Add a character to the font, where [i]character[/i] is the unicode value, [i]texture[/i] is the texture index, [i]rect[/i] is the region in the texture (in pixels!), [i]align[/i] is the (optional) alignment for the character and [i]advance[/i] is the (optional) advance. Add a kerning pair to the [BitmapFont] as a difference. Kerning pairs are special cases where a typeface advance is determined by the next character. Add a texture to the [BitmapFont]. Clear all the font data. Return the size of a character, optionally taking kerning into account if the next character is provided. Return a kerning pair as a difference. Set the font ascent (number of pixels above the baseline). Set the total font height (ascent plus descent) in pixels.