Support shutting down the render thread without an OpenGL context.

[ChangeLog][QtQuick][SceneGraph] There might not be an OpenGL context
bound when QQuickWindow::sceneGraphInvalidated() is emitted if an
error occurs while cleaning up the scene graph (such as
EGL_CONTEXT_LOST). This is according to the documentation, but has
never occurred in practice before.

Change-Id: I13dbfbb4b6d0d27fa42fcb8b54df16ea02284807
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp b/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp
index 04f2bc891b..791e06ece2 100644
--- a/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp
+++ b/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp
@@ -836,10 +836,12 @@ static void qsg_wipeBatch(Batch *batch, QOpenGLFunctions *funcs)
 
 Renderer::~Renderer()
 {
-    // Clean up batches and buffers
-    for (int i=0; i<m_opaqueBatches.size(); ++i) qsg_wipeBatch(m_opaqueBatches.at(i), this);
-    for (int i=0; i<m_alphaBatches.size(); ++i) qsg_wipeBatch(m_alphaBatches.at(i), this);
-    for (int i=0; i<m_batchPool.size(); ++i) qsg_wipeBatch(m_batchPool.at(i), this);
+    if (QOpenGLContext::currentContext()) {
+        // Clean up batches and buffers
+        for (int i=0; i<m_opaqueBatches.size(); ++i) qsg_wipeBatch(m_opaqueBatches.at(i), this);
+        for (int i=0; i<m_alphaBatches.size(); ++i) qsg_wipeBatch(m_alphaBatches.at(i), this);
+        for (int i=0; i<m_batchPool.size(); ++i) qsg_wipeBatch(m_batchPool.at(i), this);
+    }
 
     // The shadowtree
     qDeleteAll(m_nodes.values());