6 files changed, 46 insertions, 3 deletions

diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 2d90342..4c152e2 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -1297,6 +1297,7 @@ void QGLContextPrivate::init(QPaintDevice *dev, const QGLFormat &format)
     max_texture_size = -1;
     version_flags_cached = false;
     version_flags = QGLFormat::OpenGL_Version_None;
+    current_fbo = 0;
 }
 
 QGLContext* QGLContext::currentCtx = 0;
diff --git a/src/opengl/qgl.h b/src/opengl/qgl.h
index 01b1d6f..32fbce2 100644
--- a/src/opengl/qgl.h
+++ b/src/opengl/qgl.h
@@ -371,8 +371,8 @@ private:
     friend class QMacGLWindowChangeEvent;
     friend QGLContextPrivate *qt_phonon_get_dptr(const QGLContext *);
 #endif
-#ifdef Q_WS_WIN
     friend class QGLFramebufferObject;
+#ifdef Q_WS_WIN
     friend class QGLFramebufferObjectPrivate;
     friend bool qt_resolve_GLSL_functions(QGLContext *ctx);
     friend bool qt_createGLSLProgram(QGLContext *ctx, GLuint &program, const char *shader_src, GLuint &shader);
diff --git a/src/opengl/qgl_p.h b/src/opengl/qgl_p.h
index b8bbeaf..b15eebc 100644
--- a/src/opengl/qgl_p.h
+++ b/src/opengl/qgl_p.h
@@ -254,6 +254,8 @@ public:
     QGLExtensionFuncs extensionFuncs;
     GLint max_texture_size;
 
+    GLuint current_fbo;
+
 #ifdef Q_WS_WIN
     static inline QGLExtensionFuncs& qt_get_extension_funcs(const QGLContext *ctx) { return ctx->d_ptr->extensionFuncs; }
 #endif
@@ -267,7 +269,7 @@ public:
 };
 
 // ### make QGLContext a QObject in 5.0 and remove the proxy stuff
-class QGLSignalProxy : public QObject
+class Q_OPENGL_EXPORT QGLSignalProxy : public QObject
 {
     Q_OBJECT
 public:
diff --git a/src/opengl/qglframebufferobject.cpp b/src/opengl/qglframebufferobject.cpp
index fb22272..8524dfa 100644
--- a/src/opengl/qglframebufferobject.cpp
+++ b/src/opengl/qglframebufferobject.cpp
@@ -66,7 +66,7 @@ extern QImage qt_gl_read_framebuffer(const QSize&, bool, bool);
 class QGLFramebufferObjectPrivate
 {
 public:
-    QGLFramebufferObjectPrivate() : depth_stencil_buffer(0), valid(false), bound(false), ctx(0) {}
+    QGLFramebufferObjectPrivate() : depth_stencil_buffer(0), valid(false), bound(false), ctx(0), previous_fbo(0) {}
     ~QGLFramebufferObjectPrivate() {}
 
     void init(const QSize& sz, QGLFramebufferObject::Attachment attachment,
@@ -81,6 +81,7 @@ public:
     uint bound : 1;
     QGLFramebufferObject::Attachment fbo_attachment;
     QGLContext *ctx; // for Windows extension ptrs
+    GLuint previous_fbo;
 };
 
 bool QGLFramebufferObjectPrivate::checkFramebufferStatus() const
@@ -469,6 +470,15 @@ bool QGLFramebufferObject::isValid() const
     Switches rendering from the default, windowing system provided
     framebuffer to this framebuffer object.
     Returns true upon success, false otherwise.
+
+    Since 4.6: if another QGLFramebufferObject instance was already bound
+    to the current context, then its handle() will be remembered and
+    automatically restored when release() is called.  This allows multiple
+    framebuffer rendering targets to be stacked up.  It is important that
+    release() is called on the stacked framebuffer objects in the reverse
+    order of the calls to bind().
+
+    \sa release()
 */
 bool QGLFramebufferObject::bind()
 {
@@ -478,6 +488,12 @@ bool QGLFramebufferObject::bind()
     QGL_FUNC_CONTEXT;
     glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, d->fbo);
     d->bound = d->valid = d->checkFramebufferStatus();
+    const QGLContext *context = QGLContext::currentContext();
+    if (d->valid && context) {
+        // Save the previous setting to automatically restore in release().
+        d->previous_fbo = context->d_ptr->current_fbo;
+        context->d_ptr->current_fbo = d->fbo;
+    }
     return d->valid;
 }
 
@@ -487,6 +503,12 @@ bool QGLFramebufferObject::bind()
     Switches rendering back to the default, windowing system provided
     framebuffer.
     Returns true upon success, false otherwise.
+
+    Since 4.6: if another QGLFramebufferObject instance was already bound
+    to the current context when bind() was called, then this function will
+    automatically re-bind it to the current context.
+
+    \sa bind()
 */
 bool QGLFramebufferObject::release()
 {
@@ -497,6 +519,14 @@ bool QGLFramebufferObject::release()
     glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
     d->valid = d->checkFramebufferStatus();
     d->bound = false;
+    const QGLContext *context = QGLContext::currentContext();
+    if (d->valid && context) {
+        // Restore the previous setting for stacked framebuffer objects.
+        context->d_ptr->current_fbo = d->previous_fbo;
+        if (d->previous_fbo)
+            glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, d->previous_fbo);
+        d->previous_fbo = 0;
+    }
     return d->valid;
 }
 
diff --git a/src/opengl/qpixmapdata_gl.cpp b/src/opengl/qpixmapdata_gl.cpp
index 5d668cd..b079557 100644
--- a/src/opengl/qpixmapdata_gl.cpp
+++ b/src/opengl/qpixmapdata_gl.cpp
@@ -205,6 +205,14 @@ void QGLPixmapData::fromImage(const QImage &image,
     m_dirty = true;
 }
 
+bool QGLPixmapData::scroll(int dx, int dy, const QRect &rect)
+{
+    Q_UNUSED(dx);
+    Q_UNUSED(dy);
+    Q_UNUSED(rect);
+    return false;
+}
+
 void QGLPixmapData::fill(const QColor &color)
 {
     if (!isValid())
diff --git a/src/opengl/qpixmapdata_gl_p.h b/src/opengl/qpixmapdata_gl_p.h
index 63703fd..e450f01 100644
--- a/src/opengl/qpixmapdata_gl_p.h
+++ b/src/opengl/qpixmapdata_gl_p.h
@@ -73,6 +73,8 @@ public:
     void fromImage(const QImage &image,
                    Qt::ImageConversionFlags flags);
 
+    bool scroll(int dx, int dy, const QRect &rect);
+
     void fill(const QColor &color);
     bool hasAlphaChannel() const;
     QImage toImage() const;