Fixed having a QPainter active on several FBOs at the same time.

It's insufficient to use a single paint engine to render to all FBOs. If
the default engine is already in used we need to create our own engine.

Reviewed-by: Trond

1 files changed, 29 insertions, 10 deletions

diff --git a/src/opengl/qglframebufferobject.cpp b/src/opengl/qglframebufferobject.cpp
index fe967e7906..965965487e 100644
--- a/src/opengl/qglframebufferobject.cpp
+++ b/src/opengl/qglframebufferobject.cpp
@@ -262,7 +262,7 @@ GLenum QGLFramebufferObjectFormat::internalFormat() const
 class QGLFramebufferObjectPrivate
 {
 public:
-    QGLFramebufferObjectPrivate() : depth_stencil_buffer(0), valid(false), bound(false), ctx(0), previous_fbo(0) {}
+    QGLFramebufferObjectPrivate() : depth_stencil_buffer(0), valid(false), bound(false), ctx(0), previous_fbo(0), engine(0) {}
     ~QGLFramebufferObjectPrivate() {}
 
     void init(const QSize& sz, QGLFramebufferObject::Attachment attachment,
@@ -280,6 +280,7 @@ public:
     QGLFramebufferObject::Attachment fbo_attachment;
     QGLContext *ctx; // for Windows extension ptrs
     GLuint previous_fbo;
+    mutable QPaintEngine *engine;
 };
 
 bool QGLFramebufferObjectPrivate::checkFramebufferStatus() const
@@ -723,6 +724,8 @@ QGLFramebufferObject::~QGLFramebufferObject()
     Q_D(QGLFramebufferObject);
     QGL_FUNC_CONTEXT;
 
+    delete d->engine;
+
     if (isValid()
         && (d->ctx == QGLContext::currentContext()
             || qgl_share_reg()->checkSharing(d->ctx, QGLContext::currentContext())))
@@ -890,16 +893,32 @@ Q_GLOBAL_STATIC(QOpenGLPaintEngine, qt_buffer_engine)
 /*! \reimp */
 QPaintEngine *QGLFramebufferObject::paintEngine() const
 {
-#if defined(QT_OPENGL_ES_1) || defined(QT_OPENGL_ES_1_CL)
-    return qt_buffer_engine();
-#elif defined(QT_OPENGL_ES_2)
-    return qt_buffer_2_engine();
-#else
     Q_D(const QGLFramebufferObject);
-    if (qt_gl_preferGL2Engine())
-        return qt_buffer_2_engine();
-    else
-        return qt_buffer_engine();
+    if (d->engine)
+        return d->engine;
+
+#if !defined(QT_OPENGL_ES_1) && !defined(QT_OPENGL_ES_1_CL)
+#if !defined (QT_OPENGL_ES_2)
+    if (qt_gl_preferGL2Engine()) {
+#endif
+        QPaintEngine *engine = qt_buffer_2_engine();
+        if (engine->isActive() && engine->paintDevice() != this) {
+            d->engine = new QGL2PaintEngineEx;
+            return d->engine;
+        }
+        return engine;
+#if !defined (QT_OPENGL_ES_2)
+    }
+#endif
+#endif
+
+#if !defined(QT_OPENGL_ES_2)
+    QPaintEngine *engine = qt_buffer_engine();
+    if (engine->isActive() && engine->paintDevice() != this) {
+        d->engine = new QOpenGLPaintEngine;
+        return d->engine;
+    }
+    return engine;
 #endif
 }