Sprite Sheets - Learning C# by Programming Games - page 264

currently selected. These are all the member variables in the SpriteSheet class:

protected Texture2D sprite;
protected int sheetIndex;
protected int sheetColumns;
protected int sheetRows;
protected bool mirror;

In the constructor, we initially assign the value 1 to the sheetColumns and sheetRows
variables. The sheet index is passed along as a parameter and has 0 as the default
value (in other words, the first element in the sheet). We also retrieve the sprite using
the asset manager:

sprite = PenguinPairs.AssetManager.GetSprite(assetname);
this .sheetIndex = sheetIndex;
this .sheetColumns = 1;
this .sheetRows = 1;

Now we can use the string .Split method to find out if we need to modify the
column and row sizes. The Split method splits a string into substrings and we can
pass along one or more characters that are used as delimiters. Here we split the string
using the '@' sign as a delimiter:

string [] assetSplit = assetname.Split('@');

As you can see, the result of calling the Split method on a string is an array of
string objects. If the delimiter character does not appear in the string, the number of
elements in the assetSplit variable will be 1 (the original string). So, if the length of
the assetSplit array is greater than 1, we know that the file name contains information
about the dimensions of the sheet. What we also know in that case, is that the last
element of the array contains that information. We can easily handle this in an if
instruction:

if (assetSplit.Length <= 1)
return ; // we're done
string sheetNrData = assetSplit[assetSplit.Length −

1];

// deal with the sheet dimension data

As you can see, we store that last element in a new local variable which now contains
the string describing the sheet dimensions. We use the Split method one more time,
to extract the actual dimensions from that string:

string [] colrow = sheetNrData.Split('x');

Again, there are two possibilities here. The colrow array contains either one or two
elements. In both cases, we have to convert the first string element in the array to an
int and store it in the sheetColumns variable: