From 88bd5b2534f48a39beb8c62d2e7b597d91b04414 Mon Sep 17 00:00:00 2001
From: Wojciech Figat <wojtek@figat.pl>
Date: Wed, 4 Jan 2023 12:06:56 +0100
Subject: [PATCH] Fix threading issues with GPU buffers mapping

---
 Source/Engine/Graphics/GPUDevice.cpp                   |  3 ++-
 .../GraphicsDevice/DirectX/DX11/GPUBufferDX11.cpp      | 10 ++++++++--
 .../Engine/GraphicsDevice/DirectX/DX11/GPUBufferDX11.h |  1 +
 .../GraphicsDevice/DirectX/DX12/GPUBufferDX12.cpp      |  3 ++-
 .../Engine/GraphicsDevice/DirectX/DX12/GPUBufferDX12.h |  2 +-
 Source/Engine/Renderer/GI/GlobalSurfaceAtlasPass.cpp   |  2 +-
 6 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/Source/Engine/Graphics/GPUDevice.cpp b/Source/Engine/Graphics/GPUDevice.cpp
index 432acc548..16f13d522 100644
--- a/Source/Engine/Graphics/GPUDevice.cpp
+++ b/Source/Engine/Graphics/GPUDevice.cpp
@@ -447,6 +447,8 @@ void GPUDevice::preDispose()
     SAFE_DELETE_GPU_RESOURCE(_res->PS_Clear);
     SAFE_DELETE_GPU_RESOURCE(_res->FullscreenTriangleVB);
 
+    Locker.Unlock();
+
     // Release GPU resources memory and unlink from device
     // Note: after that no GPU resources should be used/created, only deleted
     _resourcesLock.Lock();
@@ -456,7 +458,6 @@ void GPUDevice::preDispose()
     }
     _resources.Clear();
     _resourcesLock.Unlock();
-    Locker.Unlock();
 }
 
 void GPUDevice::DrawBegin()
diff --git a/Source/Engine/GraphicsDevice/DirectX/DX11/GPUBufferDX11.cpp b/Source/Engine/GraphicsDevice/DirectX/DX11/GPUBufferDX11.cpp
index ecf9e7bba..b82375cb4 100644
--- a/Source/Engine/GraphicsDevice/DirectX/DX11/GPUBufferDX11.cpp
+++ b/Source/Engine/GraphicsDevice/DirectX/DX11/GPUBufferDX11.cpp
@@ -21,6 +21,7 @@ void* GPUBufferDX11::Map(GPUResourceMapMode mode)
 {
     if (!IsInMainThread())
         _device->Locker.Lock();
+    ASSERT(!_mapped);
 
     D3D11_MAPPED_SUBRESOURCE map;
     map.pData = nullptr;
@@ -46,13 +47,18 @@ void* GPUBufferDX11::Map(GPUResourceMapMode mode)
     const HRESULT result = _device->GetIM()->Map(_resource, 0, mapType, mapFlags, &map);
     if (result != DXGI_ERROR_WAS_STILL_DRAWING)
         LOG_DIRECTX_RESULT(result);
+    _mapped = map.pData != nullptr;
     return map.pData;
 }
 
 void GPUBufferDX11::Unmap()
 {
-    _device->GetIM()->Unmap(_resource, 0);
-
+    if (_mapped)
+    {
+        _mapped = false;
+        _device->GetIM()->Unmap(_resource, 0);
+    }
+    
     if (!IsInMainThread())
         _device->Locker.Unlock();
 }
diff --git a/Source/Engine/GraphicsDevice/DirectX/DX11/GPUBufferDX11.h b/Source/Engine/GraphicsDevice/DirectX/DX11/GPUBufferDX11.h
index cdae2b846..a870c4de9 100644
--- a/Source/Engine/GraphicsDevice/DirectX/DX11/GPUBufferDX11.h
+++ b/Source/Engine/GraphicsDevice/DirectX/DX11/GPUBufferDX11.h
@@ -101,6 +101,7 @@ private:
 
     ID3D11Buffer* _resource = nullptr;
     GPUBufferViewDX11 _view;
+    bool _mapped = false;
 
 public:
 
diff --git a/Source/Engine/GraphicsDevice/DirectX/DX12/GPUBufferDX12.cpp b/Source/Engine/GraphicsDevice/DirectX/DX12/GPUBufferDX12.cpp
index 946c7f987..e13f30dc8 100644
--- a/Source/Engine/GraphicsDevice/DirectX/DX12/GPUBufferDX12.cpp
+++ b/Source/Engine/GraphicsDevice/DirectX/DX12/GPUBufferDX12.cpp
@@ -77,9 +77,10 @@ void GPUBufferDX12::Unmap()
         writtenRangePtr = nullptr;
         break;
     default:
-    CRASH;
+        return;
     }
     _resource->Unmap(0, writtenRangePtr);
+    _lastMapMode = (GPUResourceMapMode)255;
 }
 
 GPUResource* GPUBufferDX12::AsGPUResource() const
diff --git a/Source/Engine/GraphicsDevice/DirectX/DX12/GPUBufferDX12.h b/Source/Engine/GraphicsDevice/DirectX/DX12/GPUBufferDX12.h
index 0f3410b17..9c13dacd9 100644
--- a/Source/Engine/GraphicsDevice/DirectX/DX12/GPUBufferDX12.h
+++ b/Source/Engine/GraphicsDevice/DirectX/DX12/GPUBufferDX12.h
@@ -113,7 +113,7 @@ private:
 
     GPUBufferViewDX12 _view;
     GPUBufferDX12* _counter = nullptr;
-    GPUResourceMapMode _lastMapMode;
+    GPUResourceMapMode _lastMapMode = (GPUResourceMapMode)255;
 
 public:
 
diff --git a/Source/Engine/Renderer/GI/GlobalSurfaceAtlasPass.cpp b/Source/Engine/Renderer/GI/GlobalSurfaceAtlasPass.cpp
index e67ba36b2..c7dc2f990 100644
--- a/Source/Engine/Renderer/GI/GlobalSurfaceAtlasPass.cpp
+++ b/Source/Engine/Renderer/GI/GlobalSurfaceAtlasPass.cpp
@@ -684,13 +684,13 @@ bool GlobalSurfaceAtlasPass::Render(RenderContext& renderContext, GPUContext* co
                 if (data)
                 {
                     uint32 counter = data[surfaceAtlasData.CulledObjectsCounterIndex];
-                    _culledObjectsSizeBuffer->Unmap();
                     if (counter > 0)
                     {
                         objectsBufferCapacity = counter;
                         notReady = false;
                     }
                 }
+                _culledObjectsSizeBuffer->Unmap();
 
                 // Allow to be ready if the buffer was already used
                 if (notReady && surfaceAtlasData.CulledObjectsBuffer && surfaceAtlasData.CulledObjectsBuffer->IsAllocated())