Add GPUResourceUsage.Staging for both CPU read/write access

Source/Engine/Graphics/Enums.h

@@ -308,6 +308,17 @@ API_ENUM() enum class GPUResourceUsage
     /// - Any resources read or accessed randomly on host, e.g. CPU-side copy of vertex buffer used as source of transfer, but also used for collision detection.
     /// </remarks>
     StagingReadback = 3,
+
+    /// <summary>
+    /// A resource that supports both read and write from the CPU. 
+    /// This is likely to be the common choice for read-write buffers to transfer data between GPU compute buffers and CPU memory. 
+    /// It usually means CPU (system) memory.
+    /// </summary>
+    /// <remarks>
+    /// Usage:
+    /// - Staging memory to upload to GPU for compute and gather results back after processing.
+    /// </remarks>
+    Staging = 4,
 };
 
 /// <summary>

Source/Engine/Graphics/GPUBuffer.cpp

@@ -71,6 +71,15 @@ GPUBufferDescription GPUBufferDescription::ToStagingReadback() const
     return desc;
 }
 
+GPUBufferDescription GPUBufferDescription::ToStaging() const
+{
+    auto desc = *this;
+    desc.Usage = GPUResourceUsage::Staging;
+    desc.Flags = GPUBufferFlags::None;
+    desc.InitData = nullptr;
+    return desc;
+}
+
 bool GPUBufferDescription::Equals(const GPUBufferDescription& other) const
 {
     return Size == other.Size
@@ -123,6 +132,16 @@ GPUBuffer::GPUBuffer()
     _desc.Size = 0;
 }
 
+bool GPUBuffer::IsStaging() const
+{
+    return _desc.Usage == GPUResourceUsage::StagingReadback || _desc.Usage == GPUResourceUsage::StagingUpload || _desc.Usage == GPUResourceUsage::Staging;
+}
+
+bool GPUBuffer::IsDynamic() const
+{
+    return _desc.Usage == GPUResourceUsage::Dynamic;
+}
+
 bool GPUBuffer::Init(const GPUBufferDescription& desc)
 {
     ASSERT(Math::IsInRange<uint32>(desc.Size, 1, MAX_int32)
@@ -215,7 +234,7 @@ bool GPUBuffer::DownloadData(BytesContainer& result)
         LOG(Warning, "Cannot download GPU buffer data from an empty buffer.");
         return true;
     }
-    if (_desc.Usage == GPUResourceUsage::StagingReadback || _desc.Usage == GPUResourceUsage::Dynamic)
+    if (_desc.Usage == GPUResourceUsage::StagingReadback || _desc.Usage == GPUResourceUsage::Dynamic || _desc.Usage == GPUResourceUsage::Staging)
     {
         // Use faster path for staging resources
         return GetData(result);

Source/Engine/Graphics/GPUBuffer.h

@@ -86,20 +86,14 @@ public:
     }
 
     /// <summary>
-    /// Checks if buffer is a staging buffer (supports CPU readback).
+    /// Checks if buffer is a staging buffer (supports CPU access).
     /// </summary>
-    API_PROPERTY() FORCE_INLINE bool IsStaging() const
+    API_PROPERTY() bool IsStaging() const;
-    {
-        return _desc.Usage == GPUResourceUsage::StagingReadback || _desc.Usage == GPUResourceUsage::StagingUpload;
-    }
 
     /// <summary>
-    /// Checks if buffer is a staging buffer (supports CPU readback).
+    /// Checks if buffer is a dynamic buffer.
     /// </summary>
-    API_PROPERTY() FORCE_INLINE bool IsDynamic() const
+    API_PROPERTY() bool IsDynamic() const;
-    {
-        return _desc.Usage == GPUResourceUsage::Dynamic;
-    }
 
     /// <summary>
     /// Gets a value indicating whether this buffer is a shader resource.
@@ -173,7 +167,7 @@ public:
     Task* DownloadDataAsync(BytesContainer& result);
 
     /// <summary>
-    /// Gets the buffer data via map/memcpy/unmap sequence. Always supported for dynamic and staging readback buffers (other types support depends on graphics backend implementation).
+    /// Gets the buffer data via map/memcpy/unmap sequence. Always supported for dynamic and staging buffers (other types support depends on graphics backend implementation).
     /// </summary>
     /// <param name="output">The output data container.</param>
     /// <returns>True if failed, otherwise false.</returns>

Source/Engine/Graphics/GPUBufferDescription.cs

@@ -271,7 +271,7 @@ namespace FlaxEngine
         }
 
         /// <summary>
-        /// Gets the staging upload description for this instance.
+        /// Gets the staging upload (CPU write) description for this instance.
         /// </summary>
         /// <returns>A staging buffer description</returns>
         public GPUBufferDescription ToStagingUpload()
@@ -284,7 +284,7 @@ namespace FlaxEngine
         }
 
         /// <summary>
-        /// Gets the staging readback description for this instance.
+        /// Gets the staging readback (CPU read) description for this instance.
         /// </summary>
         /// <returns>A staging buffer description</returns>
         public GPUBufferDescription ToStagingReadback()
@@ -296,6 +296,19 @@ namespace FlaxEngine
             return desc;
         }
 
+        /// <summary>
+        /// Gets the staging (CPU read/write) description for this instance.
+        /// </summary>
+        /// <returns>A staging buffer description</returns>
+        public GPUBufferDescription ToStaging()
+        {
+            var desc = this;
+            desc.Usage = GPUResourceUsage.Staging;
+            desc.Flags = GPUBufferFlags.None;
+            desc.InitData = IntPtr.Zero;
+            return desc;
+        }
+
         /// <inheritdoc />
         public bool Equals(GPUBufferDescription other)
         {

Source/Engine/Graphics/GPUBufferDescription.h

@@ -335,6 +335,7 @@ public:
     void Clear();
     GPUBufferDescription ToStagingUpload() const;
     GPUBufferDescription ToStagingReadback() const;
+    GPUBufferDescription ToStaging() const;
     bool Equals(const GPUBufferDescription& other) const;
     String ToString() const;
 

Source/Engine/Graphics/Textures/GPUTexture.cpp

@@ -142,6 +142,14 @@ GPUTextureDescription GPUTextureDescription::ToStagingReadback() const
     return copy;
 }
 
+GPUTextureDescription GPUTextureDescription::ToStaging() const
+{
+    auto copy = *this;
+    copy.Flags = GPUTextureFlags::None;
+    copy.Usage = GPUResourceUsage::Staging;
+    return copy;
+}
+
 bool GPUTextureDescription::Equals(const GPUTextureDescription& other) const
 {
     return Dimensions == other.Dimensions
@@ -208,6 +216,11 @@ GPUTexture::GPUTexture()
     _desc.Clear();
 }
 
+bool GPUTexture::IsStaging() const
+{
+    return _desc.Usage == GPUResourceUsage::StagingUpload || _desc.Usage == GPUResourceUsage::StagingReadback || _desc.Usage == GPUResourceUsage::Staging;
+}
+
 Float2 GPUTexture::Size() const
 {
     return Float2(static_cast<float>(_desc.Width), static_cast<float>(_desc.Height));

Source/Engine/Graphics/Textures/GPUTexture.h

@@ -294,10 +294,7 @@ public:
     /// <summary>
     /// Checks if texture is a staging buffer (supports direct CPU access).
     /// </summary>
-    FORCE_INLINE bool IsStaging() const
+    bool IsStaging() const;
-    {
-        return _desc.Usage == GPUResourceUsage::StagingUpload || _desc.Usage == GPUResourceUsage::StagingReadback;
-    }
 
     /// <summary>
     /// Gets a boolean indicating whether this <see cref="GPUTexture"/> is a using a block compress format (BC1, BC2, BC3, BC4, BC5, BC6H, BC7, etc.).

Source/Engine/Graphics/Textures/GPUTextureDescription.cs

@@ -300,7 +300,7 @@ namespace FlaxEngine
         }
 
         /// <summary>
-        /// Gets the staging description for this instance.
+        /// Gets the staging upload (CPU write) description for this instance.
         /// </summary>
         /// <returns>A staging texture description</returns>
         public GPUTextureDescription ToStagingUpload()
@@ -312,7 +312,7 @@ namespace FlaxEngine
         }
 
         /// <summary>
-        /// Gets the staging description for this instance.
+        /// Gets the staging readback (CPU read) description for this instance.
         /// </summary>
         /// <returns>A staging texture description</returns>
         public GPUTextureDescription ToStagingReadback()
@@ -323,6 +323,18 @@ namespace FlaxEngine
             return desc;
         }
 
+        /// <summary>
+        /// Gets the staging (CPU read/write) description for this instance.
+        /// </summary>
+        /// <returns>A staging texture description</returns>
+        public GPUTextureDescription ToStaging()
+        {
+            var desc = this;
+            desc.Flags = GPUTextureFlags.None;
+            desc.Usage = GPUResourceUsage.Staging;
+            return desc;
+        }
+
         /// <inheritdoc />
         public override string ToString()
         {

Source/Engine/Graphics/Textures/GPUTextureDescription.h

@@ -397,6 +397,7 @@ public:
     void Clear();
     GPUTextureDescription ToStagingUpload() const;
     GPUTextureDescription ToStagingReadback() const;
+    GPUTextureDescription ToStaging() const;
     bool Equals(const GPUTextureDescription& other) const;
     String ToString() const;
 

Source/Engine/GraphicsDevice/DirectX/DX12/GPUBufferDX12.cpp

@@ -120,6 +120,7 @@ bool GPUBufferDX12::OnInit()
     switch (_desc.Usage)
     {
     case GPUResourceUsage::StagingUpload:
+    case GPUResourceUsage::Staging:
         heapProperties.Type = D3D12_HEAP_TYPE_UPLOAD;
         break;
     case GPUResourceUsage::StagingReadback:
@@ -152,7 +153,7 @@ bool GPUBufferDX12::OnInit()
         // But if we are doing it during update or from the other thread we have to register resource data upload job.
         // In both cases options.InitData data have to exist for a few next frames.
 
-        if (_desc.Usage == GPUResourceUsage::StagingUpload)
+        if (_desc.Usage == GPUResourceUsage::StagingUpload || _desc.Usage == GPUResourceUsage::Staging)
         {
             // Modify staging resource data now
             SetData(_desc.InitData, _desc.Size);

Source/Engine/GraphicsDevice/DirectX/RenderToolsDX.h

@@ -28,6 +28,7 @@ namespace RenderToolsDX
         {
         case GPUResourceUsage::Dynamic:
             return D3D11_USAGE_DYNAMIC;
+        case GPUResourceUsage::Staging:
         case GPUResourceUsage::StagingUpload:
         case GPUResourceUsage::StagingReadback:
             return D3D11_USAGE_STAGING;
@@ -47,6 +48,8 @@ namespace RenderToolsDX
         {
         case GPUResourceUsage::Dynamic:
             return D3D11_CPU_ACCESS_WRITE;
+        case GPUResourceUsage::Staging:
+            return D3D11_CPU_ACCESS_READ | D3D11_CPU_ACCESS_WRITE;
         case GPUResourceUsage::StagingReadback:
             return D3D11_CPU_ACCESS_READ;
         case GPUResourceUsage::StagingUpload:

Source/Engine/GraphicsDevice/Vulkan/GPUBufferVulkan.cpp

@@ -128,6 +128,9 @@ bool GPUBufferVulkan::OnInit()
     case GPUResourceUsage::StagingReadback:
         allocInfo.usage = VMA_MEMORY_USAGE_GPU_TO_CPU;
         break;
+    case GPUResourceUsage::Staging:
+        allocInfo.usage = VMA_MEMORY_USAGE_CPU_COPY;
+        break;
     default:
         allocInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY;
     }