68 lines
2.3 KiB
GLSL
68 lines
2.3 KiB
GLSL
/*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 following three functions convert RGB into YCbCr in the same manner as in JPEG images*/
|
||
|
||
uniform vec3 key_color;
|
||
uniform float tola;
|
||
uniform float tolb;
|
||
uniform bool opt;
|
||
uniform int mode;
|
||
|
||
float rgb2y (vec3 c) {
|
||
/*a utility function to convert colors from REC.709 RGB into YCbCr*/
|
||
|
||
// This isn’t colour managed and is a huge mess, but in the
|
||
// short term, using correct weights will give significantly
|
||
// more ideal results. The correct weights for REC.709 are
|
||
// 0.2126 R, 0.7152 G, and 0.0722 B. Easy change.
|
||
// The coefficients for YCbCr are calculated off of the
|
||
// REC.709 values.
|
||
return (0.2126*c.r + 0.7152*c.g + 0.0722*c.b);
|
||
}
|
||
|
||
float rgb2cb (vec3 c) {
|
||
/*a utility function to convert colors from REC.709 RGB into YCbCr*/
|
||
return (0.5 + -0.1145721061*c.r - 0.3854278939*c.g + 0.5*c.b);
|
||
}
|
||
|
||
float rgb2cr (vec3 c) {
|
||
/*a utility function to convert colors from REC.709 RGB into YCbCr*/
|
||
return (0.5 + 0.5*c.r - 0.4541529083*c.g - 0.0458470917*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);
|
||
}
|
||
|
||
vec4 process(vec4 texture_color) {
|
||
float cb_key = rgb2cb(key_color);
|
||
float cr_key = rgb2cr(key_color);
|
||
|
||
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));
|
||
|
||
if (mode == 0) { // composite
|
||
//float submask = 1.0-mask;
|
||
float submask = 0.0;
|
||
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;
|
||
|
||
// premultiply
|
||
texture_color.rgb *= texture_color.a;
|
||
} else if (mode == 1) { // alpha
|
||
texture_color.rgb = vec3(mask);
|
||
} else if (mode == 2) { // original
|
||
}
|
||
|
||
return texture_color;
|
||
}
|