From 1141f37cc4ae98441e0e75809a8757851c836408 Mon Sep 17 00:00:00 2001
From: "HuYingzhuo(hugo/hyzboy)" <hyzboy@gmail.com>
Date: Wed, 1 Nov 2023 19:13:54 +0800
Subject: [PATCH] used BT601 instead of BT709 in RGB2Lum

---
 inc/hgl/color/Lum.h | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/inc/hgl/color/Lum.h b/inc/hgl/color/Lum.h
index e021980..feac820 100644
--- a/inc/hgl/color/Lum.h
+++ b/inc/hgl/color/Lum.h
@@ -5,19 +5,24 @@
 
 namespace hgl
 {
-    template<typename T> constexpr T RGB2Lum(const T &r, const T &g, const T &b)
+    template<typename T> constexpr T RGB2Lum(const T &r,const T &g,const T &b)
     {
-        return 0.2126f*r+0.7152f*g+0.0722f*b;
-    }
-    
-    template<> constexpr uint8 RGB2Lum(const uint8 &r, const uint8 &g, const uint8 &b)
-    {
-        return (r*54+g*183+b*19)>>8;
+        return T(0.299f*r+0.587f*g+0.114f*b);
     }
 
+    template<> constexpr uint8 RGB2Lum(const uint8 &r,const uint8 &g,const uint8 &b)
+    {
+        return uint8((r*77+g*151+b*28)>>8);
+    }
+
+    template<typename T> constexpr T RGB2LumBT709(const T &r, const T &g, const T &b)
+    {
+        return T(0.2126f*r+0.7152f*g+0.0722f*b);
+    }
+    
     template<typename T> constexpr T RGB2LumBT2020(const T &r,const T &g,const T &b)
     {
-        return 0.2627f*r+0.6780f*g+0.0593f*b;
+        return T(0.2627f*r+0.6780f*g+0.0593f*b);
     }
 }//namespace hgl
 #endif//HGL_COLOR_LUM_INCLUDE