Yes, that is exactly right, that one line is what specifically attaches a depth buffer to a framebuffer object. Framebuffer objects are fully customisable, you don’t need to have depth, colour or stencil buffers, you can do a combination of buffers to get exactly what you want. There are times when a colour buffer isn’t required, but a depth buffer is, and it saves a lot of processing.

Cheers,
Swiftless

Btw, i have a question, where does the fbo_depth variable obtain the depth buffer data?

or does this line

glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, fbo_depth);

actually do the magic for assigning the depth buffer to fbo_depth?

#define haltitude(expr) breakitude(expr)
//#define haltitude(expr) assert(expr)
#define breakitude(expr) {if(expr){}else{_asm int 3}}

void assertSameSize(unsigned int t[8])
{
int firstWidth = 0;
int firstHeight = 0;
int width;
int height;

for(int i=0; i<8; ++i)
{
if(t[i] && glIsTexture(t[i]))
{
glBindTexture(GL_TEXTURE_2D, t[i]);
glGetTexLevelParameteriv(GL_TEXTURE_2D,0,GL_TEXTURE_WIDTH,&width);
glGetTexLevelParameteriv(GL_TEXTURE_2D,0,GL_TEXTURE_HEIGHT,&height);
glBindTexture(GL_TEXTURE_2D,0);

if(0==i)
{
firstWidth = width;
firstHeight = height;
continue;
}

haltitude(width==firstWidth);
haltitude(height==firstHeight);
}
}
}

thank you for your perseverance Swiftfless!