65 lines
2.0 KiB
GLSL
65 lines
2.0 KiB
GLSL
/*a fast implementation of the chromakey program
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(c) 2008 Edward Cannon (adapted to GLSL by Olive Team)
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feel free to use or modify at will*/
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/*the follwing three functions convert RGB into YCbCr in the same manner as in JPEG images*/
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uniform sampler2D tex;
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varying vec2 vTexCoord;
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uniform vec3 key_color;
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uniform float tola;
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uniform float tolb;
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uniform bool opt;
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uniform int mode;
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float rgb2y (vec3 c) {
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/*a utility function to convert colors in RGB into YCbCr*/
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return (0.299*c.r + 0.587*c.g + 0.114*c.b);
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}
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float rgb2cb (vec3 c) {
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/*a utility function to convert colors in RGB into YCbCr*/
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return (0.5 + -0.168736*c.r - 0.331264*c.g + 0.5*c.b);
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}
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float rgb2cr (vec3 c) {
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/*a utility function to convert colors in RGB into YCbCr*/
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return (0.5 + 0.5*c.r - 0.418688*c.g - 0.081312*c.b);
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}
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float colorclose(float Cb_p,float Cr_p,float Cb_key,float Cr_key,float tola,float tolb) {
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/*decides if a color is close to the specified hue*/
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float temp = sqrt(((Cb_key-Cb_p)*(Cb_key-Cb_p))+((Cr_key-Cr_p)*(Cr_key-Cr_p)));
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if (temp < tola) {return (0.0);}
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if (temp < tolb) {return ((temp-tola)/(tolb-tola));}
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return (1.0);
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}
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void main(void) {
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float cb_key = rgb2cb(key_color);
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float cr_key = rgb2cr(key_color);
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vec4 texture_color = texture2D(tex, vTexCoord);
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float cb = rgb2cb(texture_color.rgb);
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float cr = rgb2cr(texture_color.rgb);
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float mask = colorclose(cb, cr, cb_key, cr_key, (tola/100.0), (tolb/100.0));
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if (mode == 0) { // composite
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//float submask = 1.0-mask;
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float submask = 0.0;
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texture_color.r = max(texture_color.r - submask*key_color.r, 0.0) + submask;
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texture_color.g = max(texture_color.g - submask*key_color.g, 0.0) + submask;
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texture_color.b = max(texture_color.b - submask*key_color.b, 0.0) + submask;
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texture_color.a *= mask;
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// premultiply
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texture_color.rgb *= texture_color.a;
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} else if (mode == 1) { // alpha
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texture_color.rgb = vec3(mask);
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} else if (mode == 2) { // original
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}
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gl_FragColor = texture_color;
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} |