From b30d56ccc0a03c41c758afcd47f5d19fa34b0a98 Mon Sep 17 00:00:00 2001
From: Jonathan Hamilton <jtrhamilton@gmail.com>
Date: Thu, 17 May 2018 09:39:39 -0700
Subject: [PATCH] Texture AverageDiff: Do more in int space and avoid excessive
 float conversion

Multiplying 2x 8bit values is guaranteed to fit in 16bits, 4 channels then in
18bits, which means an 'int' shouild be sufficient to avoid overflows
---
 Source/Core/VideoCommon/TextureCacheBase.cpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/Source/Core/VideoCommon/TextureCacheBase.cpp b/Source/Core/VideoCommon/TextureCacheBase.cpp
index 1b385dcbfe..c84bb6ec38 100644
--- a/Source/Core/VideoCommon/TextureCacheBase.cpp
+++ b/Source/Core/VideoCommon/TextureCacheBase.cpp
@@ -608,13 +608,14 @@ private:
         const auto* row2 = ptr2;
         for (u32 j = 0; j < shape.width; ++j, row1 += 4, row2 += 4)
         {
+          int pixel_diff = 0;
           for (int channel = 0; channel < 4; channel++)
           {
-            const float diff =
-                std::abs(static_cast<float>(row1[channel]) - static_cast<float>(row2[channel]));
-            const float diff_squared = diff * diff;
-            average_diff += diff_squared;
+            const int diff = static_cast<int>(row1[channel]) - static_cast<int>(row2[channel]);
+            const int diff_squared = diff * diff;
+            pixel_diff += diff_squared;
           }
+          average_diff += pixel_diff;
         }
         ptr1 += shape.row_length;
         ptr2 += shape.row_length;