@Override
    public void onDraw() {
        GLES20.glUniform1f(getHandle("red"), red);
        GLES20.glUniform1f(getHandle("green"), green);
        GLES20.glUniform1f(getHandle("blue"), blue);
        GLES20.glUniform1f(getHandle("brightness"), brightness);
        GLES20.glUniform1f(getHandle("saturation"), saturation);
        GLES20.glUniform1f(getHandle("contrast"), contrast);
    }
Adjusts the individual RGB channels of an image
red: Normalized values by which each color channel is multiplied. The range is from 0.0 up, with 1.0 as the default.
green:
blue:
dkplayer-sample/src/main/java/xyz/doikki/dkplayer/widget/render/gl2/filter/GlRGBFilter.java