@
ryd994 就是形如这样的代码，摘录自楼主的 Github。一点注释都没有，后人完全没办法维护。
void main()
{
vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
vec4 textureColor2 = texture2D(inputImageTexture2, textureCoordinate2);
float maskY = 0.2989 * colorToReplace.r + 0.5866 * colorToReplace.g + 0.1145 * colorToReplace.b;
float maskCr = 0.7132 * (colorToReplace.r - maskY);
float maskCb = 0.5647 * (colorToReplace.b - maskY);
float Y = 0.2989 * textureColor.r + 0.5866 * textureColor.g + 0.1145 * textureColor.b;
float Cr = 0.7132 * (textureColor.r - Y);
float Cb = 0.5647 * (textureColor.b - Y);
// float blendValue = 1.0 - smoothstep(thresholdSensitivity - smoothing, thresholdSensitivity , abs(Cr - maskCr) + abs(Cb - maskCb));
float blendValue = 1.0 - smoothstep(thresholdSensitivity, thresholdSensitivity + smoothing, distance(vec2(Cr, Cb), vec2(maskCr, maskCb)));
gl_FragColor = mix(textureColor, textureColor2, blendValue);
}