Index: trunk/src/gl/gl_context.cc
===================================================================
--- trunk/src/gl/gl_context.cc	(revision 520)
+++ trunk/src/gl/gl_context.cc	(revision 523)
@@ -212,4 +212,22 @@
 
 }
+
+void nv::gl_context::attach_depth( framebuffer source, framebuffer target )
+{
+	gl_framebuffer_info* sinfo = m_framebuffers.get( source );
+	gl_framebuffer_info* tinfo = m_framebuffers.get( target );
+
+	if ( sinfo && tinfo )
+	{
+		glBindFramebuffer( GL_FRAMEBUFFER, tinfo->glid );
+		// TODO: do we need to bind the renderbuffer at all?
+		glBindRenderbuffer( GL_RENDERBUFFER, sinfo->depth_rb_glid );
+		glFramebufferRenderbuffer( GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, sinfo->depth_rb_glid );
+		glBindRenderbuffer( GL_RENDERBUFFER, 0 );
+		glBindRenderbuffer( GL_FRAMEBUFFER, 0 );
+	}
+
+}
+
 
 void nv::gl_context::blit( framebuffer f, buffer_mask mask, ivec2 src1, ivec2 src2, ivec2 dst1, ivec2 dst2 )