Added swap chain usage flags

3 files changed, 45 insertions, 8 deletions

diff --git a/Graphics/GraphicsEngine/interface/GraphicsTypes.h b/Graphics/GraphicsEngine/interface/GraphicsTypes.h
index 746f6a67..d13a06f5 100644
--- a/Graphics/GraphicsEngine/interface/GraphicsTypes.h
+++ b/Graphics/GraphicsEngine/interface/GraphicsTypes.h
@@ -1172,6 +1172,23 @@ namespace Diligent
         SCANLINE_ORDER ScanlineOrder    = SCANLINE_ORDER_UNSPECIFIED;
     };
 
+    /// Defines allowed swap chain usage flags
+    enum SWAP_CHAIN_USAGE_FLAGS : Uint32
+    {
+        /// No allowed usage
+        SWAP_CHAIN_USAGE_NONE           = 0x00L,
+        
+        /// Swap chain can be used as render target ouput
+        SWAP_CHAIN_USAGE_RENDER_TARGET  = 0x01L,
+
+        /// Swap chain images can be used as shader inputs
+        SWAP_CHAIN_USAGE_SHADER_INPUT   = 0x02L,
+
+        /// Swap chain images can be used as source of copy operation
+        SWAP_CHAIN_USAGE_COPY_SOURCE    = 0x04L
+    };
+    DEFINE_FLAG_ENUM_OPERATORS(SWAP_CHAIN_USAGE_FLAGS)
+
     /// Swap chain description
     struct SwapChainDesc
     {
@@ -1187,6 +1204,9 @@ namespace Diligent
         /// Depth buffer format. Default value is Diligent::TEX_FORMAT_D32_FLOAT
         TEXTURE_FORMAT DepthBufferFormat    = TEX_FORMAT_D32_FLOAT;
 
+        /// Swap chain usage flags. Default value is Diligent::SWAP_CHAIN_USAGE_RENDER_TARGET
+        SWAP_CHAIN_USAGE_FLAGS Usage        = SWAP_CHAIN_USAGE_RENDER_TARGET;
+
         /// Sample count. Default value is 1
         Uint32 SamplesCount                 = 1;
 
diff --git a/Graphics/GraphicsEngineD3DBase/include/SwapChainD3DBase.h b/Graphics/GraphicsEngineD3DBase/include/SwapChainD3DBase.h
index db8a409c..c4cfa0b9 100644
--- a/Graphics/GraphicsEngineD3DBase/include/SwapChainD3DBase.h
+++ b/Graphics/GraphicsEngineD3DBase/include/SwapChainD3DBase.h
@@ -87,7 +87,7 @@ namespace Diligent
             auto DXGIColorBuffFmt = TexFormatToDXGI_Format(m_SwapChainDesc.ColorBufferFormat);
 
             DXGI_SWAP_CHAIN_DESC1 swapChainDesc = {};
-            swapChainDesc.Width = m_SwapChainDesc.Width;
+            swapChainDesc.Width  = m_SwapChainDesc.Width;
             swapChainDesc.Height = m_SwapChainDesc.Height;
             //  Flip model swapchains (DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL and DXGI_SWAP_EFFECT_FLIP_DISCARD) only support the following Formats: 
             //  - DXGI_FORMAT_R16G16B16A16_FLOAT 
@@ -96,13 +96,22 @@ namespace Diligent
             //  - DXGI_FORMAT_R10G10B10A2_UNORM
             // If RGBA8_UNORM_SRGB swap chain is required, we will create RGBA8_UNORM swap chain, but
             // create RGBA8_UNORM_SRGB render target view
-            swapChainDesc.Format = DXGIColorBuffFmt == DXGI_FORMAT_R8G8B8A8_UNORM_SRGB ? DXGI_FORMAT_R8G8B8A8_UNORM : DXGIColorBuffFmt;
-            swapChainDesc.Stereo = FALSE;
-            swapChainDesc.SampleDesc.Count = 1;
+            swapChainDesc.Format             = DXGIColorBuffFmt == DXGI_FORMAT_R8G8B8A8_UNORM_SRGB ? DXGI_FORMAT_R8G8B8A8_UNORM : DXGIColorBuffFmt;
+            swapChainDesc.Stereo             = FALSE;
+            swapChainDesc.SampleDesc.Count   = 1;
             swapChainDesc.SampleDesc.Quality = 0;
-            swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
-            swapChainDesc.BufferCount = m_SwapChainDesc.BufferCount;
-            swapChainDesc.Scaling = DXGI_SCALING_NONE;
+            
+            DEV_CHECK_ERR(m_SwapChainDesc.Usage != 0, "No swap chain usage flags defined");
+            swapChainDesc.BufferUsage = 0;
+            if (m_SwapChainDesc.Usage & SWAP_CHAIN_USAGE_RENDER_TARGET)
+                swapChainDesc.BufferUsage |= DXGI_USAGE_RENDER_TARGET_OUTPUT;
+            if (m_SwapChainDesc.Usage & SWAP_CHAIN_USAGE_SHADER_INPUT)
+                swapChainDesc.BufferUsage |= DXGI_USAGE_SHADER_INPUT;
+            //if (m_SwapChainDesc.Usage & SWAP_CHAIN_USAGE_COPY_SOURCE)
+            //    ;
+
+            swapChainDesc.BufferCount        = m_SwapChainDesc.BufferCount;
+            swapChainDesc.Scaling            = DXGI_SCALING_NONE;
 
             // DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL is the flip presentation model, where the contents of the back 
             // buffer is preserved after the call to Present. This flag cannot be used with multisampling.
diff --git a/Graphics/GraphicsEngineVulkan/src/SwapChainVkImpl.cpp b/Graphics/GraphicsEngineVulkan/src/SwapChainVkImpl.cpp
index befa0db4..7277a744 100644
--- a/Graphics/GraphicsEngineVulkan/src/SwapChainVkImpl.cpp
+++ b/Graphics/GraphicsEngineVulkan/src/SwapChainVkImpl.cpp
@@ -271,7 +271,15 @@ void SwapChainVkImpl::CreateVulkanSwapChain()
     swapchain_ci.oldSwapchain       = oldSwapchain;
     swapchain_ci.clipped            = VK_TRUE;
     swapchain_ci.imageColorSpace    = ColorSpace;
-    swapchain_ci.imageUsage         = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
+    
+    DEV_CHECK_ERR(m_SwapChainDesc.Usage != 0, "No swap chain usage flags defined");
+    if (m_SwapChainDesc.Usage & SWAP_CHAIN_USAGE_RENDER_TARGET)
+        swapchain_ci.imageUsage |= VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
+    if (m_SwapChainDesc.Usage & SWAP_CHAIN_USAGE_SHADER_INPUT)
+        swapchain_ci.imageUsage |= VK_IMAGE_USAGE_SAMPLED_BIT;
+    if (m_SwapChainDesc.Usage & SWAP_CHAIN_USAGE_COPY_SOURCE)
+        swapchain_ci.imageUsage |= VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
+
     // vkCmdClearColorImage() command requires the image to use VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL layout
     // that requires  VK_IMAGE_USAGE_TRANSFER_DST_BIT to be set
     swapchain_ci.imageSharingMode = VK_SHARING_MODE_EXCLUSIVE;