Multisampling on Matrox card

support
1

simcamil84 wrote on Wednesday, May 11, 2011:

Hello,

I’ve switched from GLUT to GLFW because I needed multisampling and GLUT
doesn’t have it.

I have activated multisampling on my app using:

	glfwOpenWindowHint(GLFW_FSAA_SAMPLES, 4);

It works fine on a computer with an nvidia card (I have the nvidia
AntiAliasing setting set as “Application controlled”). The problem is that I
have another computer with a Matrox card and it doesn’t work. The Matrox card
is new and it should support AA up to 16x.

Is there something else I have to do in my code? Do the Matrox cards have
something different?

Thank you

2

elmindreda wrote on Wednesday, May 11, 2011:

You shouldn’t have to do anything different.

Does the driver expose the necessary extensions?

3

simcamil84 wrote on Wednesday, May 11, 2011:

What do you mean? How do I check that?

4

elmindreda wrote on Wednesday, May 11, 2011:

You need the GL_ARB_multisample, WGL_ARB_multisample and
WGL_ARB_pixel_format extensions.

One way is to use GLview. http://www.realtech-vr.com/glview/

5

simcamil84 wrote on Wednesday, May 11, 2011:

I have checked and I do have those 3 extensions.

The only difference I see with my other computer is that the matrox card uses
opengl 2.0 and the nvidia card 3.3. This shouldn’t be a problem since
multisample was introduced in opengl 1.3.

What else can I check?

Thank you

6

elmindreda wrote on Wednesday, May 11, 2011:

What is the value of GLFW_FSAA_SAMPLES after the window has been created?

7

simcamil84 wrote on Wednesday, May 11, 2011:

On the computer that works fine the value is 4.

On the computer that doesn’t work (matrox) the value is 0.

8

elmindreda wrote on Wednesday, May 11, 2011:

In that case GLFW was unable to find a pixel format with multisampling.

Have you managed to get FSAA on it with any OpenGL application?

9

simcamil84 wrote on Wednesday, May 11, 2011:

I have tried with GLview using the rendering tests but it doesn’t let me
select a value for multisampling (on other computers it lets me up to 16x).
Does this mean that there is a problem with the graphic card or drivers?

Thank you

10

elmindreda wrote on Wednesday, May 11, 2011:

Most likely the driver does not expose any OpenGL pixel formats that support
FSAA. Whether this is due to a poorly written driver or limitations of the
hardware, I don’t know.

11

simcamil84 wrote on Thursday, May 12, 2011:

Ok, I will contact Matrox to see if they can fix it.

Thanks for the help.