Improved and made public the QOpenGLPaintDevice API.

The new API is more flexible, allowing the use of QOpenGLPaintDevice
with any QOpenGLContext, and putting more responsibility on the user for
ensuring the correct FBO is current (the user knows best anyhow).

Task-number: QTBUG-21263

Change-Id: I50b954125f552baef52fbb3fe2ed907a11ad519c
Reviewed-on: http://codereview.qt-project.org/4325
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Paul Olav Tvete <paul.tvete@nokia.com>

1 files changed, 13 insertions, 22 deletions

diff --git a/src/gui/opengl/qopenglpaintengine.cpp b/src/gui/opengl/qopenglpaintengine.cpp
index dfb8549375..519dd3b893 100644
--- a/src/gui/opengl/qopenglpaintengine.cpp
+++ b/src/gui/opengl/qopenglpaintengine.cpp
@@ -342,7 +342,7 @@ void QOpenGL2PaintEngineExPrivate::updateBrushUniforms()
         QTransform translate(1, 0, 0, 1, -translationPoint.x(), -translationPoint.y());
         qreal m22 = -1;
         qreal dy = height;
-        if (device->isFlipped()) {
+        if (device->paintFlipped()) {
             m22 = 1;
             dy = 0;
         }
@@ -390,7 +390,7 @@ void QOpenGL2PaintEngineExPrivate::updateMatrix()
     GLfloat dx = transform.dx();
     GLfloat dy = transform.dy();
 
-    if (device->isFlipped()) {
+    if (device->paintFlipped()) {
         hfactor *= -1;
         dy -= height;
     }
@@ -542,7 +542,8 @@ void QOpenGL2PaintEngineEx::beginNativePainting()
         d->funcs.glDisableVertexAttribArray(i);
 
 #ifndef QT_OPENGL_ES_2
-    const QSurfaceFormat &fmt = d->device->format();
+    Q_ASSERT(QOpenGLContext::currentContext());
+    const QSurfaceFormat &fmt = d->device->context()->format();
     if (fmt.majorVersion() < 3 || (fmt.majorVersion() == 3 && fmt.minorVersion() < 1)
         || fmt.profile() == QSurfaceFormat::CompatibilityProfile)
     {
@@ -878,7 +879,7 @@ void QOpenGL2PaintEngineExPrivate::fill(const QVectorPath& path)
             // Tag it for later so that if the same path is drawn twice, it is assumed to be static and thus cachable
             path.makeCacheable();
 
-            if (!device->format().stencilBufferSize()) {
+            if (device->context()->format().stencilBufferSize() == 0) {
                 // If there is no stencil buffer, triangulate the path instead.
 
                 QRectF bbox = path.controlPointRect();
@@ -1421,7 +1422,7 @@ void QOpenGL2PaintEngineEx::drawStaticTextItem(QStaticTextItem *textItem)
                                                 ? QFontEngineGlyphCache::Type(textItem->fontEngine()->glyphFormat)
                                                 : d->glyphCacheType;
         if (glyphType == QFontEngineGlyphCache::Raster_RGBMask) {
-            if (d->device->alphaRequested() || s->matrix.type() > QTransform::TxTranslate
+            if (d->device->context()->format().alphaBufferSize() > 0 || s->matrix.type() > QTransform::TxTranslate
                 || (s->composition_mode != QPainter::CompositionMode_Source
                 && s->composition_mode != QPainter::CompositionMode_SourceOver))
             {
@@ -1480,7 +1481,7 @@ void QOpenGL2PaintEngineEx::drawTextItem(const QPointF &p, const QTextItem &text
 
 
     if (glyphType == QFontEngineGlyphCache::Raster_RGBMask) {
-        if (d->device->alphaRequested() || txtype > QTransform::TxTranslate
+        if (d->device->context()->format().alphaBufferSize() > 0 || txtype > QTransform::TxTranslate
             || (state()->composition_mode != QPainter::CompositionMode_Source
             && state()->composition_mode != QPainter::CompositionMode_SourceOver))
         {
@@ -1944,17 +1945,14 @@ bool QOpenGL2PaintEngineEx::begin(QPaintDevice *pdev)
 {
     Q_D(QOpenGL2PaintEngineEx);
 
-//     qDebug("QOpenGL2PaintEngineEx::begin()");
-    if (pdev->devType() == QInternal::OpenGL)
-        d->device = static_cast<QOpenGLPaintDevice*>(pdev);
-    else
-        d->device = QOpenGLPaintDevice::getDevice(pdev);
+    Q_ASSERT(pdev->devType() == QInternal::OpenGL);
+    d->device = static_cast<QOpenGLPaintDevice*>(pdev);
 
     if (!d->device)
         return false;
 
-    if (d->device->group() != QOpenGLContextGroup::currentContextGroup()) {
-        qWarning("QPainter::begin(): OpenGL resource not valid in current context");
+    if (d->device->context() != QOpenGLContext::currentContext()) {
+        qWarning("QPainter::begin(): QOpenGLPaintDevice's context needs to be current");
         return false;
     }
 
@@ -1983,10 +1981,6 @@ bool QOpenGL2PaintEngineEx::begin(QPaintDevice *pdev)
     d->dirtyStencilRegion = QRect(0, 0, d->width, d->height);
     d->stencilClean = true;
 
-    // Calling begin paint should make the correct context current. So, any
-    // code which calls into GL or otherwise needs a current context *must*
-    // go after beginPaint:
-    d->device->beginPaint();
     d->shaderManager = new QOpenGLEngineShaderManager(d->ctx);
 
     glDisable(GL_STENCIL_TEST);
@@ -2013,7 +2007,7 @@ bool QOpenGL2PaintEngineEx::begin(QPaintDevice *pdev)
 #if defined(QT_OPENGL_ES_2)
     // OpenGL ES can't switch MSAA off, so if the gl paint device is
     // multisampled, it's always multisampled.
-    d->multisamplingAlwaysEnabled = d->device->format().samples() > 1;
+    d->multisamplingAlwaysEnabled = d->device->context()->format().samples() > 1;
 #else
     d->multisamplingAlwaysEnabled = false;
 #endif
@@ -2028,7 +2022,6 @@ bool QOpenGL2PaintEngineEx::end()
     QOpenGLContext *ctx = d->ctx;
     d->funcs.glUseProgram(0);
     d->transferMode(BrushDrawingMode);
-    d->device->endPaint();
 
     ctx->d_func()->active_engine = 0;
 
@@ -2062,8 +2055,6 @@ void QOpenGL2PaintEngineEx::ensureActive()
         d->needsSync = true;
     }
 
-    d->device->ensureActiveTarget();
-
     if (d->needsSync) {
         d->transferMode(BrushDrawingMode);
         glViewport(0, 0, d->width, d->height);
@@ -2120,7 +2111,7 @@ void QOpenGL2PaintEngineExPrivate::setScissor(const QRect &rect)
     const int left = rect.left();
     const int width = rect.width();
     int bottom = height - (rect.top() + rect.height());
-    if (device->isFlipped()) {
+    if (device->paintFlipped()) {
         bottom = rect.top();
     }
     const int height = rect.height();