality ***

Your games appear to look like 32bpp because the Voodoo3 dithers colours up to like 24bpp or so... I used to have a Voodoo3 long ago, and the same thing frustrated me. Buy an nVidia GeForce class card, and then you''ll be set to go. =)