added chroma key

effects/chromakey.frag

@@ -0,0 +1,55 @@
+/*a fast implementation of the chromakey program 
+(c) 2008 Edward Cannon (adapted to GLSL by Olive Team)
+feel free to use or modify at will*/
+ 
+/*the follwing three functions convert RGB into YCbCr in the same manner as in JPEG images*/ 
+
+uniform sampler2D tex;
+varying vec2 vTexCoord;
+
+uniform vec3 key_color;
+uniform float tola;
+uniform float tolb;
+uniform bool opt;
+ 
+float rgb2y (vec3 c) { 
+   /*a utility function to convert colors in RGB into YCbCr*/ 
+   return (0.299*c.r + 0.587*c.g + 0.114*c.b);
+} 
+ 
+float rgb2cb (vec3 c) { 
+   /*a utility function to convert colors in RGB into YCbCr*/ 
+   return (0.5 + -0.168736*c.r - 0.331264*c.g + 0.5*c.b);
+} 
+ 
+float rgb2cr (vec3 c) { 
+   /*a utility function to convert colors in RGB into YCbCr*/ 
+   return (0.5 + 0.5*c.r - 0.418688*c.g - 0.081312*c.b);
+} 
+ 
+float colorclose(float Cb_p,float Cr_p,float Cb_key,float Cr_key,float tola,float tolb) { 
+   /*decides if a color is close to the specified hue*/ 
+   float temp = sqrt(((Cb_key-Cb_p)*(Cb_key-Cb_p))+((Cr_key-Cr_p)*(Cr_key-Cr_p)));
+   if (temp < tola) {return (0.0);} 
+   if (temp < tolb) {return ((temp-tola)/(tolb-tola));} 
+   return (1.0); 
+}
+ 
+void main(void) {
+   float cb_key = rgb2cb(key_color);
+   float cr_key = rgb2cr(key_color);
+   
+   vec4 texture_color = texture2D(tex, vTexCoord);
+
+   float cb = rgb2cb(texture_color.rgb); 
+   float cr = rgb2cr(texture_color.rgb); 
+   float mask = colorclose(cb, cr, cb_key, cr_key, (tola/100.0), (tolb/100.0));
+   float submask = 1.0-mask;
+
+   texture_color.r = max(texture_color.r - submask*key_color.r, 0.0) + submask;
+   texture_color.g = max(texture_color.g - submask*key_color.g, 0.0) + submask;
+   texture_color.b = max(texture_color.b - submask*key_color.b, 0.0) + submask;
+   texture_color.a *= mask;
+   
+   gl_FragColor = texture_color;
+}

effects/chromakey.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<effect name="Chroma Key" category="Keying">
+	<row name="Key Color">
+		<field type="color" r="0" g="255" b="0" id="key_color"/>
+	</row>
+	<row name="Lower Tolerance">
+		<field type="double" min="0" default="5" max="100" id="tola"/>
+	</row>
+	<row name="Upper Tolerance">
+		<field type="double" min="0" default="25" max="100" id="tolb"/>
+	</row>
+	<shader vert="common.vert" frag="chromakey.frag"/>
+</effect>

effects/common.frag

@@ -4,6 +4,6 @@ uniform sampler2D tex;
 varying vec2 vTexCoord;
 
 void main(void) {
-	vec4 textureColor = texture2D(tex, vec2(vTexCoord.x, vTexCoord.y));
+	vec4 textureColor = texture2D(tex, vTexCoord);
 	gl_FragColor = textureColor;
 }