Fixed rendering errors in blurpicker with -graphicssystem opengl

1) Need to transfer to brush drawing mode when switching active engine,
to make sure we reset the vertex / texture coordinate pointers for image
drawing.

2) QGLPixmapGLPaintDevice::beginPaint() was changed to use
QGLContext::drawTexture() for blitting the old texture contents to the
render FBO, which means that we also need to set up viewport, modelview,
and projection matrices, and ensure that clipping / stencil testing
is disabled.

3) Make sure stencil testing is disabled when clearing the FBO.

Reviewed-by: Tom

2 files changed, 16 insertions, 1 deletions

diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index 5e790cf..e41d0b4 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -1385,6 +1385,7 @@ void QGL2PaintEngineEx::ensureActive()
     d->device->ensureActiveTarget();
 
     if (d->needsSync) {
+        d->transferMode(BrushDrawingMode);
         glViewport(0, 0, d->width, d->height);
         glDepthMask(false);
         glDepthFunc(GL_LESS);
diff --git a/src/opengl/qpixmapdata_gl.cpp b/src/opengl/qpixmapdata_gl.cpp
index 0bc46e1..d5398a9 100644
--- a/src/opengl/qpixmapdata_gl.cpp
+++ b/src/opengl/qpixmapdata_gl.cpp
@@ -149,6 +149,7 @@ void QGLPixmapGLPaintDevice::beginPaint()
     if (data->needsFill()) {
         const QColor &c = data->fillColor();
         float alpha = c.alphaF();
+        glDisable(GL_SCISSOR_TEST);
         glClearColor(c.redF() * alpha, c.greenF() * alpha, c.blueF() * alpha, alpha);
         glClear(GL_COLOR_BUFFER_BIT);
     }
@@ -157,8 +158,21 @@ void QGLPixmapGLPaintDevice::beginPaint()
         // uploaded from an image or rendered into before), we need to
         // copy it from the texture to the render FBO.
 
+        glDisable(GL_DEPTH_TEST);
+        glDisable(GL_SCISSOR_TEST);
+        glDisable(GL_BLEND);
+
+        glMatrixMode(GL_MODELVIEW_MATRIX);
+        glLoadIdentity();
+
+        glMatrixMode(GL_PROJECTION_MATRIX);
+        glLoadIdentity();
+        glOrtho(0, data->width(), data->height(), 0, -999999, 999999);
+
+        glViewport(0, 0, data->width(), data->height());
+
         // Pass false to bind so it doesn't copy the FBO into the texture!
-        context()->drawTexture(QPointF(0.0, 0.0), data->bind(false));
+        context()->drawTexture(QRect(0, 0, data->width(), data->height()), data->bind(false));
     }
 }