Add swapbuffers and vsync_wait optionsHEADmaster

Some drivers will automatically prevent tearing when swapbuffers or
copysubbuffer is called, and will throttle drawing at that time as well
(usually to the refresh rate); the --no-wait option can be used in that
case.

And for testing drivers, the --always-swap option can be nice, since it
will force full screen updates, allowing page flipping paths to be
taken, for example.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

2 files changed, 20 insertions, 3 deletions

diff --git a/src/display.c b/src/display.c
index caf63d46..dcb05cb9 100644
--- a/src/display.c
+++ b/src/display.c
@@ -1450,6 +1450,9 @@ eventLoop (void)
 						      s->idle ? s->redrawTime :
 						      timeDiff);
 
+			if (alwaysSwap == TRUE)
+			    damageScreen (s);
+
 			/* substract top most overlay window region */
 			if (s->overlayWindowCount)
 			{
@@ -1509,9 +1512,11 @@ eventLoop (void)
 			targetScreen = NULL;
 			targetOutput = &s->outputDev[0];
 
-			waitForVideoSync (s);
+			if (!noWait)
+			    waitForVideoSync (s);
 
-			if (mask & COMP_SCREEN_DAMAGE_ALL_MASK)
+			if ((mask & COMP_SCREEN_DAMAGE_ALL_MASK) ||
+			    (alwaysSwap == TRUE))
 			{
 			    glXSwapBuffers (d->display, s->output);
 			}
diff --git a/src/main.c b/src/main.c
index e089bbb0..8f20a1c0 100644
--- a/src/main.c
+++ b/src/main.c
@@ -63,6 +63,8 @@ Bool strictBinding = TRUE;
 Bool noDetection = FALSE;
 Bool useDesktopHints = FALSE;
 Bool onlyCurrentScreen = FALSE;
+Bool noWait = FALSE;
+Bool alwaysSwap = FALSE;
 
 #ifdef USE_COW
 Bool useCow = TRUE;
@@ -85,7 +87,9 @@ usage (void)
 	    "[--replace]\n       "
 	    "[--sm-disable] "
 	    "[--sm-client-id ID] "
-	    "[--only-current-screen]\n      "
+	    "[--only-current-screen] "
+ 	    "[--no-wait]\n       "
+ 	    "[--always-swap]"
 
 #ifdef USE_COW
 	    " [--use-root-window] "
@@ -364,6 +368,14 @@ main (int argc, char **argv)
 	    if (i + 1 < argc)
 		backgroundImage = argv[++i];
 	}
+	else if (!strcmp (argv[i], "--no-wait"))
+	{
+	    noWait = TRUE;
+	}
+	else if (!strcmp (argv[i], "--always-swap"))
+	{
+	    alwaysSwap = TRUE;
+	}
 	else if (*argv[i] == '-')
 	{
 	    compLogMessage ("core", CompLogLevelWarn,