Rendering Text - C# Game Programming: For Serious Game Creation - page 153

float xOffset = ((float)sprite.Data.XOffset) / 2;
float yOffset = ((float)sprite.Data.YOffset) / 2;
sprite.Sprite.SetPosition(currentX + xOffset, currentY - yOffset);
currentX += sprite.Data.XAdvance;
_bitmapText.Add(sprite);
}
}
}
The class is quite straightforward. The CreateText function is the heart of the
class; it positions the character sprites correctly. For each sprite, the Char-
acterData is checked and the x position is advanced by the amount specified.
Each character sprite also has an offset. All sprites are positioned around their
center, but the offset values are taken from the top left. To convert this offset to a
central position, the offset values are halved. As the offsets are integers, they need
to be converted to floating point numbers before being divided. If the numbers
aren't cast to floats, then the floating point information is thrown away and the
text letters won't be aligned correctly.
The final class to consider is the Font class. The Font class holds the dictionary
that translates a character into a CharacterData object. Given a word or
sentence, all the letters can be used to index the dictionary and a set Char-
acterData will be returned, ready to be used to create text sprites.
public class Font
{
Texture _texture;
Dictionary<char, CharacterData> _characterData;
public Font(Texture texture, Dictionary<char, CharacterData>
characterData)
{
_texture = texture;
_characterData = characterData;
}
public CharacterSprite CreateSprite(char c)
{
CharacterData charData = _characterData[c];
Sprite sprite = new Sprite();
sprite.Texture = _texture;
// Setup UVs
Point topLeft = new Point((float)charData.X / (float)_texture.Width,