Multisample quality for screen not as good as for FBO on ATI Radeon

[CRasterImage]

I am not sure if this is a card-specific thing, driver-specific or if I am doing something wrong.

Here is the problem:
The card (ATI Radeon HD 4300/4500 Series) does 4x multisampling. The quality of the output is lower when drawing to the screen
http://chattypics.com/files/screen_q1oju76nc2.png
than it is if you draw to a multisampled FBO
http://chattypics.com/files/fbo_e4amht2pnv.png


The problem doesn't appear on my other machine which has an NVidia card.
But then, that card does 16x multisampling and maybe the difference there. But just isn't noticeable.

[Alfonse Reinheart]

How are you doing your "multisampled FBO"?

[CRasterImage]

      glGenFramebuffersEXT( 1, &m_DL_FBO );
      glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_DL_FBO);
 
      //Now make a multisample color buffer
      int samples = CDLOpenGLCaps::Instance()->Cap_int(DLOCT_MULTISAMPLE_SAMPLES);
 
      glGenRenderbuffersEXT(1, &m_DL_FBO_color_buffer);
      glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, m_DL_FBO_color_buffer);
      glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, samples, GL_RGBA8, m_FBO_width, m_FBO_height);
 
      //----------------------
      //Make a stencil buffer
      //This is a combo depth+stencil buffer
      //because it is the most widely supported way of doing things.
      //even when you don't need, or use, the depth buffer.
      glGenRenderbuffersEXT(1, &m_DL_FBO_stencil_buffer);
      glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, m_DL_FBO_stencil_buffer);
      glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, samples, GL_DEPTH24_STENCIL8_EXT, m_FBO_width, m_FBO_height);
 
 
      //It's time to attach the RBs to the FBO
      glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_RENDERBUFFER_EXT, m_DL_FBO_color_buffer);
      glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, m_DL_FBO_stencil_buffer);
      glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, m_DL_FBO_stencil_buffer);
      //Make sure FBO status is good
      CheckForFBOError();
      glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);