[dxgi] Support SyncInterval values > 1

Required for Eve Online and the Unity Blacksmith demo.

src/dxgi/dxgi_presenter.cpp

@@ -143,7 +143,7 @@ namespace dxvk {
   }
   
   
-  void DxgiVkPresenter::PresentImage() {
+  void DxgiVkPresenter::PresentImage(UINT SyncInterval) {
     if (m_hud != nullptr) {
       m_hud->render({
         m_options.preferredBufferSize.width,
@@ -151,20 +151,26 @@ namespace dxvk {
       });
     }
     
+    // Check whether the back buffer size is the same
+    // as the window size, in which case we should use
+    // VK_FILTER_NEAREST to avoid blurry output
     const bool fitSize =
         m_backBuffer->info().extent.width  == m_options.preferredBufferSize.width
      && m_backBuffer->info().extent.height == m_options.preferredBufferSize.height;
     
+    for (uint32_t i = 0; i < SyncInterval || i < 1; i++) {
       m_context->beginRecording(
         m_device->createCommandList());
       
+      // Resolve back buffer if it is multisampled. We
+      // only have to do it only for the first frame.
+      if (m_backBufferResolve != nullptr && i == 0) {
         VkImageSubresourceLayers resolveSubresources;
         resolveSubresources.aspectMask      = VK_IMAGE_ASPECT_COLOR_BIT;
         resolveSubresources.mipLevel        = 0;
         resolveSubresources.baseArrayLayer  = 0;
         resolveSubresources.layerCount      = 1;
         
-    if (m_backBufferResolve != nullptr) {
         m_context->resolveImage(
           m_backBufferResolve, resolveSubresources,
           m_backBuffer,        resolveSubresources,
@@ -223,6 +229,7 @@ namespace dxvk {
       m_swapchain->present(
         swapSemas.presentSync);
     }
+  }
   
   
   void DxgiVkPresenter::UpdateBackBuffer(const Rc<DxvkImage>& Image) {

src/dxgi/dxgi_presenter.h

@@ -82,8 +82,9 @@ namespace dxvk {
     
     /**
      * \brief Renders back buffer to the screen
+     * \param [in] SyncInterval Vsync interval
      */
-    void PresentImage();
+    void PresentImage(UINT SyncInterval);
     
     /**
      * \brief Sets new back buffer

src/dxgi/dxgi_swapchain.cpp

@@ -286,6 +286,12 @@ namespace dxvk {
     if (Flags & DXGI_PRESENT_TEST)
       return S_OK;
     
+    // Higher values are not allowed according to the Microsoft documentation:
+    // 
+    //   "1 through 4 - Synchronize presentation after the nth vertical blank."
+    //   https://msdn.microsoft.com/en-us/library/windows/desktop/bb174576(v=vs.85).aspx
+    SyncInterval = std::min<UINT>(SyncInterval, 4);
+    
     try {
       // If in fullscreen mode, apply any updated gamma curve
       // if it has been changed since the last present call.
@@ -311,7 +317,7 @@ namespace dxvk {
         : VK_PRESENT_MODE_FIFO_KHR;
       
       m_presenter->RecreateSwapchain(m_desc.Format, presentMode, GetWindowSize());
-      m_presenter->PresentImage();
+      m_presenter->PresentImage(SyncInterval);
       return S_OK;
     } catch (const DxvkError& err) {
       Logger::err(err.message());