Added QQuickCanvas::setRenderTarget(uint fbo, const QSize &size)

This allows to hook in non-QOpenGLFrameBufferObject FBO's also

Change-Id: I8a2f8f7f15d5a92262bdbb0507b232d7c11fdf25
Reviewed-by: Jani Hautakangas <jani.hautakangas@nokia.com>

src/quick/items/qquickcanvas.cpp

@@ -264,12 +264,18 @@ void QQuickCanvasPrivate::syncSceneGraph()
 void QQuickCanvasPrivate::renderSceneGraph(const QSize &size)
 {
     Q_Q(QQuickCanvas);
+    emit q->beforeRendering();
+    int fboId = 0;
     renderer->setDeviceRect(QRect(QPoint(0, 0), size));
-    renderer->setViewportRect(QRect(QPoint(0, 0), renderTarget ? renderTarget->size() : size));
+    if (renderTargetId) {
+        fboId = renderTargetId;
+        renderer->setViewportRect(QRect(QPoint(0, 0), renderTargetSize));
+    } else {
+        renderer->setViewportRect(QRect(QPoint(0, 0), size));
+    }
     renderer->setProjectionMatrixToDeviceRect();
 
-    emit q->beforeRendering();
-    context->renderNextFrame(renderer, renderTarget);
+    context->renderNextFrame(renderer, fboId);
     emit q->afterRendering();
 }
 
@@ -285,6 +291,7 @@ QQuickCanvasPrivate::QQuickCanvasPrivate()
     , clearColor(Qt::white)
     , clearBeforeRendering(true)
     , renderTarget(0)
+    , renderTargetId(0)
     , incubationController(0)
 {
 }
@@ -1818,8 +1825,53 @@ void QQuickCanvas::setRenderTarget(QOpenGLFramebufferObject *fbo)
     }
 
     d->renderTarget = fbo;
+    if (fbo) {
+        d->renderTargetId = fbo->handle();
+        d->renderTargetSize = fbo->size();
+    } else {
+        d->renderTargetId = 0;
+        d->renderTargetSize = QSize();
+    }
+}
+
+/*!
+    \overload
+ */
+void QQuickCanvas::setRenderTarget(uint fboId, const QSize &size)
+{
+    Q_D(QQuickCanvas);
+    if (d->context && d->context && QThread::currentThread() != d->context->thread()) {
+        qWarning("QQuickCanvas::setRenderThread: Cannot set render target from outside the rendering thread");
+        return;
+    }
+
+    d->renderTargetId = fboId;
+    d->renderTargetSize = size;
+
+    // Unset any previously set instance...
+    d->renderTarget = 0;
+}
+
+
+/*!
+    Returns the FBO id of the render target when set; otherwise returns 0.
+ */
+uint QQuickCanvas::renderTargetId() const
+{
+    Q_D(const QQuickCanvas);
+    return d->renderTargetId;
 }
 
+/*!
+    Returns the size of the currently set render target; otherwise returns an enpty size.
+ */
+QSize QQuickCanvas::renderTargetSize() const
+{
+    Q_D(const QQuickCanvas);
+    return d->renderTargetSize;
+}
+
+
 
 
 /*!

src/quick/items/qquickcanvas.h

@@ -96,6 +96,10 @@ public:
     void setRenderTarget(QOpenGLFramebufferObject *fbo);
     QOpenGLFramebufferObject *renderTarget() const;
 
+    void setRenderTarget(uint fboId, const QSize &size);
+    uint renderTargetId() const;
+    QSize renderTargetSize() const;
+
     QDeclarativeIncubationController *incubationController() const;
 
     virtual QAccessibleInterface *accessibleRoot() const;

src/quick/items/qquickcanvas_p.h

@@ -182,6 +182,8 @@ public:
     uint clearBeforeRendering : 1;
 
     QOpenGLFramebufferObject *renderTarget;
+    uint renderTargetId;
+    QSize renderTargetSize;
 
     QHash<int, QQuickItem *> itemForTouchPointId;
 

src/quick/scenegraph/coreapi/qsgrenderer.cpp

@@ -93,6 +93,17 @@ void QSGBindableFbo::bind() const
     m_fbo->bind();
 }
 
+QSGBindableFboId::QSGBindableFboId(GLuint id)
+    : m_id(id)
+{
+}
+
+
+void QSGBindableFboId::bind() const
+{
+    QOpenGLContext::currentContext()->functions()->glBindFramebuffer(GL_FRAMEBUFFER, m_id);
+}
+
 /*!
     \class QSGRenderer
     \brief The renderer class is the abstract baseclass use for rendering the

src/quick/scenegraph/coreapi/qsgrenderer_p.h

@@ -199,6 +199,15 @@ private:
     QOpenGLFramebufferObject *m_fbo;
 };
 
+class QSGBindableFboId : public QSGBindable
+{
+public:
+    QSGBindableFboId(GLuint);
+    virtual void bind() const;
+private:
+    GLuint m_id;
+};
+
 
 
 QSGMaterialShader::RenderState QSGRenderer::state(QSGMaterialShader::RenderState::DirtyStates dirty) const

src/quick/scenegraph/qsgcontext.cpp

@@ -221,10 +221,10 @@ bool QSGContext::isReady() const
 }
 
 
-void QSGContext::renderNextFrame(QSGRenderer *renderer, QOpenGLFramebufferObject *fbo)
+void QSGContext::renderNextFrame(QSGRenderer *renderer, GLuint fboId)
 {
-    if (fbo) {
-        QSGBindableFbo bindable(fbo);
+    if (fboId) {
+        QSGBindableFboId bindable(fboId);
         renderer->renderScene(bindable);
     } else {
         renderer->renderScene();

src/quick/scenegraph/qsgcontext_p.h

@@ -92,7 +92,7 @@ public:
 
     QSGMaterialShader *prepareMaterial(QSGMaterial *material);
 
-    virtual void renderNextFrame(QSGRenderer *renderer, QOpenGLFramebufferObject *fbo = 0);
+    virtual void renderNextFrame(QSGRenderer *renderer, GLuint fboId);
 
     virtual QSGDistanceFieldGlyphCache *createDistanceFieldGlyphCache(const QRawFont &font);