Shader: check frontend node still exists before synching

Since backend shaders might outlive their frontend counterparts
when using the OpenGL renderer (we need 1 more frame to properly
cleanup shaders), check they still exists before trying to send
changes.

Also make sure we unset the send changes flag when we cleanup
a backend shader

Change-Id: I3d9cee13fa66e346e040f3be35de223c9081267e
Reviewed-by: Mike Krus <mike.krus@kdab.com>

2 files changed, 5 insertions, 0 deletions

diff --git a/src/plugins/renderers/opengl/renderer/renderer.cpp b/src/plugins/renderers/opengl/renderer/renderer.cpp
index 9f9253792..35f1d6bf4 100644
--- a/src/plugins/renderers/opengl/renderer/renderer.cpp
+++ b/src/plugins/renderers/opengl/renderer/renderer.cpp
@@ -1172,6 +1172,10 @@ void Renderer::sendShaderChangesToFrontend(Qt3DCore::QAspectManager *manager)
         Shader *s = m_nodesManager->shaderManager()->data(handle);
         if (s->requiresFrontendSync()) {
             QShaderProgram *frontend = static_cast<decltype(frontend)>(manager->lookupNode(s->peerId()));
+            // Could happen as a backend shader might live beyong the frontend
+            // the time needed to destroy the GLShader assoicated with it.
+            if (!frontend)
+                continue;
             QShaderProgramPrivate *dFrontend = static_cast<decltype(dFrontend)>(QNodePrivate::get(frontend));
             s->unsetRequiresFrontendSync();
             dFrontend->setStatus(s->status());
diff --git a/src/render/materialsystem/shader.cpp b/src/render/materialsystem/shader.cpp
index 43cf61cd3..343fbf3fe 100644
--- a/src/render/materialsystem/shader.cpp
+++ b/src/render/materialsystem/shader.cpp
@@ -102,6 +102,7 @@ void Shader::cleanup()
     m_status = QShaderProgram::NotReady;
     m_format = QShaderProgram::GLSL;
     m_log.clear();
+    m_requiresFrontendSync = false;
     m_dirty = false;
 }