I am making a basic platformer, my first ever game. I've run into a bit of a problem. So far the game only has one level, and it is loaded from a .txt file. However I'd like to have a sort of an Angry Birdish world/level selection screen.
The plan is to have an icon for each level visible, but only so far completed levels and the next one accessible. Also for the completed levels the score (stars, whatever) would be displayed under the icon.
I do not wish to load the levels from XML, at least not yet. Only the persistent world data that needs to be read AND written. I assume the easiest way is to load even the formatting of the level selection screen from XML, and not use the method i currently use (text files).
I could do this with text files, I suppose, but I really do not relish the idea of writing and sorting through the file. I then discovered that XML-files should be a bit less problematic in this regard. However additional problem rises from the fact tht I've never ever worked with XML-files before.
Could someone point me in a direction of a tutorial for this sort of things, or some sample you might have come accross that accomplishes at least relatively similar results. I don't expect anyone to do the coding for me, but if you have pointers or time and patience to provide a sample, I'd appreciate it a lot.
After some further digging and fumbling with tutorials for older XNA versions I managed to produce following save/load class:
namespace SaveLoadXML
{
class SaveLoad
{
public LevelInfo Load (int id)
{
LevelInfo level;
// Get the path of the save game
string fullpath = "World.xml";
// Open the file
FileStream stream = File.Open(fullpath, FileMode.OpenOrCreate,
FileAccess.Read);
try
{
// Read the data from the file
XmlSerializer serializer = new XmlSerializer(typeof(LevelInfo));
level = (LevelInfo)serializer.Deserialize(stream);
}
finally
{
// Close the file
stream.Close();
}
return (level);
}
public void Save (LevelInfo level, int id)
{
// Get the path of the save game
string fullpath = "World.xml";
// Open the file, creating it if necessary
FileStream stream = File.Open(fullpath, FileMode.OpenOrCreate);
try
{
// Convert the object to XML data and put it in the stream
XmlSerializer serializer = new XmlSerializer(typeof(LevelInfo));
serializer.Serialize(stream, level);
}
finally
{
// Close the file
stream.Close();
}
}
}
}
Now I started to think, is there a way to target a specific part of the XML-file, or is the writing always just from the start? Almost all of the examples I saw had a condition at the start: if the file exists, delete it and then write.
I assume I could (or even should?) make a list of LevelInfo objects and just load them all at once, as there is no real need to load a single LevelInfo anyway. On the saving however, do I need to load the previous state (old list) and then manipulate the list regarding the certain indexes involved, and then delete te file, and save it again.
This might open an easy way for the system to fail if something goes wrong in the saving or power fails for example. The whole file would be lost or corrupt. I suppose this ould be countered with using back-up file and then checking the integrity of the main file, but now it's starting to feel like quite a mountain to climb for a beginner like me.
Having tried this question on GameDev, I'll just clarify the main question here:
1) Can I save only info about one or two levels in the XML-file containing info for all levels? ie. can I use some indexing to point the write operation to a particular section that would then be overwritten/replaced.
2) If not, is there any way to safely load all info from file, delete file, save all info after modifying it where needed.
After some looking into this Json stuff, I've managed to successfully serialize test level information. However, de-serialization fails as I have a rectangle as a part of the object. Error is as follows:
Error converting value "{X:1 Y:1 Width:1 Height:1}" to type 'Microsoft.Xna.Framework.Rectangle'. Path '[0].Rectangle', line 6, position 46.
class LevelInfo
{
public int ID { get; set; }
public Vector2 Dimensions { get; set; }
public Vector2 Position { get; set; }
public Rectangle Rectangle { get; set; }
public int Stars { get; set; }
public string Text { get; set; }
}
class SaveLoadJSON
{
public static List<LevelInfo> Load()
{
List<LevelInfo> levels = new List<LevelInfo>();
using (StreamReader file = File.OpenText("World.json"))
{
JsonSerializer serializer = new JsonSerializer();
levels = (List<LevelInfo>)serializer.Deserialize(file, typeof(List<LevelInfo>));
}
return levels;
}
public static void Save(List<LevelInfo> levels)
{
if (File.Exists("World.json"))
{
File.Delete("World.json");
}
using (FileStream fs = File.Open("World.json", FileMode.CreateNew))
using (StreamWriter sw = new StreamWriter(fs))
using (JsonWriter jw = new JsonTextWriter(sw))
{
jw.Formatting = Formatting.Indented;
JsonSerializer serializer = new JsonSerializer();
serializer.Serialize(jw, levels);
}
}
}
Is there a way to work around this? Preferably a relatively simple way for a simple beginner like me.
Or alternatively, is there a way to omit the rectangle information to begin with, and maybe add it later? If I input nothing to the rectangle, it still is added to Json-file with 0 values. I do need the rectangle info for the drawing.
