swr: Enable MSAA in OpenSWR software renderer

This patch enables multisample antialiasing in the OpenSWR software renderer.

MSAA is a proof-of-concept/work-in-progress with bug fixes and performance
on the way.  We wanted to get the changes out now to allow several customers
to begin experimenting with MSAA in a software renderer.  So as not to
impact current customers, MSAA is turned off by default - previous
functionality and performance remain intact.  It is easily enabled via
environment variables, as described below.

It has only been tested with the glx-lib winsys.  The intention is to
enable other state-trackers, both Windows and Linux and more fully support
FBOs.

There are 2 environment variables that affect behavior:

* SWR_MSAA_FORCE_ENABLE - force MSAA on, for apps that are not designed
  for MSAA... Beware, results will vary.  This is mainly for testing.

* SWR_MSAA_MAX_SAMPLE_COUNT - sets maximum supported number of
  samples (1,2,4,8,16), or 0 to disable MSAA altogether.
  (The default is currently 0.)

Reviewed-by: George Kyriazis <[email protected]>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/gallium/drivers/swr/swr_screen.h b/src/gallium/drivers/swr/swr_screen.h
index 0c82a2eff7a..dc1bb47f02d 100644
--- a/src/gallium/drivers/swr/swr_screen.h
+++ b/src/gallium/drivers/swr/swr_screen.h
@@ -24,10 +24,15 @@
 #ifndef SWR_SCREEN_H
 #define SWR_SCREEN_H
 
+#include "swr_resource.h"
+
 #include "pipe/p_screen.h"
 #include "pipe/p_defines.h"
+#include "util/u_format.h"
 #include "api.h"
 
+#include "memory/TilingFunctions.h"
+
 struct sw_winsys;
 
 struct swr_screen {
@@ -38,6 +43,9 @@ struct swr_screen {
 
    struct sw_winsys *winsys;
 
+   boolean msaa_force_enable;
+   uint8_t msaa_max_count;
+
    HANDLE hJitMgr;
 };