OpenGL antialiasing isnt working

Question

I'm using the following code in order to antialiase only the edges of my polygons:

glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);
glEnable(GL_POLYGON_SMOOTH);

But it doesn't work.

I can force enable antialiasing by the nvidia control panel, and it does antialiase my application polygons. With the code above, I even enabled blending, but it has no effect. Also the rendering code shouldnt be changed since the nvidia control panel can turn it on, and it certainly cant modify my rendering code, it must be some on/off flag. What is it?

I've heard of "multisampling", but i don't need that.

Edit: the nvidia control panel setting is "application controlled" when it doesnt work.

Answer 1

Have you got the Antialiasing Settings" in the nVidia control panel set to "Application-Controlled"?

Answer 2

It may be that your glEnable call is after the glHint call.

Answer 3

do you create your render context with multisampling? that's what nvidia's control panel changes.

Answer 4

You need to ask for a visual/pixelformat with support for multisampling. This is an attribute in the attribute list you pass to glXChooseFBConfig when using GLX/XLib, and wglChoosePixelformatARB when using the Win32 API. See my post here: http://stackoverflow.com/questions/1513811/getting-smooth-big-points-in-opengl/1513979#1513979

Answer 5

Try enabling blending

glBlendFunc(GL_SRC_ALPHA_SATURATE, GL_ONE);
glEnable(GL_BLEND);
glEnable(GL_POLYGON_SMOOTH);

Also following article might help

http://www.edm2.com/0603/opengl.html

Answer 6

Most likely, your hardware does not support it. Not all OpenGL implementations support antialiased polygons; see the OpenGL FAQ. I've definitely run into this problem before on a first-generation MacBook -- its GPU, the Intel GMA 950, does not support antialiased polygons.