function changeLightMode(val) {
    if (!val && lightMode) {
        lightMode = false;
        DPR = window.devicePixelRatio || 1;
        globalScope.scale *= DPR;
    } else if (val && !lightMode) {
        lightMode = true;
        globalScope.scale /= DPR;
        DPR = 1
        $('#miniMap').fadeOut('fast');
    }
    resetup();
}
turn light mode on
@param {boolean} val -- new value for light mode
@category engine