Re-order begin() so everything needing a current context has one

It should be up to QGLPaintDevice::beginPaint() to make the correct
context current, so everything needing a current context needs to be
moved after that call.

This patch also modifies QGLPixmapData to use QGLContext::drawTexture
rather than the GL2 PE's drawTexture, which shouldn't be called inside
beginPaint as the paint engine hasn't been fully initialised yet.

Reviewed-by: Eskil

2 files changed, 14 insertions, 18 deletions

diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index 2eacef0..4427ee9 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -1318,23 +1318,13 @@ bool QGL2PaintEngineEx::begin(QPaintDevice *pdev)
         return false;
 
     d->ctx = d->device->context();
-
     d->ctx->d_ptr->active_engine = this;
-    d->last_created_state = 0;
 
-    QSize sz = d->device->size();
+    const QSize sz = d->device->size();
     d->width = sz.width();
     d->height = sz.height();
+    d->last_created_state = 0;
     d->mode = BrushDrawingMode;
-
-#if !defined(QT_OPENGL_ES_2)
-    d->ctx->makeCurrent();
-    bool success = qt_resolve_version_2_0_functions(d->ctx);
-    Q_ASSERT(success);
-#endif
-
-    d->shaderManager = new QGLEngineShaderManager(d->ctx);
-
     d->brushTextureDirty = true;
     d->brushUniformsDirty = true;
     d->matrixDirty = true;
@@ -1346,8 +1336,18 @@ bool QGL2PaintEngineEx::begin(QPaintDevice *pdev)
     d->needsSync = true;
     d->use_system_clip = !systemClip().isEmpty();
 
+    // 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();
 
+#if !defined(QT_OPENGL_ES_2)
+    bool success = qt_resolve_version_2_0_functions(d->ctx);
+    Q_ASSERT(success);
+#endif
+
+    d->shaderManager = new QGLEngineShaderManager(d->ctx);
+
     if (!d->inRenderText) {
         glDisable(GL_DEPTH_TEST);
         glDisable(GL_SCISSOR_TEST);
diff --git a/src/opengl/qpixmapdata_gl.cpp b/src/opengl/qpixmapdata_gl.cpp
index fa1b815..0bc46e1 100644
--- a/src/opengl/qpixmapdata_gl.cpp
+++ b/src/opengl/qpixmapdata_gl.cpp
@@ -157,12 +157,8 @@ void QGLPixmapGLPaintDevice::beginPaint()
         // uploaded from an image or rendered into before), we need to
         // copy it from the texture to the render FBO.
 
-        // Pass false to tell bind to _not_ copy the FBO into the texture!
-        GLuint texId = data->bind(false);
-
-        QGL2PaintEngineEx* pe = static_cast<QGL2PaintEngineEx*>(data->paintEngine());
-        QRect rect(0, 0, data->width(), data->height());
-        pe->drawTexture(QRectF(rect), texId, rect.size(), QRectF(rect));
+        // Pass false to bind so it doesn't copy the FBO into the texture!
+        context()->drawTexture(QPointF(0.0, 0.0), data->bind(false));
     }
 }