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yaro_dup1
02-04-2003, 08:21 AM
Hi,

Is there any way to turn on antialiasing in OpenGL without using extensions?

thanks

mdog1234
02-04-2003, 08:25 AM
You need to enable anti-aliasing for points or lines using
glEnable( GL_POINT_SMOOTH or GL_LINE_SMOOTH )
Since anti-aliasing uses the alpha values, you also need enabled blending glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
glEnable( GL_BLEND )
Anti-aliasing polygons is a bit more complex.

[This message has been edited by mdog1234 (edited 02-04-2003).]

Mazy
02-04-2003, 08:31 AM
if you mean FSAA then you have to use extensions, or atleast something more than opengl1.1 ( wich in windows will be like extensions)

HalcyonBlaze
02-04-2003, 08:40 AM
Is it possible to do full screen anti aliasing using the accumulation buffer? I mean you could render the main scene, and then render it again with very very small jitters to create a somewhat blurred edge?

- Halcyon

mdog1234
02-04-2003, 08:47 AM
Yeah using the accum buffer is another way but it slows down your performance a great deal.

HalcyonBlaze
02-04-2003, 12:39 PM
If you were to render the scene to the accumulation buffer n times, should you expect the fps to drop by n times? Or does OpenGL do anything to avoid such a problem?

- Halcyon

Mazy
02-04-2003, 03:01 PM
Its often MUCH slower than that becourse the accum buffer isnt often in hardware, so the driver reads teh framebuffer and puts it into the system memory for each add, and makes all the calculations with the cpu, and last copies it all back to the framebuffer.. we're talking about 1-2 fps here.