OnDemand rendering: only skip rendering jobs

As we still need to perform some of the jobs like picking,
buffer loading....

Change-Id: Ic771533b6f114400fa431f6de5ad8259a2a17c71
Task-number: QTBUG-60738
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

3 files changed, 27 insertions, 14 deletions

diff --git a/src/render/backend/nodemanagers.cpp b/src/render/backend/nodemanagers.cpp
index 2647bbb1a..80d0562b0 100644
--- a/src/render/backend/nodemanagers.cpp
+++ b/src/render/backend/nodemanagers.cpp
@@ -113,7 +113,6 @@ NodeManagers::~NodeManagers()
     delete m_layerManager;
     delete m_levelOfDetailManager;
     delete m_filterKeyManager;
-    delete m_frameGraphManager;
     delete m_transformManager;
     delete m_renderTargetManager;
     delete m_sceneManager;
@@ -127,6 +126,10 @@ NodeManagers::~NodeManagers()
     delete m_geometryManager;
     delete m_geometryRendererManager;
     delete m_objectPickerManager;
+
+    // Delete after m_objectPickerManager as that manager's shutdown needs to access
+    // the frame graph manager still.
+    delete m_frameGraphManager;
 //    delete m_boundingVolumeDebugManager;
     delete m_lightManager;
     delete m_environmentLightManager;
diff --git a/src/render/backend/renderer.cpp b/src/render/backend/renderer.cpp
index bd8687d5e..a68e5dccd 100644
--- a/src/render/backend/renderer.cpp
+++ b/src/render/backend/renderer.cpp
@@ -462,7 +462,9 @@ void Renderer::setSurfaceExposed(bool exposed)
 Render::FrameGraphNode *Renderer::frameGraphRoot() const
 {
     Q_ASSERT(m_settings);
-    return m_nodesManager->frameGraphManager()->lookupNode(m_settings->activeFrameGraphID());
+    if (m_nodesManager && m_nodesManager->frameGraphManager() && m_settings)
+        return m_nodesManager->frameGraphManager()->lookupNode(m_settings->activeFrameGraphID());
+    return nullptr;
 }
 
 // QAspectThread context
@@ -1390,12 +1392,6 @@ QVector<Qt3DCore::QAspectJobPtr> Renderer::renderBinJobs()
     for (const QAspectJobPtr &bufferJob : bufferJobs)
         m_calculateBoundingVolumeJob->addDependency(bufferJob);
 
-    // Set values on pickBoundingVolumeJob
-    m_pickBoundingVolumeJob->setFrameGraphRoot(frameGraphRoot());
-    m_pickBoundingVolumeJob->setRenderSettings(settings());
-    m_pickBoundingVolumeJob->setMouseEvents(pendingPickingEvents());
-    m_pickBoundingVolumeJob->setKeyEvents(pendingKeyEvents());
-
     m_updateLevelOfDetailJob->setFrameGraphRoot(frameGraphRoot());
     // Set dependencies of resource gatherer
     for (const QAspectJobPtr &jobPtr : renderBinJobs) {
@@ -1451,6 +1447,15 @@ QVector<Qt3DCore::QAspectJobPtr> Renderer::renderBinJobs()
 
 QAspectJobPtr Renderer::pickBoundingVolumeJob()
 {
+    // Set values on pickBoundingVolumeJob
+    RenderSettings *renderSetting = settings();
+    if (renderSetting != nullptr) {
+        m_pickBoundingVolumeJob->setRenderSettings(renderSetting);
+        m_pickBoundingVolumeJob->setFrameGraphRoot(frameGraphRoot());
+        m_pickBoundingVolumeJob->setMouseEvents(pendingPickingEvents());
+        m_pickBoundingVolumeJob->setKeyEvents(pendingKeyEvents());
+    }
+
     return m_pickBoundingVolumeJob;
 }
 
diff --git a/src/render/frontend/qrenderaspect.cpp b/src/render/frontend/qrenderaspect.cpp
index 1f88cb006..f7a2e2ffd 100644
--- a/src/render/frontend/qrenderaspect.cpp
+++ b/src/render/frontend/qrenderaspect.cpp
@@ -405,12 +405,6 @@ QVector<Qt3DCore::QAspectJobPtr> QRenderAspect::jobsToExecute(qint64 time)
     // asked for jobs to execute (this function). If that is the case, the RenderSettings will
     // be null and we should not generate any jobs.
     if (d->m_renderer->isRunning() && d->m_renderer->settings()) {
-        // don't spawn any jobs, if the renderer decides to skip this frame
-        if (!d->m_renderer->shouldRender()) {
-            d->m_renderer->skipNextFrame();
-            QThread::msleep(1);
-            return jobs;
-        }
 
         Render::NodeManagers *manager = d->m_renderer->nodeManagers();
         QAspectJobPtr textureLoadingSync = d->m_renderer->syncTextureLoadingJob();
@@ -448,8 +442,19 @@ QVector<Qt3DCore::QAspectJobPtr> QRenderAspect::jobsToExecute(qint64 time)
 
         // Add all jobs to queue
         const Qt3DCore::QAspectJobPtr pickBoundingVolumeJob = d->m_renderer->pickBoundingVolumeJob();
+        // Note: the getter is also responsible for returning a job ready to run
         jobs.append(pickBoundingVolumeJob);
 
+
+        // Don't spawn any rendering jobs, if the renderer decides to skip this frame
+        // Note: this only affects rendering jobs (jobs that load buffers,
+        // perform picking,... must still be run)
+        if (!d->m_renderer->shouldRender()) {
+            d->m_renderer->skipNextFrame();
+            QThread::msleep(1);
+            return jobs;
+        }
+
         // Traverse the current framegraph and create jobs to populate
         // RenderBins with RenderCommands
         // All jobs needed to create the frame and their dependencies are set by