Mesa (master): wgl: Fix visual's buffer_mask configuration.

[Jose Fonseca]

Module: Mesa
Branch: master
Commit: 63df5a464e984af771b3896d05baa258912ac202
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=63df5a464e984af771b3896d05baa258912ac202

Author: José Fonseca <jfonseca at vmware.com>
Date:   Thu Dec  2 20:21:39 2010 +0000

wgl: Fix visual's buffer_mask configuration.

---

 src/gallium/state_trackers/wgl/stw_pixelformat.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/gallium/state_trackers/wgl/stw_pixelformat.c b/src/gallium/state_trackers/wgl/stw_pixelformat.c
index 18ac482..5ede1d4 100644
--- a/src/gallium/state_trackers/wgl/stw_pixelformat.c
+++ b/src/gallium/state_trackers/wgl/stw_pixelformat.c
@@ -185,7 +185,7 @@ stw_pixelformat_add(
     */
    pfi->stvis.buffer_mask = ST_ATTACHMENT_FRONT_LEFT_MASK;
    if (doublebuffer)
-      pfi->stvis.buffer_mask = ST_ATTACHMENT_BACK_LEFT_MASK;
+      pfi->stvis.buffer_mask |= ST_ATTACHMENT_BACK_LEFT_MASK;
 
    pfi->stvis.color_format = color->format;
    pfi->stvis.depth_stencil_format = depth->format;