   Load zbuffer with own data
  I need to load zbuffer with my own depth data taken from Maya. I´ve made it work using glDrawPixels(). However this instruction is very slow. Is there a faster way to do it?. Thanks in advance.   
  Once EXT_framebuffer_object support appears in drivers (give it a few months) you can probably render right to the depth buffer. But I don't know of any current way to pull it off.   ;  Can't you do a normal render with color write disabled?   ;  You could probably do this using GLSL,if you store your depth values in a texture and draw a full screen quad, textured with this and output the texture value ( which is the depth ) to gl_FragDepth from your fragment shader.