This method is based off of Nick Gravelyn's Tile Engine series where he loads in basic Tile Layers for his map. I take his method and expand upon it to include a dedicated layer of the map for objects (i.e. players, npcs, items, chests, portals, etc). I'll show you the code first and then explain it.
private static ObjectLayer ProcessFile(ContentManager content, string fileName)
{
ObjectLayer objectLayer;
List<List<int>> tempLayout = new List<List<int>>();
string playerTexture = null;
using (StreamReader reader = new StreamReader(fileName))
{
bool readingLayout = false;
bool readingPlayer = false;
while (!reader.EndOfStream)
{
string line = reader.ReadLine().Trim();
if (string.IsNullOrEmpty(line))
continue;
if (line.Contains("[Player]"))
{
readingPlayer = true;
readingLayout = false;
}
if (line.Contains("[Layout]"))
{
readingLayout = true;
readingPlayer = false;
}
else if (readingPlayer)
{
playerTexture = reader.ReadLine();
}
else if (readingLayout)
{
List<int> row = new List<int>();
string[] cells = line.Split(' ');
foreach (string c in cells)
{
if (!string.IsNullOrEmpty(c))
row.Add(int.Parse(c));
}
tempLayout.Add(row);
}
}
}
int width = tempLayout[0].Count;
int height = tempLayout.Count;
objectLayer = new ObjectLayer(width, height);
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
objectLayer.SetCellIndex(x, y, tempLayout[y][x]);
switch (objectLayer.GetCellIndex(x, y))
{
case 1:
objectLayer.player = new Player(content.Load<Texture2D>(playerTexture));
objectLayer.player.Position = new Vector2(x * Engine.TileWidth,
y * Engine.TileHeight);
objectLayer.player.OriginOffset = new Vector2(32, 64); // NEED TO NOT HARDCODE THESE VALUES
break;
case 0:
break;
}
}
}
return objectLayer;
}
The first thing we do here is declare our List<List<int>> for our tempLayout of the map layer. This will allow us to read in each cell of the map from our file. I also declare a string for the player's Texture because the constructor for the player requires a Texture2D and I can't access objectLayer.player until after objectLayer has been instantiated. After the playerTexture, we declare that we're using the StreamReader class and begin reading in our file.
First off inside the while loop we read the first line of the file with string line = reader.ReadLine().Trim();. This reads in the first line of the ObjectLayer file. Here is that file for reference:
[Player]
Sprites/playerSheet
[Layout]
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
As you can see, the first line is "[Player]". This sets the "readingPlayer" variable to true and moves to the "if (readingPlayer)" section of the loop. We then simply read in the path to the player's texture file. Next we move onto reading in the Layout of the map.
This section is very similar to Nick's method, except that after we read in the map to the tempLayout list of list<int>, we loop through the map to do two things. The first is to set each cell index, and the second to run a switch statement on each cell, which at this point only recognizes and looks for a '1' (the player starting cell). Once we have found the player starting cell, we instantiate the objectLayer's player variable and set it's position to that of the cell where it was located in the objectLayer's map.
We use this method in our game1.cs file where we call:
tileMap.ObjectLayer = ObjectLayer.FromFile(Content, "Content/Layers/Objects.olayer");
This line of code is identical to the method used in Nick's Tile Engine, except it is a type ObjectLayer instead of TileLayer. I hope this has been fairly easy to understand, but I understand if it is a lot of code to take in. If you are confused, please read over the code a few times and really ask yourself what each piece is doing. As always, I am willing to answer basic questions about this code and will try to help you out as best I can. Please leave me a comment if you have a question you simply cannot find the answer to.
Until next time!
