From 70626628f99cacfb641ac52ce4de0b61ecef914e Mon Sep 17 00:00:00 2001
From: Joshua Ashton <joshua@froggi.es>
Date: Tue, 27 Jun 2023 09:48:47 +0100
Subject: [PATCH] rendervulkan: Pick right first partial composite image

---
 src/rendervulkan.cpp | 18 +++++++++++++++++-
 src/steamcompmgr.cpp |  2 +-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/rendervulkan.cpp b/src/rendervulkan.cpp
index 5bdd603..7021e08 100644
--- a/src/rendervulkan.cpp
+++ b/src/rendervulkan.cpp
@@ -42,6 +42,7 @@
 #include "shaders/ffx_fsr1.h"
 #include "shaders/descriptor_set_constants.h"
 
+extern bool g_bWasPartialComposite;
 
 static constexpr mat3x4 g_rgb2yuv_srgb_to_bt601_limited = {{
   { 0.257f, 0.504f, 0.098f, 0.0625f },
@@ -3587,9 +3588,24 @@ bool vulkan_composite( const struct FrameInfo_t *frameInfo, std::shared_ptr<CVul
 
 	if ( partial )
 	{
-		g_output.nOutPresentImagePartial = g_output.nOutImagePartial;
+		if ( !g_bWasPartialComposite )
+		{
+			g_output.nOutPresentImagePartial = g_output.nOutImage;
+			g_output.nOutImagePartial        = g_output.nOutImage;
+		}
+		else
+		{
+			g_output.nOutPresentImagePartial = g_output.nOutImagePartial;
+		}
 		g_output.nOutImagePartial = ( g_output.nOutImagePartial + 1 ) % 3;
 	}
+	else
+	{
+		if (g_bWasPartialComposite)
+		{
+			g_output.nOutImage = ( g_output.nOutImagePartial + 1 ) % 3;
+		}
+	}
 
 	auto compositeImage = partial ? g_output.outputImagesPartialOverlay[ g_output.nOutImagePartial ] : g_output.outputImages[ g_output.nOutImage ];
 
diff --git a/src/steamcompmgr.cpp b/src/steamcompmgr.cpp
index b81a9a3..fa59bdd 100644
--- a/src/steamcompmgr.cpp
+++ b/src/steamcompmgr.cpp
@@ -101,6 +101,7 @@
 
 static LogScope xwm_log("xwm");
 
+bool g_bWasPartialComposite = false;
 
 ///
 // Color Mgmt
@@ -2433,7 +2434,6 @@ paint_all(bool async)
 	}
 	bNeedsFullComposite |= !!(g_uCompositeDebug & CompositeDebugFlag::Heatmap);
 
-	static bool g_bWasPartialComposite = false;
 	static int g_nLastSingleOverlayZPos = 0;
 
 	if ( !bNeedsFullComposite && !bWantsPartialComposite )