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Old 01-15-07, 12:26 PM   #4
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Join Date: Feb 2003
Location: St. Petersburg, Russia
Posts: 20
Default Re: Antialiasing in GL contexts

Originally Posted by squeen
the columns 'ns' and 'b' under 'ms' in glxinfo are the number of samples and buffers with multisample visuals. On Quadro FX 5500 cards I get ones like 16 1 and 8 1, for 'ms' and 'b' respectively. However, you point is right, even if you get a multisample visual with fbconfig, that's not enough like it was on the older SGI/IRIX system, you also need the environment variable set telling it which type of multisample you want to use (I prefer 7, 4x supersample, 4x multi).
Hmm, strange, I don't get any of such modes in glxinfo output. Both 'ns' and 'b' are 0 in glxinfo output for all visuals (both on my dust-old GeForce 440MX as well on a newer GeForce 6200, drivers 9631), however multisampling for sure works with the environment variable. Thus I never was able to get an supersampled fbconfig.

The type of multisample you're talking about should be, as far as I understand, the 'ms' parameter. In the specs for the GLX_ARB_multisample extension it's said that "GLX_SAMPLES_ARB" is a vendor-specific parameter, so I assume it's the same as the __GL_FSAA_MODE env var.

Originally Posted by squeen
The OpenGL call, glEnable( GL_MULTISAMPLE ) also seems to have no effect, nor does glHint(GL_MULTISAMPLE_FILTER_HINT_NV, GL_NICEST) that I've detected.
The glHint is told only to give a hint to the rendering system whenever you want more accurate or more fast rendering, but in any case multisample rendering should be enabled by glEnable().

Originally Posted by Thunderbird
From my experience multisampling works fine as long as both the GLX context and the drawable you use have multisampling support. Though not all modes advertised in nvidia-settings are offered but it still works.
Hmm, what means "drawable has multisampling support"? The only place where I can request multisampling is in the GL context, but the X Window has no such attribute as "support for multisampling".

Last edited by zap; 01-15-07 at 12:39 PM.
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