6 files changed, 58 insertions, 7 deletions

diff --git a/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp b/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
index 211fad267f..8cd26f1ea4 100644
--- a/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
+++ b/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
@@ -167,6 +167,8 @@ void QGLTextureGlyphCache::resizeTextureData(int width, int height)
     // ### the QTextureGlyphCache API needs to be reworked to allow
     // ### resizeTextureData to fail
 
+    ctx->d_ptr->refreshCurrentFbo();
+
     funcs->glBindFramebuffer(GL_FRAMEBUFFER, m_textureResource->m_fbo);
 
     GLuint tmp_texture;
diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 1e49d95087..35f08e0092 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -510,6 +510,35 @@ void QGLContextPrivate::setupSharing() {
     }
 }
 
+void QGLContextPrivate::refreshCurrentFbo()
+{
+    QOpenGLContextPrivate *guiGlContextPrivate =
+        guiGlContext ? QOpenGLContextPrivate::get(guiGlContext) : 0;
+
+    // if QOpenGLFramebufferObjects have been used in the mean-time, we've lost our cached value
+    if (guiGlContextPrivate && guiGlContextPrivate->qgl_current_fbo_invalid) {
+        GLint current;
+        QOpenGLFunctions *funcs = qgl_functions();
+        funcs->glGetIntegerv(GL_FRAMEBUFFER_BINDING, &current);
+
+        current_fbo = current;
+
+        guiGlContextPrivate->qgl_current_fbo_invalid = false;
+    }
+}
+
+void QGLContextPrivate::setCurrentFbo(GLuint fbo)
+{
+    current_fbo = fbo;
+
+    QOpenGLContextPrivate *guiGlContextPrivate =
+        guiGlContext ? QOpenGLContextPrivate::get(guiGlContext) : 0;
+
+    if (guiGlContextPrivate)
+        guiGlContextPrivate->qgl_current_fbo_invalid = false;
+}
+
+
 /*!
     \fn bool QGLFormat::doubleBuffer() const
 
diff --git a/src/opengl/qgl_p.h b/src/opengl/qgl_p.h
index c4151a3d34..4cf656fd86 100644
--- a/src/opengl/qgl_p.h
+++ b/src/opengl/qgl_p.h
@@ -238,6 +238,8 @@ public:
     bool ownContext;
 
     void setupSharing();
+    void refreshCurrentFbo();
+    void setCurrentFbo(GLuint fbo);
 
     QGLFormat glFormat;
     QGLFormat reqFormat;
diff --git a/src/opengl/qglframebufferobject.cpp b/src/opengl/qglframebufferobject.cpp
index 4ef50e9334..49b28c36b9 100644
--- a/src/opengl/qglframebufferobject.cpp
+++ b/src/opengl/qglframebufferobject.cpp
@@ -472,6 +472,8 @@ void QGLFramebufferObjectPrivate::init(QGLFramebufferObject *q, const QSize &sz,
     if (!funcs.hasOpenGLFeature(QOpenGLFunctions::Framebuffers))
         return;
 
+    ctx->d_ptr->refreshCurrentFbo();
+
     size = sz;
     target = texture_target;
     // texture dimensions
@@ -1027,7 +1029,7 @@ bool QGLFramebufferObject::bind()
     d->funcs.glBindFramebuffer(GL_FRAMEBUFFER, d->fbo());
     d->valid = d->checkFramebufferStatus();
     if (d->valid && current)
-        current->d_ptr->current_fbo = d->fbo();
+        current->d_ptr->setCurrentFbo(d->fbo());
     return d->valid;
 }
 
@@ -1060,7 +1062,7 @@ bool QGLFramebufferObject::release()
 #endif
 
     if (current) {
-        current->d_ptr->current_fbo = current->d_ptr->default_fbo;
+        current->d_ptr->setCurrentFbo(current->d_ptr->default_fbo);
         d->funcs.glBindFramebuffer(GL_FRAMEBUFFER, current->d_ptr->default_fbo);
     }
 
@@ -1173,7 +1175,7 @@ bool QGLFramebufferObject::bindDefault()
         if (!functions.hasOpenGLFeature(QOpenGLFunctions::Framebuffers))
             return false;
 
-        ctx->d_ptr->current_fbo = ctx->d_ptr->default_fbo;
+        ctx->d_ptr->setCurrentFbo(ctx->d_ptr->default_fbo);
         functions.glBindFramebuffer(GL_FRAMEBUFFER, ctx->d_ptr->default_fbo);
 #ifdef QT_DEBUG
     } else {
@@ -1320,7 +1322,12 @@ bool QGLFramebufferObject::isBound() const
 {
     Q_D(const QGLFramebufferObject);
     const QGLContext *current = QGLContext::currentContext();
-    return current ? current->d_ptr->current_fbo == d->fbo() : false;
+    if (current) {
+        current->d_ptr->refreshCurrentFbo();
+        return current->d_ptr->current_fbo == d->fbo();
+    }
+
+    return false;
 }
 
 /*!
@@ -1400,6 +1407,8 @@ void QGLFramebufferObject::blitFramebuffer(QGLFramebufferObject *target, const Q
     const int ty0 = th - (targetRect.top() + targetRect.height());
     const int ty1 = th - targetRect.top();
 
+    ctx->d_ptr->refreshCurrentFbo();
+
     functions.glBindFramebuffer(GL_READ_FRAMEBUFFER, source ? source->handle() : 0);
     functions.glBindFramebuffer(GL_DRAW_FRAMEBUFFER, target ? target->handle() : 0);
 
diff --git a/src/opengl/qglpaintdevice.cpp b/src/opengl/qglpaintdevice.cpp
index 40cc7bb71d..c07d0a761b 100644
--- a/src/opengl/qglpaintdevice.cpp
+++ b/src/opengl/qglpaintdevice.cpp
@@ -74,6 +74,8 @@ void QGLPaintDevice::beginPaint()
     QGLContext *ctx = context();
     ctx->makeCurrent();
 
+    ctx->d_func()->refreshCurrentFbo();
+
     // Record the currently bound FBO so we can restore it again
     // in endPaint() and bind this device's FBO
     //
@@ -85,7 +87,7 @@ void QGLPaintDevice::beginPaint()
     m_previousFBO = ctx->d_func()->current_fbo;
 
     if (m_previousFBO != m_thisFBO) {
-        ctx->d_ptr->current_fbo = m_thisFBO;
+        ctx->d_func()->setCurrentFbo(m_thisFBO);
         ctx->contextHandle()->functions()->glBindFramebuffer(GL_FRAMEBUFFER, m_thisFBO);
     }
 
@@ -102,8 +104,10 @@ void QGLPaintDevice::ensureActiveTarget()
     if (ctx != QGLContext::currentContext())
         ctx->makeCurrent();
 
+    ctx->d_func()->refreshCurrentFbo();
+
     if (ctx->d_ptr->current_fbo != m_thisFBO) {
-        ctx->d_ptr->current_fbo = m_thisFBO;
+        ctx->d_func()->setCurrentFbo(m_thisFBO);
         ctx->contextHandle()->functions()->glBindFramebuffer(GL_FRAMEBUFFER, m_thisFBO);
     }
 
@@ -114,8 +118,11 @@ void QGLPaintDevice::endPaint()
 {
     // Make sure the FBO bound at beginPaint is re-bound again here:
     QGLContext *ctx = context();
+
+    ctx->d_func()->refreshCurrentFbo();
+
     if (m_previousFBO != ctx->d_func()->current_fbo) {
-        ctx->d_ptr->current_fbo = m_previousFBO;
+        ctx->d_func()->setCurrentFbo(m_previousFBO);
         ctx->contextHandle()->functions()->glBindFramebuffer(GL_FRAMEBUFFER, m_previousFBO);
     }
 
diff --git a/src/opengl/qglpixelbuffer.cpp b/src/opengl/qglpixelbuffer.cpp
index 56bfaebe4f..63b624aea2 100644
--- a/src/opengl/qglpixelbuffer.cpp
+++ b/src/opengl/qglpixelbuffer.cpp
@@ -344,6 +344,8 @@ void QGLPixelBuffer::updateDynamicTexture(GLuint texture_id) const
 
     QOpenGLExtensions extensions(ctx->contextHandle());
 
+    ctx->d_ptr->refreshCurrentFbo();
+
     if (d->blit_fbo) {
         QOpenGLFramebufferObject::blitFramebuffer(d->blit_fbo, d->fbo);
         extensions.glBindFramebuffer(GL_READ_FRAMEBUFFER, d->blit_fbo->handle());