From 4897cf7ef2070120310c28a1a672b427d745dad8 Mon Sep 17 00:00:00 2001
From: Skyth <19259897+blueskythlikesclouds@users.noreply.github.com>
Date: Sat, 15 Mar 2025 21:41:52 +0300
Subject: [PATCH] Apply half pixel offset in the vertex shader.

---
 XenosRecomp/shader_common.h       | 6 ++++--
 XenosRecomp/shader_recompiler.cpp | 4 ++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/XenosRecomp/shader_common.h b/XenosRecomp/shader_common.h
index 7ce0d8a..c9ef6ff 100644
--- a/XenosRecomp/shader_common.h
+++ b/XenosRecomp/shader_common.h
@@ -25,7 +25,8 @@ struct PushConstants
 
 #define g_Booleans                 vk::RawBufferLoad<uint>(g_PushConstants.SharedConstants + 256)
 #define g_SwappedTexcoords         vk::RawBufferLoad<uint>(g_PushConstants.SharedConstants + 260)
-#define g_AlphaThreshold           vk::RawBufferLoad<float>(g_PushConstants.SharedConstants + 264)
+#define g_HalfPixelOffset          vk::RawBufferLoad<float2>(g_PushConstants.SharedConstants + 264)
+#define g_AlphaThreshold           vk::RawBufferLoad<float>(g_PushConstants.SharedConstants + 272)
 
 [[vk::constant_id(0)]] const uint g_SpecConstants = 0;
 
@@ -36,7 +37,8 @@ struct PushConstants
 #define DEFINE_SHARED_CONSTANTS() \
     uint g_Booleans : packoffset(c16.x); \
     uint g_SwappedTexcoords : packoffset(c16.y); \
-    float g_AlphaThreshold : packoffset(c16.z) \
+    float2 g_HalfPixelOffset : packoffset(c16.z); \
+    float g_AlphaThreshold : packoffset(c17.x);
 
 uint g_SpecConstants();
 
diff --git a/XenosRecomp/shader_recompiler.cpp b/XenosRecomp/shader_recompiler.cpp
index e59879f..c73483c 100644
--- a/XenosRecomp/shader_recompiler.cpp
+++ b/XenosRecomp/shader_recompiler.cpp
@@ -1782,6 +1782,10 @@ void ShaderRecompiler::recompile(const uint8_t* shaderData, const std::string_vi
                     indent();
                     out += '}';
                 }
+                else
+                {
+                    out += "\toPos.xy += g_HalfPixelOffset * oPos.w;\n";
+                }
 
                 if (simpleControlFlow)
                 {