Merge lp:~vanvugt/compiz/fix-reredirect-flicker into lp:compiz/0.9.8

[Daniel van Vugt]

Changes to the composite output window's shape seem to take a full frame to be
realized by GLX/the server. This results in a single frame of flicker when an
unredirected window gets redirected, but the shape change is still not
realized.

To work around this flicker, just skip the one frame where it's going to
occur so you never see it.
(LP: #1046664)

See commit message.

Yes, I did try XSync to force shape changes to be realized before we render but it still doesn't work. Only skipping a frame seems to work.

[jenkins (martin-mrazik+qa)]

PASSED: Continuous integration, rev:3381
http://jenkins.qa.ubuntu.com/job/compiz-ci/90/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/compiz-ci/./build=pbuilder,distribution=quantal,flavor=amd64/90/console

review: Approve (continuous-integration)

[Sam Spilsbury (smspillaz)]

This is fine, although ideally we should probably move the unredirection code into paintOutputs and not paintOutputRegion - then we can update the output window and not worry about frame skips. That's nontrivial though, so lets leave it for later.

review: Approve

=== modified file 'plugins/composite/include/composite/composite.h'
--- plugins/composite/include/composite/composite.h	2012-07-02 07:07:32 +0000
+++ plugins/composite/include/composite/composite.h	2012-09-20 09:46:21 +0000
@@ -205,6 +205,7 @@
 	void showOutputWindow ();
 	void hideOutputWindow ();
 	void updateOutputWindow ();
+	bool outputWindowChanged () const;
 
 	Window overlay ();
 	Window output ();
 
=== modified file 'plugins/composite/src/privates.h'
--- plugins/composite/src/privates.h	2012-07-02 07:07:32 +0000
+++ plugins/composite/src/privates.h	2012-09-20 09:46:21 +0000
@@ -93,6 +93,7 @@
 	CompPoint windowPaintOffset;
 
 	int overlayWindowCount;
+	bool outputShapeChanged;
 
 	struct timeval lastRedraw;
 	int            redrawTime;
 
=== modified file 'plugins/composite/src/screen.cpp'
--- plugins/composite/src/screen.cpp	2012-07-30 12:55:44 +0000
+++ plugins/composite/src/screen.cpp	2012-09-20 09:46:21 +0000
@@ -281,6 +281,7 @@
     exposeRects (),
     windowPaintOffset (0, 0),
     overlayWindowCount (0),
+    outputShapeChanged (false),
     redrawTime (1000 / FALLBACK_REFRESH_RATE),
     optimalRedrawTime (1000 / FALLBACK_REFRESH_RATE),
     scheduled (false),
@@ -543,6 +544,8 @@
 	XFixesDestroyRegion (dpy, region);
 
 	damageScreen ();
+
+	priv->outputShapeChanged = true;
     }
 }
 
@@ -591,10 +594,18 @@
 				    0, 0, region);
 
 	XFixesDestroyRegion (dpy, region);
+
+	priv->outputShapeChanged = true;
     }
 
 }
 
+bool
+CompositeScreen::outputWindowChanged () const
+{
+    return priv->outputShapeChanged;
+}
+
 void
 PrivateCompositeScreen::makeOutputWindow ()
 {
@@ -833,6 +844,8 @@
 
 	donePaint ();
 
+	priv->outputShapeChanged = false;
+
 	foreach (CompWindow *w, screen->windows ())
 	{
 	    if (w->destroyed ())
 
=== modified file 'plugins/opengl/src/screen.cpp'
--- plugins/opengl/src/screen.cpp	2012-09-13 08:35:17 +0000
+++ plugins/opengl/src/screen.cpp	2012-09-20 09:46:21 +0000
@@ -2035,6 +2035,17 @@
 	gScreen->glPaintCompositedOutput (screen->region (), scratchFbo, mask);
     }
 
+    if (cScreen->outputWindowChanged ())
+    {
+	/*
+	 * Changes to the composite output window seem to take a whole frame
+	 * to take effect. So to avoid a visible flicker, we skip this frame
+	 * and do a full redraw next time.
+	 */
+	cScreen->damageScreen ();
+	return;
+    }
+
     bool alwaysSwap = optionGetAlwaysSwapBuffers ();
     bool fullscreen = useFbo ||
                       alwaysSwap ||