Implement GLX_SGI_make_current_read

Discontinue use of the old GetBuffeSize interface.  Track both the
current read-drawable and the current draw-drawable.  After moving
some context state to via_rednerbuffer, GLX_SGI_make_current_read can
be enabled.

The extension works, but the wincopy test prodcues a black window for
the destination window.  After messing around with the window and
looking at the code, I believe the problem is in the handling of
buffer swap requests on a drawable that isn't the current draw-drawable.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/mesa/drivers/dri/unichrome/via_screen.c b/src/mesa/drivers/dri/unichrome/via_screen.c
index 98a742c720..28e1f9451e 100644
--- a/src/mesa/drivers/dri/unichrome/via_screen.c
+++ b/src/mesa/drivers/dri/unichrome/via_screen.c
@@ -182,6 +182,7 @@ viaInitDriver(__DRIscreenPrivate *sPriv)
 	  (*glx_enable_extension)( psc, "GLX_MESA_swap_control" );
        }
 
+       (*glx_enable_extension)( psc, "GLX_SGI_make_current_read" );
        (*glx_enable_extension)( psc, "GLX_MESA_swap_frame_usage" );
     }