Reimar Grabowski wrote:
Hi,
as the title says multisampling does not work for me.
I was testing TOpenGLControl.MultiSampling on Linux (with Radeon GPU),
it worked fine for me.
Note that there is a fallback (documented in TCustomOpenGLControl
interface): if the requested MultiSampling is not available, we fallback
to non-multisampled context (that's because for most applications
anti-aliasing can be just an optional feature). I guess you already
checked that this didn't happen in your case?
The code is pretty straightforward, in glgtkglxcontext.pas
LOpenGLCreateContextCore gets called with given MultiSampling value, and
then CreateOpenGLContextAttrList adds to the attributes this:
Add(GLX_SAMPLE_BUFFERS_ARB); Add(1);
Add(GLX_SAMPLES_ARB); Add(MultiSampling);
The GLX_SAMPLES_ARB is the minimal required value (as
http://www.opengl.org/registry/specs/ARB/multisample.txt says
"...accepts GLX_SAMPLES_ARB in <attribList>, followed by the minimum
number of samples that can be accepted in the multisample buffer"). So
it should work... Well, unless GLX is just lying to us.
Can you check what list was created in your case by
CreateOpenGLContextAttrList, did it contain appropriate GLX_SAMPLES_ARB
and MultiSampling items?
Michalis
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