From 804ffb00e29a252a4ac9ba1c261a2b97c111fe77 Mon Sep 17 00:00:00 2001
From: baldurk <baldurk@baldurk.org>
Date: Fri, 27 Jan 2017 11:00:22 +0000
Subject: [PATCH] Try to merge subresource states for resources that were split
 apart

* When a barrier applies to only one subresource out of an image, it's
  split into individual subresource tracking. There's nothing to merge
  it back together again, so it remains split even if the subresources
  go back to all being in the same state again. Simply checking when
  fetching the frame-initial states if we can merge can be a big win.
---
 renderdoc/driver/vulkan/vk_manager.cpp | 34 ++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/renderdoc/driver/vulkan/vk_manager.cpp b/renderdoc/driver/vulkan/vk_manager.cpp
index 985b7974e..910a17e1f 100644
--- a/renderdoc/driver/vulkan/vk_manager.cpp
+++ b/renderdoc/driver/vulkan/vk_manager.cpp
@@ -325,6 +325,40 @@ void VulkanResourceManager::SerialiseImageStates(map<ResourceId, ImageLayouts> &
     else
       ++it;
   }
+
+  // try to merge images that have been split up by subresource but are now all in the same state
+  // again.
+  for(auto it = states.begin(); it != states.end(); ++it)
+  {
+    ImageLayouts &layouts = it->second;
+
+    if(layouts.subresourceStates.size() > 1 &&
+       layouts.subresourceStates.size() == layouts.layerCount * layouts.levelCount)
+    {
+      VkImageLayout layout = layouts.subresourceStates[0].newLayout;
+
+      bool allIdentical = true;
+
+      for(size_t i = 0; i < layouts.subresourceStates.size(); i++)
+      {
+        if(layouts.subresourceStates[i].newLayout != layout)
+        {
+          allIdentical = false;
+          break;
+        }
+      }
+
+      if(allIdentical)
+      {
+        layouts.subresourceStates.erase(layouts.subresourceStates.begin() + 1,
+                                        layouts.subresourceStates.end());
+        layouts.subresourceStates[0].subresourceRange.baseArrayLayer = 0;
+        layouts.subresourceStates[0].subresourceRange.baseMipLevel = 0;
+        layouts.subresourceStates[0].subresourceRange.layerCount = layouts.layerCount;
+        layouts.subresourceStates[0].subresourceRange.levelCount = layouts.levelCount;
+      }
+    }
+  }
 }
 
 void VulkanResourceManager::MarkSparseMapReferenced(SparseMapping *sparse)