/// <summary>
/// Constructs a new instance of the <see cref="Entity" /> class
/// with the properties populated from XML
/// </summary>
/// <param name="xml">XML node to read the properties from</param>
/// <param name="graphicSize">Size of the graphic the entity has</param>
public Entity(XmlNode xml, Size graphicSize)
{
if (xml == null)
{
throw new ArgumentNullException(nameof(xml));
}
// Read required properties
ID = xml.Attributes["id"] == null ? null : xml.Attributes["id"].Value;
Type = xml.Attributes["type"].Value;
Graphic = xml.Attributes["graphic"].Value;
X = Double.Parse(xml.Attributes["x"].Value);
Y = Double.Parse(xml.Attributes["y"].Value);
Delay = xml.Attributes["delay"] == null ? null : (int?)int.Parse(xml.Attributes["delay"].Value);
// Read extra props
PowerUp = xml.Attributes["powerUp"] == null ? null : xml.Attributes["powerUp"].Value;
LurcherID = xml.Attributes["lurcherId"] == null ? null : xml.Attributes["lurcherId"].Value;
// Default optional types
DestinationX = null;
DestinationY = null;
Speed = null;
// Read properties based on type
switch (Type)
{
case "alien":
case "asteroid":
case "background":
case "debris":
case "nebula":
case "pirate":
case "crate":
case "lurcher":
// Read the properties
double?vX = xml.Attributes["vX"] == null ? null : (double?)Double.Parse(xml.Attributes["vX"].Value);
double?vY = xml.Attributes["vY"] == null ? null : (double?)Double.Parse(xml.Attributes["vY"].Value);
// There are no properties to convert
if (!vX.HasValue || !vY.HasValue)
{
return;
}
// Build vectors
Vector position = new Vector(X, Y);
Vector velocity = new Vector(vX.Value, vY.Value);
// Calculate destination
Vector destination = BRMath.CalculateDestination(X, Y, graphicSize.Width, graphicSize.Height, velocity.X, velocity.Y);
DestinationX = destination.X;
DestinationY = destination.Y;
// Calculate speed
Speed = BRMath.CalculateSpeed(position, destination, velocity);
break;
}
}
/// <summary>
/// Converts the entity to XML
/// </summary>
/// <param name="indention">Indention to apply</param>
/// <returns>Entity XML</returns>
public string ToXml(int indention)
{
// Start building XML
StringBuilder xmlBuilder = new StringBuilder();
// Open the entity
xmlBuilder.AppendFormat("{0}<entity ", new string(' ', indention));
// Append ID if it exists
if (!String.IsNullOrWhiteSpace(ID))
{
xmlBuilder.AppendFormat("id=\"{0}\" ", ID);
}
// Append properties that always exist
xmlBuilder.AppendFormat("type=\"{0}\" ", Type);
xmlBuilder.AppendFormat("graphic=\"{0}\" ", Graphic);
xmlBuilder.AppendFormat("x=\"{0}\" ", X);
xmlBuilder.AppendFormat("y=\"{0}\" ", Y);
// Determine which velocity props to write
if (Type == "police")
{
xmlBuilder.AppendFormat("dX=\"{0}\" ", DestinationX);
xmlBuilder.AppendFormat("dY=\"{0}\" ", DestinationY);
xmlBuilder.AppendFormat("s=\"{0}\" ", Speed);
}
else if (DestinationX.HasValue && DestinationY.HasValue && Speed.HasValue)
{
// Calculate velocity
Vector velocity = BRMath.CalculateVelocity(X, Y, DestinationX.Value, DestinationY.Value, Speed.Value);
xmlBuilder.AppendFormat("vX=\"{0}\" ", velocity.X);
xmlBuilder.AppendFormat("vY=\"{0}\" ", velocity.Y);
}
if (Delay.HasValue)
{
xmlBuilder.AppendFormat("delay=\"{0}\" ", Delay);
}
if (!String.IsNullOrWhiteSpace(PowerUp))
{
xmlBuilder.AppendFormat("powerUp=\"{0}\" ", PowerUp);
}
if (!String.IsNullOrWhiteSpace(LurcherID))
{
xmlBuilder.AppendFormat("lurcherId=\"{0}\" ", LurcherID);
}
// Close the entity
xmlBuilder.Append("/>");
return(xmlBuilder.ToString());
}
