Force full-screen updates for QGLWindowSurface

If the back buffer is destroyed when swap buffers is called, we must
tell the backing store any update needs to invalidate the entire
window surface, so everything gets re-drawn.

Task-number: QTBUG-9978
Reviewed-By: Trond

1 files changed, 6 insertions, 1 deletions

diff --git a/src/opengl/qwindowsurface_gl.cpp b/src/opengl/qwindowsurface_gl.cpp
index b693245..bcb96fa 100644
--- a/src/opengl/qwindowsurface_gl.cpp
+++ b/src/opengl/qwindowsurface_gl.cpp
@@ -82,7 +82,7 @@
 #define GLX_SAMPLES_ARB         100001
 #endif
 
-#ifdef QT_OPENGL_ES
+#ifndef QT_NO_EGL
 #include <private/qeglcontext_p.h>
 #endif
 
@@ -354,6 +354,11 @@ void QGLWindowSurface::hijackWindow(QWidget *widget)
     QGLContext *ctx = new QGLContext(surfaceFormat, widget);
     ctx->create(qt_gl_share_widget()->context());
 
+#ifndef QT_NO_EGL
+    if (ctx->d_func()->eglContext->configAttrib(EGL_SWAP_BEHAVIOR) != EGL_BUFFER_PRESERVED)
+        setPartialUpdateSupport(false); // Force full-screen updates
+#endif
+
     widgetPrivate->extraData()->glContext = ctx;
 
     union { QGLContext **ctxPtr; void **voidPtr; };