Merge fix-7.3.5 to master (#2157)

* Fix handling of hydra updates in batch renders (#2155)

* Fix missing updates in husk #2154

* Update changelog

* Rename function for clarity

* Update changelog

CHANGELOG.md

@@ -1,7 +1,7 @@
 <!-- SPDX-License-Identifier: Apache-2.0 -->
 # Changelog
 
-## Pending feature release
+## Pending Feature release
 
 ### Feature
 - [usd#2119](https://github.com/Autodesk/arnold-usd/issues/2119) - Support options shader_override attribute
@@ -15,7 +15,7 @@
 - [usd#2133](https://github.com/Autodesk/arnold-usd/issues/2133) - Fixed crash when the root primitive is invalid
 - [usd#2122](https://github.com/Autodesk/arnold-usd/issues/2122) - RectLight doesn't take width / height into account with scenes exported from Arnold
 - [usd#1764](https://github.com/Autodesk/arnold-usd/issues/1764) - ArnoldUsd schema was missing from Arnold SDK
-
+- [usd#2154](https://github.com/Autodesk/arnold-usd/issues/2154) - Husk renders can miss scene updates
 
 ## [7.3.5.0] - 2024-11-08
 

libs/render_delegate/reader.cpp

@@ -223,8 +223,8 @@ void HydraArnoldReader::ReadStage(UsdStageRefPtr stage,
     arnoldRenderDelegate->SetRenderTags(purpose);
 
     // The scene might not be up to date, because of light links, etc, that were generated during the first sync.
-    // UpdateSceneChanges updates the dirtybits for a resync, this is how it works in our hydra render pass.
-    while (arnoldRenderDelegate->UpdateSceneChanges(_renderIndex, _shutter)) {
+    // HasPendingChanges updates the dirtybits for a resync, this is how it works in our hydra render pass.
+    while (arnoldRenderDelegate->HasPendingChanges(_renderIndex, _shutter)) {
         _renderIndex->SyncAll(&_tasks, &_taskContext);
     }
 }
@@ -251,7 +251,7 @@ void HydraArnoldReader::Update()
 {
     HdArnoldRenderDelegate *arnoldRenderDelegate = static_cast<HdArnoldRenderDelegate*>(_renderDelegate);
     _imagingDelegate->ApplyPendingUpdates();
-    arnoldRenderDelegate->UpdateSceneChanges(_renderIndex, _shutter);
+    arnoldRenderDelegate->HasPendingChanges(_renderIndex, _shutter);
     _renderIndex->SyncAll(&_tasks, &_taskContext);
 }
 

libs/render_delegate/render_delegate.cpp

@@ -460,7 +460,8 @@ HdArnoldRenderDelegate::HdArnoldRenderDelegate(bool isBatch, const TfToken &cont
     _context(context),
     _universe(universe),
     _procParent(nullptr),
-    _renderDelegateOwnsUniverse(universe==nullptr)
+    _renderDelegateOwnsUniverse(universe==nullptr),
+    _renderSessionType(renderSessionType)
 {    
 
     _lightLinkingChanged.store(false, std::memory_order_release);
@@ -485,7 +486,7 @@ HdArnoldRenderDelegate::HdArnoldRenderDelegate(bool isBatch, const TfToken &cont
         AiADPAddProductMetadata(AI_ADP_PLUGINVERSION, AtString{AI_VERSION});
         AiADPAddProductMetadata(AI_ADP_HOSTNAME, AtString{"Hydra"});
         AiADPAddProductMetadata(AI_ADP_HOSTVERSION, AtString{PXR_VERSION_STR});
-        AiBegin(renderSessionType);
+        AiBegin(_renderSessionType);
     }
     _supportedRprimTypes = {HdPrimTypeTokens->mesh, HdPrimTypeTokens->volume, HdPrimTypeTokens->points,
                             HdPrimTypeTokens->basisCurves, str::t_procedural_custom};
@@ -563,7 +564,7 @@ HdArnoldRenderDelegate::HdArnoldRenderDelegate(bool isBatch, const TfToken &cont
 
     if (_renderDelegateOwnsUniverse) {
         _universe = AiUniverse();
-        _renderSession = AiRenderSession(_universe, renderSessionType);
+        _renderSession = AiRenderSession(_universe, _renderSessionType);
     }
 
     _renderParam.reset(new HdArnoldRenderParam(this));
@@ -1532,14 +1533,15 @@ void HdArnoldRenderDelegate::ProcessConnections()
 bool HdArnoldRenderDelegate::CanUpdateScene()
 {
     // For interactive renders, it is always possible to update the scene
-    if (!_isBatch)
+    if (_renderSessionType == AI_SESSION_INTERACTIVE)
         return true;
     // For batch renders, only update the scene if the render hasn't started yet,
     // or if it's finished
     const int status = AiRenderGetStatus(_renderSession);
     return status != AI_RENDER_STATUS_RESTARTING && status != AI_RENDER_STATUS_RENDERING;
 }
-bool HdArnoldRenderDelegate::UpdateSceneChanges(HdRenderIndex* renderIndex, const GfVec2f& shutter)
+
+bool HdArnoldRenderDelegate::HasPendingChanges(HdRenderIndex* renderIndex, const GfVec2f& shutter)
 {
     HdDirtyBits bits = HdChangeTracker::Clean;
     // If Light Linking have changed, we have to dirty the categories on all rprims to force updating the

libs/render_delegate/render_delegate.h

@@ -327,15 +327,15 @@ class HdArnoldRenderDelegate final : public HdRenderDelegate {
     HDARNOLD_API
     void ApplyLightLinking(HdSceneDelegate *delegate, AtNode* node, SdfPath const& id);
 
-    /// Updates the eventual changes that happened in the input scene
-    /// since the last iteration.
+    /// Eventually mark some hydra primitives as being dirty
+    /// in which case we'll have another sync iteration pending
     ///
     /// @param renderIndex Pointer to the Hydra Render Index.
     /// @param shutterOpen Shutter Open value of the active camera.
     /// @param shutterClose Shutter Close value of the active camera.
-    /// @return True if the iteration contains scene changes.
+    /// @return True if hydra has pending changes.
     HDARNOLD_API
-    bool UpdateSceneChanges(HdRenderIndex* renderIndex, const GfVec2f& shutter);
+    bool HasPendingChanges(HdRenderIndex* renderIndex, const GfVec2f& shutter);
 
     /// Returns whether the Arnold scene can be updated or
     /// if Hydra changes should be ignored.
@@ -728,6 +728,7 @@ class HdArnoldRenderDelegate final : public HdRenderDelegate {
     AtNode* _fallbackShader = nullptr;   ///< Pointer to the fallback Arnold Shader.
     AtNode* _fallbackVolumeShader = nullptr; ///< Pointer to the fallback Arnold Volume Shader.
     AtNode* _procParent = nullptr;
+    AtSessionMode _renderSessionType = AI_SESSION_INTERACTIVE;
     std::string _logFile;
     std::string _statsFile;
     AtStatsMode _statsMode;

libs/render_delegate/render_pass.cpp

@@ -970,10 +970,16 @@ void HdArnoldRenderPass::_Execute(const HdRenderPassStateSharedPtr& renderPassSt
         clearBuffers(_renderBuffers);
     }
 
-    _renderDelegate->UpdateSceneChanges(
+    // Check if hydra still has pending changes that will be processed in the next iteration.
+    bool hasPendingChanges = _renderDelegate->HasPendingChanges(
         GetRenderIndex(),
         {AiNodeGetFlt(currentCamera, str::shutter_start), AiNodeGetFlt(currentCamera, str::shutter_end)});
-    const auto renderStatus = renderParam->UpdateRender();
+
+    // If we still have pending Hydra changes, we don't want to start / update the render just yet,
+    // as we'll receive shortly another sync. In particular in the case of batch renders, this prevents
+    // from rendering the final scene #2154
+    const auto renderStatus = hasPendingChanges ? 
+        HdArnoldRenderParam::Status::Converging : renderParam->UpdateRender();
     _isConverged = renderStatus != HdArnoldRenderParam::Status::Converging;
 
     // We need to set the converged status of the render buffers.