FBO failure

OpenGL OpenGL: Advanced Coding
1

I’m using FBO’s for rendering to textures. In this case there is no z buffering, just a simple color buffer.

On nvidia cards this seems to work fine under both Linux and Windows. Also on the ATI X1600 on a MacBook pro it also works fine. But on older ATI hardware (9600 XT) on Windows this fails with the enum FRAMEBUFFER_INCOMPLETE_ATTACHMENT from glCheckFramebufferStatusEXT()

This is the relevant code:

(target_ is GL_TEXTURE_2D, width_ is 256, height_ is 128 and z_depth_ is 0)

 
bool FBOTexture::initBuffers()
{
 bool result = true;
 // create objects
 glGenFramebuffersEXT(1, &fb_);        // Frame buffer object
 glGenTextures(1, &handle_);           // Texture handle
 if(z_depth_ > 0)
    glGenRenderbuffersEXT(1, &depth_rb_); // Render buffer for z buffering
 
 // Make frame buffer active
 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb_);
 
 // Initialize texture
 glBindTexture(target_, handle_);
 applyTexParameters(target_);

 GLenum int_fmt, data_type, data_fmt;
 GngImage::Format new_fmt = getGLFormat(pixel_fmt_, int_fmt, data_fmt, data_type);
 if(new_fmt != pixel_fmt_)
    {
    pixel_fmt_ = new_fmt;
    getGLFormat(pixel_fmt_, int_fmt, data_fmt, data_type);
    }
 glTexImage2D(target_, 0, GL_RGBA8, width_, height_, 0, data_fmt, data_type, (GLvoid*)NULL);

 // Establish a mipmap chain
 if(min_filter_ != GL_NEAREST &&
    min_filter_ != GL_LINEAR)
    glGenerateMipmapEXT(target_);
 
 // Attach texture to framebuffer color buffer
 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, target_, handle_, 0);

 // Initialize depth renderbuffer
 if(z_depth_ > 0)
    {
    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, depth_rb_);
    GLenum depth_fmt = GL_DEPTH_COMPONENT;
    if(z_depth_ == 16)
       depth_fmt = GL_DEPTH_COMPONENT16;
    else if(z_depth_ == 24)
       depth_fmt = GL_DEPTH_COMPONENT24;
    else if(z_depth_ == 32)
       depth_fmt = GL_DEPTH_COMPONENT32;
    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, depth_fmt, width_, height_);
    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, depth_rb_);
    }
 
 // Check framebuffer status
 GLuint status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
 if(status != GL_FRAMEBUFFER_COMPLETE_EXT)
    {
    logError() << "GngFBOTexture: initBuffers() failed, FBO not complete!: " << endl;
    result = false;
    switch(status)
       {
       case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT:
          logError() << "Reason: FRAMEBUFFER_INCOMPLETE_ATTACHMENT" << endl;
          break;

... more cases...

       }
    }
 
 // Set rendering to window
 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

 return result;
}

If anyone has any ideas, I’d be overjoyed :slight_smile:

Cheers!