private TextSprite CreateSprite(object key, string renderedStringBuilder,
int frameNumber, bool cached, GraphicsDevice device)
{
// First try to find an existing sprite to reuse
for (int i = 0; i < sprites.Count; i++)
{
// If it was last used before the immediately previous frame, assume it is free to use:
if (sprites[i].cached == cached && sprites[i].foundOnFrame < frameNumber - 1)
{
TextSpriteInstance instance = sprites[i];
instance.key = key;
instance.renderedStringBuilder = renderedStringBuilder;
instance.foundOnFrame = frameNumber;
sprites[i] = instance;
return(instance.value);
}
}
// If no sprite to reuse was found...
TextSprite sprite = new TextSprite(this, cached);
sprites.Add(new TextSpriteInstance()
{
key = key,
value = sprite,
renderedStringBuilder = renderedStringBuilder,
foundOnFrame = frameNumber,
cached = cached
});
device.AddSprite(sprite);
return(sprite);
}
private TextSprite UpdateStringBuilderInstance(StringBuilder text, int frameNumber, int i)
{
TextSpriteInstance instance = sprites[i];
// If the value of the StringBuilder has changed, re-render it:
if (HasStringBuilderChanged(text, instance.renderedStringBuilder))
{
instance.renderedStringBuilder = text.ToString(); // Allocates memory
instance.value.SetText(instance.renderedStringBuilder); // Causes rendering
}
// Always update the frame number, then insert it back into the list of sprites
instance.foundOnFrame = frameNumber;
sprites[i] = instance;
return(sprites[i].value);
}
private TextSprite GetSprite(string text, bool cached, GraphicsDevice device)
{
int frameNumber = device.CurrentSpriteFrameNumber;
// Strings are immutable, if an instance is matched: use it directly
for (int i = 0; i < sprites.Count; i++)
{
if (ReferenceEquals(sprites[i].key, text) &&
sprites[i].cached == cached && sprites[i].foundOnFrame != frameNumber)
{
TextSpriteInstance instance = sprites[i];
instance.foundOnFrame = frameNumber;
sprites[i] = instance;
return(instance.value);
}
}
// No match found, create one:
TextSprite sprite = CreateSprite(text, null, frameNumber, cached, device);
sprite.SetText(text);
return(sprite);
}