[dxvk] Add discardImage method

src/dxvk/dxvk_context.cpp

@@ -836,6 +836,24 @@ namespace dxvk {
   }
 
 
+  void DxvkContext::discardImage(
+    const Rc<DxvkImage>&          image,
+          VkImageSubresourceRange subresources) {
+    this->spillRenderPass();
+
+    if (m_barriers.isImageDirty(image, subresources, DxvkAccess::Write))
+      m_barriers.recordCommands(m_cmd);
+    
+    m_barriers.accessImage(image, subresources,
+      VK_IMAGE_LAYOUT_UNDEFINED, 0, 0,
+      image->info().layout,
+      image->info().stages,
+      image->info().access);
+    
+    m_cmd->trackResource(image);
+  }
+
+
   void DxvkContext::dispatch(
           uint32_t x,
           uint32_t y,

src/dxvk/dxvk_context.h

@@ -371,6 +371,19 @@ namespace dxvk {
     void discardBuffer(
       const Rc<DxvkBuffer>&       buffer);
     
+    /**
+     * \brief Discards image subresources
+     * 
+     * Discards the current contents of the image
+     * and performs a fast layout transition. This
+     * may improve performance in some cases.
+     * \param [in] image The image to discard
+     * \param [in] subresources Image subresources
+     */
+    void discardImage(
+      const Rc<DxvkImage>&          image,
+            VkImageSubresourceRange subresources);
+    
     /**
      * \brief Starts compute jobs
      *