From 1a5606a45cd6cd4f21b5afe3a75432a3e2c302ac Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Fri, 13 Oct 2023 23:33:03 +0200
Subject: [PATCH] Improve collision data cooking usability

#1687
---
 Source/Engine/Graphics/Models/Mesh.cpp     |  2 +-
 Source/Engine/Physics/CollisionCooking.cpp |  6 ++++++
 Source/Engine/Physics/CollisionData.cpp    | 14 ++++++--------
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/Source/Engine/Graphics/Models/Mesh.cpp b/Source/Engine/Graphics/Models/Mesh.cpp
index f03c013c6..1e531d0e0 100644
--- a/Source/Engine/Graphics/Models/Mesh.cpp
+++ b/Source/Engine/Graphics/Models/Mesh.cpp
@@ -609,7 +609,7 @@ bool Mesh::DownloadDataCPU(MeshBufferType type, BytesContainer& result, int32& c
         ScopeLock lock(model->Locker);
         if (model->IsVirtual())
         {
-            LOG(Error, "Cannot access CPU data of virtual models. Use GPU data download");
+            LOG(Error, "Cannot access CPU data of virtual models. Use GPU data download.");
             return true;
         }
 
diff --git a/Source/Engine/Physics/CollisionCooking.cpp b/Source/Engine/Physics/CollisionCooking.cpp
index dc2c42584..4c8cffdcc 100644
--- a/Source/Engine/Physics/CollisionCooking.cpp
+++ b/Source/Engine/Physics/CollisionCooking.cpp
@@ -127,6 +127,8 @@ bool CollisionCooking::CookCollision(const Argument& arg, CollisionData::Seriali
                 const auto& mesh = *meshes[i];
                 if ((arg.MaterialSlotsMask & (1 << mesh.GetMaterialSlotIndex())) == 0)
                     continue;
+                if (mesh.GetVertexCount() == 0)
+                    continue;
 
                 int32 count;
                 if (mesh.DownloadDataCPU(MeshBufferType::Vertex0, vertexBuffers[i], count))
@@ -159,6 +161,8 @@ bool CollisionCooking::CookCollision(const Argument& arg, CollisionData::Seriali
                 const auto& mesh = *meshes[i];
                 if ((arg.MaterialSlotsMask & (1 << mesh.GetMaterialSlotIndex())) == 0)
                     continue;
+                if (mesh.GetVertexCount() == 0)
+                    continue;
 
                 auto task = mesh.DownloadDataGPUAsync(MeshBufferType::Vertex0, vertexBuffers[i]);
                 if (task == nullptr)
@@ -208,6 +212,8 @@ bool CollisionCooking::CookCollision(const Argument& arg, CollisionData::Seriali
 
             const int32 firstVertexIndex = vertexCounter;
             const int32 vertexCount = vertexCounts[i];
+            if (vertexCount == 0)
+                continue;
             Platform::MemoryCopy(finalVertexData.Get() + firstVertexIndex, vData.Get(), vertexCount * sizeof(Float3));
             vertexCounter += vertexCount;
 
diff --git a/Source/Engine/Physics/CollisionData.cpp b/Source/Engine/Physics/CollisionData.cpp
index 36f28c111..54a49671d 100644
--- a/Source/Engine/Physics/CollisionData.cpp
+++ b/Source/Engine/Physics/CollisionData.cpp
@@ -23,12 +23,16 @@ CollisionData::CollisionData(const SpawnParams& params, const AssetInfo* info)
 
 bool CollisionData::CookCollision(CollisionDataType type, ModelBase* modelObj, int32 modelLodIndex, uint32 materialSlotsMask, ConvexMeshGenerationFlags convexFlags, int32 convexVertexLimit)
 {
-    // Validate state
     if (!IsVirtual())
     {
         LOG(Warning, "Only virtual assets can be modified at runtime.");
         return true;
     }
+    if (IsInMainThread() && modelObj && modelObj->IsVirtual())
+    {
+        LOG(Error, "Cannot cook collision data for virtual models on a main thread (virtual models data is stored on GPU only). Use thread pool or async task.");
+        return true;
+    }
 
     // Prepare
     CollisionCooking::Argument arg;
@@ -43,18 +47,12 @@ bool CollisionData::CookCollision(CollisionDataType type, ModelBase* modelObj, i
     SerializedOptions options;
     BytesContainer outputData;
     if (CollisionCooking::CookCollision(arg, options, outputData))
-    {
         return true;
-    }
-
-    // Clear state
-    unload(true);
 
     // Load data
+    unload(true);
     if (load(&options, outputData.Get(), outputData.Length()) != LoadResult::Ok)
-    {
         return true;
-    }
 
     // Mark as loaded (eg. Mesh Colliders using this asset will update shape for physics simulation)
     onLoaded();