From 894d9606d5c5a1b8dfff966fed8e0f7c4a9b82c0 Mon Sep 17 00:00:00 2001
From: Philip Rebohle <philip.rebohle@tu-dortmund.de>
Date: Sat, 29 Sep 2018 08:13:52 +0200
Subject: [PATCH] [dxgi] Add option to force-enable MAILBOX present mode

Provides Enhanced Sync-like functionality (#678).
---
 src/dxgi/dxgi_options.cpp   |  1 +
 src/dxgi/dxgi_options.h     | 11 +++++++++++
 src/dxgi/dxgi_presenter.cpp |  5 ++++-
 src/dxgi/dxgi_presenter.h   |  1 +
 4 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/dxgi/dxgi_options.cpp b/src/dxgi/dxgi_options.cpp
index c1ebbca51..22e1173c3 100644
--- a/src/dxgi/dxgi_options.cpp
+++ b/src/dxgi/dxgi_options.cpp
@@ -41,6 +41,7 @@ namespace dxvk {
 
     this->numBackBuffers = config.getOption<int32_t>("dxgi.numBackBuffers", 0);
     this->syncInterval   = config.getOption<int32_t>("dxgi.syncInterval", -1);
+    this->syncMode       = DxgiSyncMode(config.getOption<int32_t>("dxgi.syncMode", 0));
 
     this->d3d10Enable = config.getOption<bool>("d3d10.enable", true);
   }
diff --git a/src/dxgi/dxgi_options.h b/src/dxgi/dxgi_options.h
index d7a32e6a6..e661ad26a 100644
--- a/src/dxgi/dxgi_options.h
+++ b/src/dxgi/dxgi_options.h
@@ -7,6 +7,14 @@
 #include "dxgi_include.h"
 
 namespace dxvk {
+
+  /**
+   * \brief Sync mode
+   */
+  enum class DxgiSyncMode : int32_t {
+    Default   = 0,
+    Mailbox   = 1,
+  };
   
   /**
    * \brief DXGI options
@@ -46,6 +54,9 @@ namespace dxvk {
     /// passed to IDXGISwapChain::Present.
     int32_t syncInterval;
 
+    /// Vsync mode
+    DxgiSyncMode syncMode;
+
     /// Enables D3D10 support
     bool d3d10Enable;
   };
diff --git a/src/dxgi/dxgi_presenter.cpp b/src/dxgi/dxgi_presenter.cpp
index c1a8db854..be6f2502c 100644
--- a/src/dxgi/dxgi_presenter.cpp
+++ b/src/dxgi/dxgi_presenter.cpp
@@ -13,7 +13,8 @@ namespace dxvk {
           HWND                    window)
   : m_window  (window),
     m_device  (device),
-    m_context (device->createContext()) {
+    m_context (device->createContext()),
+    m_syncMode(pOptions->syncMode) {
     
     // Some games don't work with deferred surface creation,
     // so we should default to initializing it immediately.
@@ -367,6 +368,8 @@ namespace dxvk {
     size_t n = 0;
     
     if (Vsync) {
+      if (m_syncMode == DxgiSyncMode::Mailbox)
+        modes[n++] = VK_PRESENT_MODE_MAILBOX_KHR;
       modes[n++] = VK_PRESENT_MODE_FIFO_KHR;
     } else {
       modes[n++] = VK_PRESENT_MODE_IMMEDIATE_KHR;
diff --git a/src/dxgi/dxgi_presenter.h b/src/dxgi/dxgi_presenter.h
index ca2918f59..25b12be6a 100644
--- a/src/dxgi/dxgi_presenter.h
+++ b/src/dxgi/dxgi_presenter.h
@@ -163,6 +163,7 @@ namespace dxvk {
     DxvkLogicOpState        m_loState;
     DxvkBlendMode           m_blendMode;
     DxvkSwapchainProperties m_options;
+    DxgiSyncMode            m_syncMode;
     
     VkSurfaceFormatKHR PickSurfaceFormat(DXGI_FORMAT Fmt) const;