/// <summary>
/// Returns the <see cref="Sprite"/> with the specified
/// reference or null if no such sprite exists.
/// </summary>
/// <param name="spriteRef">Sprite reference</param>
/// <returns>Sprite</returns>
public Sprite this[SpriteReference spriteRef]
{
get
{
Sprite sprite;
return(_sprites.TryGetValue(spriteRef.Id, out sprite) ? sprite : null);
}
}
private void OnDraw(EngineDrawEventArgs e)
{
if (Sprite != _oldSprite)
{
// Sprite has changed since last draw
_rotateEffect?.Dispose();
_rotateEffect = null;
}
if (Sprite == SpriteReference.Empty)
{
return;
}
var transform = Entity.GetBehavior <TransformBehavior>();
var coords = Entity.Level.RootEntity.GetImplementation <ICoordinateSystem>();
var sprite = Sprite.Resolve(Entity);
if (transform == null)
{
throw new InvalidOperationException($"No {nameof(TransformBehavior)} is attached");
}
if (coords != null && sprite != null)
{
var worldPos = transform.Position;
var worldRect = new Rect(
worldPos.X - transform.Scale.X * sprite.Size.X / 2,
worldPos.Y - transform.Scale.X * sprite.Size.Y / 2,
transform.Scale.X * sprite.Size.X,
transform.Scale.X * sprite.Size.Y);
var dipsRect = coords.TransformToDips(worldRect);
ICanvasImage renderImage;
// If rotation is 0 we can draw the sprite directly.
// Otherwise, use a Transform2DEffect to rotate.
if (Math.Abs(transform.Rotation) <= float.Epsilon)
{
renderImage = sprite.Image;
}
else
{
_rotateEffect = _rotateEffect ?? new Transform2DEffect {
Source = sprite.Image
};
_rotateEffect.TransformMatrix = Matrix3x2.CreateRotation(transform.RotationRadians);
renderImage = _rotateEffect;
}
e.DrawingSession.DrawImage(renderImage, dipsRect, renderImage.GetBounds(e.DrawingSession));
}
_oldSprite = Sprite;
}
