what's wrong with this?

OpenGL OpenGL: Advanced Coding
1

My opengl program runs only 7 FPS on Radeon 8500. I have trimmed the code so that it only draws a cube with no texturing, no buffer clear, no vertex buffer.

This program can reach over 200 FPS on TNT2, Geforce, G450, etc, with the only exception of 7 FPS on Radeon 8500. I am sure I have installed the latest driver.

This program calls ogl functions in MFC’s CChildView::OnPaint().

Other glut programs run well.

Can anyone tell me what may cause the problem?

2
  1. Have you got the latest ATI drivers for your radeon?
  2. Perhaps some form of memory leak?
  3. Perhaps something with the stencil buffer or a non HW accelerated feature on the Radeon (SW Pixelformat)?

I guess it would be the best to give us a short look into your source .

Diapolo

3

Perhaps you request pixelformatdescriptor which is not available for hardware rendering on the Radeon.

4

Well, here is the pixel format init code…

BOOL CGLWindow::InitPixel(HDC hdc)
{
PIXELFORMATDESCRIPTOR pfd = {
sizeof(PIXELFORMATDESCRIPTOR), // size of this pfd
1, // version number
PFD_DRAW_TO_WINDOW | // support window
PFD_SUPPORT_OPENGL | // support OpenGL
PFD_DOUBLEBUFFER ,

  	PFD_TYPE_RGBA,             // RGBA type 
  	16,                        // 24-bit color depth 
  	0, 0, 0, 0, 0, 0,          // color bits ignored 
  	0,                         // no alpha buffer 
  	0,                         // shift bit ignored 
  	0,                         // no accumulation buffer 
  	0, 0, 0, 0,                // accum bits ignored 
  	32,                        // 32-bit z-buffer	 
  	0,                         // no stencil buffer 
  	0,                         // no auxiliary buffer 
  	PFD_MAIN_PLANE,            // main layer 
  	0,                         // reserved 
  	0, 0, 0                    // layer masks ignored

};
int iPixelFormat = ChoosePixelFormat(hdc, &pfd );
BOOL bResault = SetPixelFormat(hdc, iPixelFormat , &pfd );
m_hGlRC = wglCreateContext( hdc );
wglMakeCurrent( hdc, m_hGlRC );
glDepthFunc( GL_LEQUAL );
return TRUE;
}

5 
[b]
			16,                        // 24-bit color depth 
...
			32,                        // 32-bit z-buffer

[/b]

Don’t know the Radeon (I’m on GF2), but 16 bit color combined with 32 bit depth may be the prob.

HTH

Jean-Marc

[This message has been edited by JML (edited 03-13-2002).]

6

Try this, if the if-key is true, then you only have got SW mode.

int iPFDFormat = pfd.dwFlags & PFD_GENERIC_FORMAT;
int iPFDAccelerated = pfd.dwFlags & PFD_GENERIC_ACCELERATED;
if(iPFDFormat && ! iPFDAccelerated)
{
// SW mode
}

Diapolo