Drawing FBO with OpenGL on computer hungs

Question

I have two computers, a Toshiba laptop with an i5 and ATI Radeon HD 5145, and an old Dell desktop, with Pentium D and ATI Radeon X1300 Series.

I have created a Java application, using LWJGL, that creates an FBO. The texture attached to the FBO is the size of the screen (1366x768 on the Toshiba and 1024x768 on the Dell).

I try the same application on both computers, using a program called MSI Afterburner to see the CPU usage, GPU usage and framerate.

On the Toshiba, it works perfect, on the Dell it hungs. I explain better later on.

Below is the code for creating the FBO:

//Create FBO
DisplayMode display = Display.getDisplayMode();

int fboWidth  = display.getWidth();
int fboHeight = display.getHeight();

int fboTextureID = glGenTextures();
int fboID = glGenFramebuffersEXT(); 

glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, fboID);

glBindTexture(GL_TEXTURE_2D, fboTextureID);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); 
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); 
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, fboWidth, fboHeight, 0, GL_RGBA, GL_INT, 
(java.nio.IntBuffer) null);

glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
GL_TEXTURE_2D, fboTextureID, 0);

glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
glBindTexture(GL_TEXTURE_2D, 0);

This is the while loop where the FBO is displayed:

while(true)
{
    renderFBO();

    glClearColor(1.0f, 1.0f, 1.0f, 0.0f);
    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, fboTextureID);
    glBegin(GL_QUADS);

    glColor4f(1.0f, 1.0f, 1.0f, 1.0f);

    int x=0; int y=0; //FBO position
    int w=fboWidth; int h=fboHeight; //FBO size

    glTexCoord2f(0, 1);
    glVertex2f(x, y); 
    glTexCoord2f(1, 1);
    glVertex2f(x+w, y);
    glTexCoord2f(1, 0);
    glVertex2f(x+w, y+h);
    glTexCoord2f(0, 0);
    glVertex2f(x, y+h);

    glEnd();
    glBindTexture(GL_TEXTURE_2D, 0);

    glDisable(GL_TEXTURE_2D);
    Display.update(); //Update the screen
    Display.sync(60); //Cap the framerate to 60fps
}

This method draws some textures to the FBO offscreen

private void renderFBO()
    {
        glClearColor(1.0f, 1.0f, 1.0f, 0.0f);

        //Start FBO drawing
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fboID );
        glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
        glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        //Here I draw some textures using quads

        //Stop FBO drawing
        glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0);
        glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    }

As I said before, the application on the Toshiba with the Radeon HD works perfect. 5% CPU usage, 20% GPU usage and 60fps.

When executing this application on the old Dell with the Radeon X1300 the computer hungs; the CPU usage is 50%, the GPU can't be measured and the fps is 0.

If I don't draw the FBO, just render it offscreen, then the old Dell doesn't hung, and I get normal results 5% CPU usage, 20% GPU usage and 60fps.

It's drawing the FBO in the quad what causes the computer to hung. And I ask, why? Why does this happen? Is there something wrong with my code? At first I thought it was the computer just being too old (it's from 2006) and having trouble dealing with FBO's, but then why doesn't it hung when rendering the FBO offscreen?

Answer 1

PROBLEM SOLVED

Finally got it working on the old Dell. I had to use a power of 2 texture. The ATI HD can handle non-power of 2 textures apparently, so I can attach a 1366x768 texture size to the FBO. However, I can't attach a 1024x768 texture with the ATI X1300. Using a 1024x1024 texture I get the application working at 60fps and little cpu usage.

Answer 2

Maybe it's an issue with the video card not supporting OpenGL, or at least the features you're using.