On Mon, Dec 15, 2003 at 07:43:39AM -0600, Stephen J Baker wrote: > But that assumes that alpha is pre-multiplied into the RGB's - which is > not the case for either DirectX or OpenGL's hardware texturing. Both OpenGL and DirectX can handle premultiplied alpha just fine. Just use additive blending and off you go. :-) The problem is of course that you lose a lot of precision when everything has to be stored in 8-bit-per-channel bitmaps after the multiplication. > The standard OpenGL MIPmap generator does not do as you suggest it should. There is no "standard OpenGL mip-map generator". gluBuild2DMipMaps is a part of the GL Utility kit (GLU), not OpenGL, and it usually does its work in software anyhow (quite slowly, and with mediocre quality). You have an OpenGL extension (GL_SGIS_mipmap_generate IIRC) that does automatic filtering, but the exact filtering method is somewhat undefined. /* Steinar */ -- Homepage: http://www.sesse.net/
