Create rendering framegraph only for required viewports

When in mono mode, left & right viewport trees are not required
at all and vice versa. So reparent subtrees when stereoscopic
mode is changed instead of just enabling/disabling cameras.

Task-number: QT3DS-2591
Change-Id: I23bae7b9808fb786c59549a1afad8ee49fde533e
Reviewed-by: Tomi Korpipää <tomi.korpipaa@qt.io>
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

2 files changed, 16 insertions, 16 deletions

diff --git a/src/runtime/q3dsscenemanager.cpp b/src/runtime/q3dsscenemanager.cpp
index cf2f2e7..ef1b1b7 100644
--- a/src/runtime/q3dsscenemanager.cpp
+++ b/src/runtime/q3dsscenemanager.cpp
@@ -1185,17 +1185,17 @@ void Q3DSSceneManager::updateViewportRects()
     m_stereoMode->setValue(m_engine->viewportSettings()->stereoMode());
 }
 
-void Q3DSSceneManager::updateCamerasStatus(Q3DSLayerAttached *layerData)
+void Q3DSSceneManager::updateViewportsRenderTree(Q3DSLayerAttached *layerData, ViewportSet viewports)
 {
     Q_ASSERT(layerData);
     if (m_engine->isStereoscopic()) {
-        layerData->eyeMono->cameraSelector->setEnabled(false);
-        layerData->eyeLeft->cameraSelector->setEnabled(true);
-        layerData->eyeRight->cameraSelector->setEnabled(true);
+        viewports.viewportMono->setParent(layerData->layerFgDummyParent);
+        viewports.viewportLeft->setParent(layerData->eyeLeft->rtSelector);
+        viewports.viewportRight->setParent(layerData->eyeRight->rtSelector);
     } else {
-        layerData->eyeMono->cameraSelector->setEnabled(true);
-        layerData->eyeLeft->cameraSelector->setEnabled(false);
-        layerData->eyeRight->cameraSelector->setEnabled(false);
+        viewports.viewportMono->setParent(layerData->eyeMono->rtSelector);
+        viewports.viewportLeft->setParent(layerData->layerFgDummyParent);
+        viewports.viewportRight->setParent(layerData->layerFgDummyParent);
     }
 }
 
@@ -1342,7 +1342,7 @@ void Q3DSSceneManager::buildLayer(Q3DSLayerNode *layer3DS,
                                "RT for layer %s", layer3DS->id().constData());
     rtSelector->setTarget(rt);
 
-    viewports.viewportMono = new Qt3DRender::QViewport(rtSelector);
+    viewports.viewportMono = new Qt3DRender::QViewport(); // Will be reparented
     layerData->eyeMono = buildEye(layer3DS, viewports.viewportMono);
 
     // Create color and depth-stencil buffers for this layer
@@ -1354,7 +1354,7 @@ void Q3DSSceneManager::buildLayer(Q3DSLayerNode *layer3DS,
                                "RT for layer %s", layer3DS->id().constData());
     rtSelectorLeft->setTarget(rtLeft);
 
-    viewports.viewportLeft = new Qt3DRender::QViewport(rtSelectorLeft);
+    viewports.viewportLeft = new Qt3DRender::QViewport(); // Will be reparented
     layerData->eyeLeft = buildEye(layer3DS, viewports.viewportLeft);
 
     // Create color and depth-stencil buffers for this layer
@@ -1366,7 +1366,7 @@ void Q3DSSceneManager::buildLayer(Q3DSLayerNode *layer3DS,
                                "RT for layer %s", layer3DS->id().constData());
     rtSelectorRight->setTarget(rtRight);
 
-    viewports.viewportRight = new Qt3DRender::QViewport(rtSelectorRight);
+    viewports.viewportRight = new Qt3DRender::QViewport(); // Will be reparented
     layerData->eyeRight = buildEye(layer3DS, viewports.viewportRight);
 
     // Note: Moved layerSceneRootEntity to be child of layerFgRoot instead of rtSelector
@@ -1420,8 +1420,8 @@ void Q3DSSceneManager::buildLayer(Q3DSLayerNode *layer3DS,
     layerData->eyeLeft->effectData.effectRoot = layerData->eyeLeft->effectRoot;
     layerData->eyeRight->effectData.effectRoot = layerData->eyeRight->effectRoot;
 
-    // Enable/disable correct cameras depending on mode
-    updateCamerasStatus(layerData);
+    // Enable/disable correct viewports depending on mode
+    updateViewportsRenderTree(layerData, viewports);
 
     m_stereoMode = new Qt3DRender::QParameter(QLatin1String("stereoMode"),
                                               m_engine->viewportSettings()->stereoMode());
@@ -1451,7 +1451,7 @@ void Q3DSSceneManager::buildLayer(Q3DSLayerNode *layer3DS,
     });
 
     QObject::connect(m_engine, &Q3DSEngine::stereoscopicChanged,
-                     [this, layer3DS, layerData]()
+                     [this, layer3DS, layerData, viewports]()
     {
         // When switching between stereo <-> non-stereo, update used shader
         // TODO: Here we disable effects when rendering stereo as msaa+effect currently doesn't work for stereo
@@ -1462,8 +1462,8 @@ void Q3DSSceneManager::buildLayer(Q3DSLayerNode *layer3DS,
         updateAdvancedBlendLayers();
 
         updateLayerCompositorProgram(layer3DS);
-        // And enable/disable related cameras
-        updateCamerasStatus(layerData);
+        // And enable/disable related viewports
+        updateViewportsRenderTree(layerData, viewports);
     });
 
     layer3DS->setAttached(layerData);
diff --git a/src/runtime/q3dsscenemanager_p.h b/src/runtime/q3dsscenemanager_p.h
index cbeac36..bdc713f 100644
--- a/src/runtime/q3dsscenemanager_p.h
+++ b/src/runtime/q3dsscenemanager_p.h
@@ -810,7 +810,7 @@ private:
     void updateSubPresentationHosts();
     void loadSubUipPresentation(Q3DSSubPresentation *sp);
     void initSubTree(Q3DSGraphObject *subTreeRoot);
-    void updateCamerasStatus(Q3DSLayerAttached *layerData);
+    void updateViewportsRenderTree(Q3DSLayerAttached *layerData, ViewportSet viewports);
     Q3DSEyeData *buildEye(Q3DSLayerNode *layer3DS, Qt3DRender::QViewport *viewport);
     void buildLayer(Q3DSLayerNode *layer3DS, Qt3DRender::QFrameGraphNode *parent, const QSize &parentSize);
     void buildSubPresentationLayer(Q3DSLayerNode *layer3DS, const QSize &parentSize);