Hello everyone,
using OpenGL (and C in Linux-Debian) i want to add additional clipping planes to a scene by glClipPlane(GL_CLIP_PLANE0, eqn) and glEnable(GL_CLIP_PLANE0).
The first thing i noticed: nothing is clipped/changed.
Because of this, i tried the example code from the corresponding chapter in the
opengl-redbook. I added two lines of info-output to the
clippingTest.
This test renders a wireframe sphere and clips three fourth of it away - you should see only the fourth part of the full sphere. I compiled and ran this in windows, there it works as expected (
screenshot in windows,
screenshot in linux).
Can anyone verify this behaviour ? Now, i'm wondering if my setup is buggy or xorg is buggy or i am buggy.
The info-output in windows (mingw) is
Code:
$ gcc clippingTest.c -o clippingTest -lglut32 -lopengl32 -lglu32 -lm && ./clippingTest.exe
Maximum count of additional clip-planes: 6
Depth bits: 16
the output in linux is
Code:
$ gcc -lGLU -lGL -lglut -lm clippingTest.c -o clippingTest && ./clippingTest
libGL warning: 3D driver claims to not support visual 0x4b
Maximum count of additional clip-planes: 6
Depth bits: 24
I suspect the above error about 'visual 0x4b' has something to do with it. But i didn't find anything useful regarding clipping in the web.
Can someone tell me, what 'visual 0x4b' is ? (and all the other visuals listed in my
xorg.log)
I'm using Debian (unstable) with kernel 2.6.17.6, xorg 7.1.1 and an ati radeon9700 card. The hardware acceleration seems to work (opensource/xorg driver).
glxinfo
Little background: The last assignment in my actual computer graphics course was about simulating the perspective transformed canonical viewing volume (cube with extrema [-1,-1,-1] and [1,1,1]) and its clipping on six sides (which is usually done by opengl on the frustum automagically).
Can anyone give me an hint or can tell me someone who can ?
thanks for reading,
cdex.
