Added workarounds for two MBX/SGX specific GL ES bugs/problems.

The workaround flags are put into the platform independent section
for now, since there might be a general need for these as we expand
our GL and GL ES usage. The workaround_needsFullClearOnEveryFrame flag
covers the case where you get a performance penalty on PowerVR hw
if all rendering buffers are not cleared. The
workaround_brokenFBOReadBack flag covers the case where copying pixels
from a texture (e.g. via glCopyTexSubImage2d()) bound in an FBO doesn't
work.

Task-number: QTBUG-10670
Reviewed-by: Gunnar

1 files changed, 4 insertions, 1 deletions

diff --git a/src/opengl/qglpaintdevice.cpp b/src/opengl/qglpaintdevice.cpp
index e874e85c38..e1dcbfde89 100644
--- a/src/opengl/qglpaintdevice.cpp
+++ b/src/opengl/qglpaintdevice.cpp
@@ -175,7 +175,10 @@ void QGLWidgetGLPaintDevice::beginPaint()
             float alpha = c.alphaF();
             glClearColor(c.redF() * alpha, c.greenF() * alpha, c.blueF() * alpha, alpha);
         }
-        glClear(GL_COLOR_BUFFER_BIT);
+        if (context()->d_func()->workaround_needsFullClearOnEveryFrame)
+            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+        else
+            glClear(GL_COLOR_BUFFER_BIT);
     }
 }