From 0ae8fcced305a721d98b7caa1a1d30503a6705b5 Mon Sep 17 00:00:00 2001
From: Stenzek <stenzek@gmail.com>
Date: Mon, 25 Nov 2024 13:15:07 +1000
Subject: [PATCH] GPU/HW: Fix incorrect sampling at 1x with TC

---
 src/core/gpu_hw_shadergen.cpp   | 16 ++++++++++------
 src/core/shader_cache_version.h |  2 +-
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/core/gpu_hw_shadergen.cpp b/src/core/gpu_hw_shadergen.cpp
index 997cd86e9..e85738c17 100644
--- a/src/core/gpu_hw_shadergen.cpp
+++ b/src/core/gpu_hw_shadergen.cpp
@@ -880,13 +880,17 @@ float4 SampleFromVRAM(TEXPAGE_VALUE texpage, float2 coords)
 float4 SampleFromPageTexture(float2 coords)
 {
   // Cached textures.
-#if UPSCALED == 0
-  float2 fpart = coords - roundEven(coords);
-#else
-  float2 fpart = frac(coords);
-#endif
   uint2 icoord = ApplyTextureWindow(FloatToIntegerCoords(coords));
-  coords = (float2(icoord) + fpart) * (1.0f / 256.0f);
+#if UPSCALED
+  float2 fpart = frac(coords);
+  coords = (float2(icoord) + fpart);
+#else
+  // Drop fractional part.
+  coords = float2(icoord);
+#endif
+
+  // Normalize.
+  coords = coords * (1.0f / 256.0f);
   return SAMPLE_TEXTURE(samp0, coords);
 }
 
diff --git a/src/core/shader_cache_version.h b/src/core/shader_cache_version.h
index 9d926866a..89fec6d32 100644
--- a/src/core/shader_cache_version.h
+++ b/src/core/shader_cache_version.h
@@ -5,4 +5,4 @@
 
 #include "common/types.h"
 
-static constexpr u32 SHADER_CACHE_VERSION = 20;
+static constexpr u32 SHADER_CACHE_VERSION = 21;