1 files changed, 12 insertions, 1 deletions
diff --git a/Source/Core/VideoCommon/RenderBase.cpp b/Source/Core/VideoCommon/RenderBase.cpp
index f93d498fc6..0ff5b52902 100644
--- a/Source/Core/VideoCommon/RenderBase.cpp
+++ b/Source/Core/VideoCommon/RenderBase.cpp
@@ -187,7 +187,18 @@ void Renderer::ReinterpretPixelData(EFBReinterpretType convtype)
 
 u16 Renderer::BBoxRead(int index)
 {
-  return BBoxReadImpl(index);
+  u16 value = BBoxReadImpl(index);
+
+  // The GC/Wii GPU rasterizes in 2x2 pixel groups, so bounding box values will be rounded to the
+  // extents of these groups, rather than the exact pixel.
+  // This would have been handled in the pixel shader, but all attempts to do so did not work on
+  // OpenGL/NVIDIA, due to presumably mystical driver behavior with atomics.
+  if (index == 0 || index == 2)
+    value &= ~1;
+  else
+    value |= 1;
+
+  return value;
 }
 
 void Renderer::BBoxWrite(int index, u16 value)