From afe77aa646408700d064025c2eaee08133dd2fc8 Mon Sep 17 00:00:00 2001
From: Miikka Heikkinen <miikka.heikkinen@qt.io>
Date: Thu, 18 Nov 2021 14:36:10 +0200
Subject: [PATCH] QmlDesigner: Fix 3D edit view rendering logic

If we have more than one render in queue for 3D edit view, we know the
current render is not good, so do not send it to creator side but
instead wait until we have just one render in the queue.

Also changed the timeout for queued renders to closely correspond to
60fps frame time as there is no point rendering any faster than that.
This also means we never need to queue more than two frames to ensure
correct results.

Fixes: QDS-5467
Change-Id: I49a3a7aeaff24484f48784d0391414165ce50748
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
---
 .../qt5informationnodeinstanceserver.cpp      | 40 ++++++++++++-------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/share/qtcreator/qml/qmlpuppet/qml2puppet/instances/qt5informationnodeinstanceserver.cpp b/share/qtcreator/qml/qmlpuppet/qml2puppet/instances/qt5informationnodeinstanceserver.cpp
index b1c211b6f84..545457ccbec 100644
--- a/share/qtcreator/qml/qmlpuppet/qml2puppet/instances/qt5informationnodeinstanceserver.cpp
+++ b/share/qtcreator/qml/qmlpuppet/qml2puppet/instances/qt5informationnodeinstanceserver.cpp
@@ -893,19 +893,31 @@ void Qt5InformationNodeInstanceServer::doRender3DEditView()
         // Key number is selected so that it is unlikely to conflict other ImageContainer use.
         auto imgContainer = ImageContainer(-1, renderImage, 2100000000);
 
-        // send the rendered image to creator process
-        nodeInstanceClient()->handlePuppetToCreatorCommand({PuppetToCreatorCommand::Render3DView,
-                                                            QVariant::fromValue(imgContainer)});
+        // If we have only one or no render queued, send the result to the creator side.
+        // Otherwise, we'll hold on that until we have rendered all pending frames to ensure sent
+        // results are correct.
+        if (m_need3DEditViewRender <= 1) {
+            nodeInstanceClient()->handlePuppetToCreatorCommand({PuppetToCreatorCommand::Render3DView,
+                                                                QVariant::fromValue(imgContainer)});
+#ifdef QUICK3D_PARTICLES_MODULE
+            if (m_need3DEditViewRender == 0 && ViewConfig::isParticleViewMode()
+                    && m_particleAnimationDriver && m_particleAnimationDriver->isAnimating()) {
+                m_need3DEditViewRender = 1;
+            }
+#endif
+        }
+
         if (m_need3DEditViewRender > 0) {
-            m_render3DEditViewTimer.start(0);
+            // We queue another render even if the requested render count was one, because another
+            // render is needed to ensure gizmo geometries are properly updated.
+            // Note that while in theory this seems that we shouldn't need to send the image to
+            // creator side when m_need3DEditViewRender is one, we need to do it to ensure
+            // smooth operation when objects are moved via drag, which triggers new renders
+            // continueously.
+            m_render3DEditViewTimer.start(17); // 16.67ms = ~60fps, rounds up to 17
             --m_need3DEditViewRender;
         }
-#ifdef QUICK3D_PARTICLES_MODULE
-        if (ViewConfig::isParticleViewMode()
-                && m_particleAnimationDriver && m_particleAnimationDriver->isAnimating()) {
-            m_need3DEditViewRender++;
-        }
-#endif
+
 #ifdef FPS_COUNTER
         // Force constant rendering for accurate fps count
         if (!m_render3DEditViewTimer.isActive())
@@ -1981,8 +1993,8 @@ void Qt5InformationNodeInstanceServer::view3DAction(const View3DActionCommand &c
         break;
     case View3DActionCommand::CameraToggle:
         updatedState.insert("usePerspective", command.isEnabled());
-        // It can take a couple frames to properly update icon gizmo positions, so render 3 frames
-        renderCount = 3;
+        // It can take a couple frames to properly update icon gizmo positions
+        renderCount = 2;
         break;
     case View3DActionCommand::OrientationToggle:
         updatedState.insert("globalOrientation", command.isEnabled());
@@ -2228,8 +2240,8 @@ void Qt5InformationNodeInstanceServer::update3DViewState(const Update3dViewState
             auto helper = qobject_cast<QmlDesigner::Internal::GeneralHelper *>(m_3dHelper);
             if (helper)
                 helper->storeToolState(helper->globalStateId(), helper->rootSizeKey(), QVariant(command.size()), 0);
-            // Queue three renders to make sure icon gizmos update properly
-            render3DEditView(3);
+            // Queue two renders to make sure all gizmos update properly
+            render3DEditView(2);
         }
     }
 #else