From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 21 Apr 2014 07:36:17 +0000 (+0300)
Subject: Move sRGB formulas to color.h
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=f07dffb230b53efcf5e2706493b065f020077fdc;p=libs%2Fgl.git

Move sRGB formulas to color.h
---

diff --git a/source/color.h b/source/color.h
index c45751d0..e57689bf 100644
--- a/source/color.h
+++ b/source/color.h
@@ -1,9 +1,17 @@
 #ifndef MSP_GL_COLOR_H_
 #define MSP_GL_COLOR_H_
 
+#include <cmath>
+
 namespace Msp {
 namespace GL {
 
+inline float to_srgb(float c)
+{ return (c<=0.0031308f ? 12.92f*c : 1.055f*std::pow(c, 1/2.4f)-0.055f); }
+
+inline float to_linear(float c)
+{ return (c<=0.04045 ? c/12.92f : std::pow((c+0.055f)/1.055f, 2.4f)); }
+
 struct Color
 {
 	float r, g, b, a;
@@ -16,6 +24,9 @@ struct Color
 	Color operator+(const Color &c) const { return Color(r+c.r, g+c.g, b+c.b, 1-(1-a)*(1-c.a)); }
 	bool operator==(const Color &c) const { return (r==c.r && g==c.g && b==c.b && a==c.a); }
 	bool operator!=(const Color &c) const { return !operator==(c); }
+
+	Color to_srgb() const { return Color(GL::to_srgb(r), GL::to_srgb(g), GL::to_srgb(b), a); }
+	Color to_linear() const { return Color(GL::to_linear(r), GL::to_linear(g), GL::to_linear(b), a); }
 };
 
 } // namespace GL
diff --git a/source/colorcurve.cpp b/source/colorcurve.cpp
index 6351ea20..6b456dfe 100644
--- a/source/colorcurve.cpp
+++ b/source/colorcurve.cpp
@@ -1,4 +1,5 @@
 #include <cmath>
+#include "color.h"
 #include "colorcurve.h"
 #include "mesh.h"
 #include "shader.h"
@@ -88,7 +89,7 @@ void ColorCurve::set_srgb()
 	unsigned char curve_data[256];
 	curve_data[0] = 0;
 	for(unsigned i=1; i<256; ++i)
-		curve_data[i] = (1.055*pow(i/255.0f, 1/2.4f)-0.055)*255+0.5;
+		curve_data[i] = to_srgb(i/255.0f)*255+0.5f;
 	curve.image(0, LUMINANCE, UNSIGNED_BYTE, curve_data);
 }