Move QPlatformBackingStoreOpenGLSupport handling out of platform plugins

Allows them to not depend on QtOpenGL just to provide the default
backing store OpenGL support backend.

Change-Id: I90d6d9247ce76848d9d03e2d512fb736c81488d3
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

2 files changed, 12 insertions, 2 deletions

diff --git a/src/opengl/qplatformbackingstoreopenglsupport.cpp b/src/opengl/qplatformbackingstoreopenglsupport.cpp
index 511d85a400..a188d25db5 100644
--- a/src/opengl/qplatformbackingstoreopenglsupport.cpp
+++ b/src/opengl/qplatformbackingstoreopenglsupport.cpp
@@ -450,6 +450,18 @@ GLuint QPlatformBackingStoreOpenGLSupport::toTexture(const QRegion &dirtyRegion,
     return textureId;
 }
 
+static QPlatformBackingStoreOpenGLSupportBase *createOpenGLSupport()
+{
+    return new QPlatformBackingStoreOpenGLSupport;
+}
+
+static void setDefaultOpenGLSupportFactoryFunction()
+{
+    if (!QPlatformBackingStoreOpenGLSupportBase::factoryFunction())
+        QPlatformBackingStoreOpenGLSupportBase::setFactoryFunction(createOpenGLSupport);
+}
+Q_CONSTRUCTOR_FUNCTION(setDefaultOpenGLSupportFactoryFunction);
+
 #endif // QT_NO_OPENGL
 
 QT_END_NAMESPACE
diff --git a/src/opengl/qplatformbackingstoreopenglsupport.h b/src/opengl/qplatformbackingstoreopenglsupport.h
index 8868703deb..4821f7300f 100644
--- a/src/opengl/qplatformbackingstoreopenglsupport.h
+++ b/src/opengl/qplatformbackingstoreopenglsupport.h
@@ -64,14 +64,12 @@ class QOpenGLBackingStore;
 class Q_OPENGL_EXPORT QPlatformBackingStoreOpenGLSupport : public QPlatformBackingStoreOpenGLSupportBase
 {
 public:
-    explicit QPlatformBackingStoreOpenGLSupport(QPlatformBackingStore *backingStore) : backingStore(backingStore) {}
     ~QPlatformBackingStoreOpenGLSupport() override;
     void composeAndFlush(QWindow *window, const QRegion &region, const QPoint &offset,
                          QPlatformTextureList *textures, bool translucentBackground) override;
     GLuint toTexture(const QRegion &dirtyRegion, QSize *textureSize, QPlatformBackingStore::TextureFlags *flags) const override;
 
 private:
-    QPlatformBackingStore *backingStore = nullptr;
     QScopedPointer<QOpenGLContext> context;
     mutable GLuint textureId = 0;
     mutable QSize textureSize;