1 files changed, 32 insertions, 0 deletions
diff --git a/res/effectlib/luminance.glsllib b/res/effectlib/luminance.glsllib
new file mode 100644
index 0000000..bb7c08f
--- /dev/null
+++ b/res/effectlib/luminance.glsllib
@@ -0,0 +1,32 @@
+#ifndef LUMINANCE_GLSLLIB
+#define LUMINANCE_GLSLLIB
+
+// Luma coefficients according to ITU-R Recommendation BT.709 (http://en.wikipedia.org/wiki/Rec._709)
+const vec3 yCoeff_709 = vec3( 0.2126, 0.7152, 0.0722 );
+
+float luminance( in vec3 v )
+{
+  return dot( v, yCoeff_709 );
+}
+
+vec3 RGBToYPbPr( in vec3 v )
+{
+    vec3 ypp;
+    ypp.x = luminance( v );
+    ypp.y = 0.5 * (v.b - ypp.x) / (1.0 - yCoeff_709.b);
+    ypp.z = 0.5 * (v.r - ypp.x) / (1.0 - yCoeff_709.r);
+
+    return ypp;
+}
+
+vec3 YPbPrToRGB( in vec3 v )
+{
+    vec3 outRGB;
+    outRGB.x = dot(vec3(1.0, 0.0, 1.575), v);
+    outRGB.y = dot(vec3(1.0, -0.187, -0.468), v);
+    outRGB.z = dot(vec3(1.0, 1.856, 0.0), v);
+
+    return outRGB;
+}
+
+#endif