diff --git a/panda/src/glgsg/glGraphicsStateGuardian.cxx b/panda/src/glgsg/glGraphicsStateGuardian.cxx
index b27ef4e7a3..ce9810bbd4 100644
--- a/panda/src/glgsg/glGraphicsStateGuardian.cxx
+++ b/panda/src/glgsg/glGraphicsStateGuardian.cxx
@@ -1983,9 +1983,9 @@ copy_pixel_buffer(PixelBuffer *pb, const DisplayRegion *dr) {
     << (void *)pb->_image.p() << ")" << endl;
 #endif
 
-
-//glReadPixels( pb->get_xorg() + xo, pb->get_yorg() + yo,  // pb->origin is probably a meaningless vestigial field thats always zero.  shouldnt be added here
-  glReadPixels(xo, yo, 
+  // pixelbuffer "origin" represents upper left screen point at which
+  // pixelbuffer should be drawn using draw_pixel_buffer
+  glReadPixels(pb->get_xorg() + xo, pb->get_yorg() + yo,  
 			   pb->get_xsize(), pb->get_ysize(), 
 			   get_external_image_format(pb->get_format()),
 			   get_image_type(pb->get_image_type()),