From 2664237026f17e5f0716c41a3fe08c3befc8c094 Mon Sep 17 00:00:00 2001
From: Jennifer Taylor <dragonminded@dragonminded.com>
Date: Sun, 24 Oct 2021 15:51:08 +0000
Subject: [PATCH] Merge overlay blend mode fix from ARCHVILE.

---
 bemani/format/afp/blend/blend.py         | 8 +++-----
 bemani/format/afp/blend/blendcppimpl.cxx | 8 +++-----
 2 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/bemani/format/afp/blend/blend.py b/bemani/format/afp/blend/blend.py
index 8465e57..f5990e9 100644
--- a/bemani/format/afp/blend/blend.py
+++ b/bemani/format/afp/blend/blend.py
@@ -131,12 +131,10 @@ def blend_overlay(
     # jubeat uses the alternative formula Src * Dst + Dst * (1 - As).
 
     # Calculate final color blending.
-    src_alpha = src[3] / 255.0
-    src_remainder = 1.0 - src_alpha
     return (
-        clamp((255 * (2.0 * (dest[0] / 255.0) * (src[0] / 255.0) * src_alpha)) + (dest[0] * src_remainder)),
-        clamp((255 * (2.0 * (dest[1] / 255.0) * (src[1] / 255.0) * src_alpha)) + (dest[1] * src_remainder)),
-        clamp((255 * (2.0 * (dest[2] / 255.0) * (src[2] / 255.0) * src_alpha)) + (dest[2] * src_remainder)),
+        clamp((255 * (2.0 * (dest[0] / 255.0) * (src[0] / 255.0)))),
+        clamp((255 * (2.0 * (dest[1] / 255.0) * (src[1] / 255.0)))),
+        clamp((255 * (2.0 * (dest[2] / 255.0) * (src[2] / 255.0)))),
         dest[3],
     )
 
diff --git a/bemani/format/afp/blend/blendcppimpl.cxx b/bemani/format/afp/blend/blendcppimpl.cxx
index 8d6a8fe..8212c40 100644
--- a/bemani/format/afp/blend/blendcppimpl.cxx
+++ b/bemani/format/afp/blend/blendcppimpl.cxx
@@ -204,12 +204,10 @@ extern "C"
         // jubeat uses the alternative formula Src * Dst + Dst * (1 - As).
 
         // Calculate final color blending.
-        double src_alpha = src.a / 255.0;
-        double src_remainder = 1.0 - src_alpha;
         return (intcolor_t){
-            clamp((255 * (2.0 * (dest.r / 255.0) * (src.r / 255.0) * src_alpha)) + (dest.r * src_remainder)),
-            clamp((255 * (2.0 * (dest.g / 255.0) * (src.g / 255.0) * src_alpha)) + (dest.g * src_remainder)),
-            clamp((255 * (2.0 * (dest.b / 255.0) * (src.b / 255.0) * src_alpha)) + (dest.b * src_remainder)),
+            clamp((255 * (2.0 * (dest.r / 255.0) * (src.r / 255.0)))),
+            clamp((255 * (2.0 * (dest.g / 255.0) * (src.g / 255.0)))),
+            clamp((255 * (2.0 * (dest.b / 255.0) * (src.b / 255.0)))),
             dest.a,
         };
     }