From: Alexander Lechner (alexander.lechner++at++vertigo-systems.de)
Date: 07/06/2004 18:04:20
Hi all!
I discovered some problems when using CubeTextures and Performer 3.1.1 Demo on
Linux.
(1) Trace output of an OpenGL debugger shows that Performer uses
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, 1);
for a CubeTexture, but I think the target must rather be
GL_TEXTURE_CUBE_MAP instead of GL_TEXTURE_2D
(2) The man page states that cube images are specified in the order
minx,maxx,miny,maxy,minz,maxz. This seems not correct, as textures are
downloaded in the following order by Performer:
glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB, 0, 32849, 512, 512, 0,
GL_RGB, GL_UNSIGNED_BYTE, pixels);
glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_X_EXT, 0, 32849, 512, 512, 0,
GL_RGB, GL_UNSIGNED_BYTE, pixels);
glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB, 0, 32849, 512, 512, 0,
GL_RGB, GL_UNSIGNED_BYTE, pixels);
glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_EXT, 0, 32849, 512, 512, 0,
GL_RGB, GL_UNSIGNED_BYTE, pixels);
glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Z, 0, 32849, 512, 512, 0, GL_RGB,
GL_UNSIGNED_BYTE, pixels);
glTexImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_EXT, 0, 32849, 512, 512, 0,
GL_RGB, GL_UNSIGNED_BYTE, pixels);
I verified this with my own code and also with cube map example of Performer
pguide.
(3) Automatic mipmapping does not work with CubeTextures. There is no call or
a parameter set by Performer.
Also, why does Performer not use
glTexParameteri(target, GL_GENERATE_MIPMAP_SGIS, GL_TRUE);
if the hardware supports it. Always uses gluBuild2DMipmaps instead (except
when using CubeMaps).
Thanks in advance!
Alex
-- Alexander.Lechner ++at++ vertigo-systems.de Engelbertstraße 30 | phone: +49-221-2405472 D-50674 Köln | fax: +49-221-34892616
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