function premultiplyTintToRgba(tint, alpha, out, premultiply) {
    out = out || new Float32Array(4);
    out[0] = ((tint >> 16) & 0xFF) / 255.0;
    out[1] = ((tint >> 8) & 0xFF) / 255.0;
    out[2] = (tint & 0xFF) / 255.0;
    if (premultiply || premultiply === undefined) {
        out[0] *= alpha;
        out[1] *= alpha;
        out[2] *= alpha;
    }
    out[3] = alpha;
    return out;
}
converts integer tint and float alpha to vec4 form, premultiplies by default
@memberof PIXI.utils
@function premultiplyTintToRgba
@param {number} tint - input tint
@param {number} alpha - alpha param
@param {Float32Array} [out] - output
@param {boolean} [premultiply=true] - do premultiply it
@returns {Float32Array} vec4 rgba