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uniform sampler2D u_Texture;
uniform vec4 u_Color;
uniform float u_Gamma;
varying vec2 v_TexCoord;
vec3 toYIQ(vec3 rgb){
return mat3( 0.299, 1.0, 0.40462981, 0.587, -0.46081557, -1.0, 0.114, -0.53918443, 0.59537019 ) * rgb;
}
vec3 toRGB(vec3 yiq){
return mat3( 1.0, 1.0, 1.0, 0.5696804, -0.1620848, -0.6590654, 0.3235513, -0.3381869, 0.8901581 ) * yiq;
}
void main() {
vec3 texture = texture2D(u_Texture, v_TexCoord).rgb;
vec3 original = toYIQ(texture);
if (length(original.xy) < .01){
gl_FragColor = vec4(texture,1);
} else {
vec3 targetYIQ = toYIQ(u_Color.rgb);
vec3 originalYIQ = toYIQ(texture);
vec3 yiqColor = vec3(original.x,targetYIQ.yz);
vec3 finalrgb = toRGB(yiqColor);
finalrgb = pow(finalrgb,vec3(1.0/u_Gamma));
gl_FragColor = vec4(finalrgb,u_Color.a);
}
}
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