function InitMap(jsonObj){
    var tileLayer = null, objLayer = null;
    for(var i = 0; i < jsonObj.layers.length; i++){
        if(jsonObj.layers[i].type == "tilelayer") tileLayer = jsonObj.layers[i];
        if(jsonObj.layers[i].type == "objectgroup") objLayer = jsonObj.layers[i];
    }
    if(tileLayer){
        map = [];
        for(var x = 0; x < tileLayer.width; x++){
            map[x] = [];
            for(var y = 0; y < tileLayer.height; y++){
                map[x][y] = tileLayer.data[x + y * tileLayer.width] - 1;
            }
        }
    }
    if(objLayer){
        for(var i = 0; i < objLayer.objects.length; i++){
            if(!entityConstructors.hasOwnProperty(objLayer.objects[i].type)) continue;
            var e = new entityConstructors[objLayer.objects[i].type]();
            e.Init(objLayer.objects[i]);
             entities.push(e);
        }
    }
}