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Posted: **Mon Jul 29, 2019 1:59 pm**

Scripting 14 - RayCast and HitTest

Scripting in SFD assumes you have a fair knowledge of C#.

The following code demonstrates how to perform RayCasts in the world between two points. Available in v.1.3.0.

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// Example script how to RayCast in the world from a player and show some debugging information about the hit objects while testing the map in the editor.
public void OnStartup()
{
	Events.UpdateCallback.Start(OnUpdate, 0);	
}

public void OnUpdate(float ms)
{
	IUser[] users = Game.GetActiveUsers();
	IPlayer plr = (users != null && users.Length > 0 ? users[0].GetPlayer() : null); // any player instance
	
	if (plr != null) {
		Vector2 worldPos = plr.GetWorldPosition() + Vector2.UnitY * 12f;
		Vector2 worldPosEnd = worldPos + plr.AimVector * 100f;
		
		if (Game.IsEditorTest) {
			Game.DrawLine(worldPos, worldPosEnd, Color.Red);
		}
		
		// RayCastInput offers some filtering capabilities, for now just filter on everything with a set CategoryBit (effectively ignoring background objects).
		RayCastInput rci = new RayCastInput() { IncludeOverlap = true, MaskBits = 0xFFFF, FilterOnMaskBits = true };
		// You can also filter on specific types. If you only want to raycast players you would add the IPlayer type to the Types array property: rci.Types = new Type[1] { typeof(IPlayer) };
		RayCastResult[] results = Game.RayCast(worldPos, worldPosEnd, rci);
		foreach(RayCastResult result in results)	{
		
			if (Game.IsEditorTest) {
				Game.DrawCircle(result.Position, 1f, Color.Yellow);
				Game.DrawLine(result.Position, result.Position + result.Normal * 5f, Color.Yellow);
				Game.DrawArea(result.HitObject.GetAABB(), Color.Yellow);
				Game.DrawText(result.HitObject.UniqueID.ToString(), result.Position, Color.Yellow);
			}
			
			// Destroy nearby glass that the player is looking at
			if (result.Fraction < 0.3f && result.HitObject.Name.IndexOf("glass", StringComparison.OrdinalIgnoreCase) >= 0) {
				result.HitObject.Destroy();
			}
			
		}
	}

}

To perform a HitTest on any IObject simply use the bool IObject.HitTest(Vector2 position) function. You can also perform RayCasts on individual IObjects.

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IObject obj = ... // any IObject instance

if (obj.HitTest(Vector2.Zero)) {
	// Object overlaps the center of the world
}
Vector2 pA = Vector2.Zero;
Vector2 pB = Vector2.UnitX * 100f;
if (obj.RayCast(pA, pB, true).Hit) {
	// Object hit between pA and pB
}

ScriptAPI Implementation for RayCast and HitTest:

► Show Spoiler

Code: Select all

In the Game class:
		
	/// <summary>
	/// Performs a ray cast in the world.
	/// Use with care as it can get CPU intense depending on your raycast distance and how many you perform each update!
	/// Does not work with far background objects.
	/// </summary>
	/// <param name="start">Start position</param>
	/// <param name="end">End position</param>
	/// <param name="input">Input parameters</param>
	/// <returns>RayCastResult[] hit results based on RayCastInput data.</returns>
	public abstract RayCastResult[] RayCast(Vector2 start, Vector2 end, RayCastInput input);
	
	
	
In the IObject class:
	/// <summary>
	/// Performs a ray cast on this specific object, returning the hit result.
	/// Always returns a false hit if the object is disposed or removed.
	/// </summary>
	/// <param name="start">Start world position</param>
	/// <param name="end">End world position</param>
	/// <param name="value">RayCastResult</param>
	public abstract RayCastResult RayCast(Vector2 start, Vector2 end);

	/// <summary>
	/// Performs a ray cast on this specific object, returning the hit result.
	/// Always returns a false hit if the object is disposed or removed.
	/// </summary>
	/// <param name="start">Start world position</param>
	/// <param name="end">End world position</param>
	/// <param name="includeOverlap">If overlapping objects at the start of the RayCast should be included.</param>
	/// <param name="value">RayCastResult</param>
	public abstract RayCastResult RayCast(Vector2 start, Vector2 end, bool includeOverlap);

	/// <summary>
	/// Performs a hittest on this object.
	/// </summary>
	/// <param name="position">World position</param>
	/// <returns>True if position overlaps the object, false otherwise.</returns>
	public abstract bool HitTest(Vector2 position);
	

	
Help structures	for in and out data:
	/// <summary>
    /// RayCastFilterMode for the RayCastInput filters.
    /// </summary>
    public enum RayCastFilterMode
    {
        /// <summary>
        /// 0, Any (True or False)
        /// </summary>
        Any = 0,
        
        /// <summary>
        /// 1, True
        /// </summary>
        True = 1,

        /// <summary>
        /// 2, False
        /// </summary>
        False = 2
    }

    /// <summary>
    /// RayCastInput
    /// </summary>
    [Serializable()]
    public struct RayCastInput
    {
        /// <summary>
        /// Types that the RayCast would accept for collision.
        /// </summary>
        public Type[] Types;

        /// <summary>
        /// The collision mask bits. This states the categories that this RayCast would accept for collision if FilterOnMaskBits is set to true.
        /// </summary>
        public UInt16 MaskBits;

        /// <summary>
        /// If MaskBits should be used for filtering.
        /// </summary>
        public bool FilterOnMaskBits;

        /// <summary>
        /// If melee attacks are blocked by this object or not.
        /// </summary>
        public RayCastFilterMode BlockMelee;

        /// <summary>
        /// If projectiles hit this object or not.
        /// </summary>
        public RayCastFilterMode ProjectileHit;

        /// <summary>
        /// If explosions are blocked by this object or not.
        /// </summary>
        public RayCastFilterMode BlockExplosions;

        /// <summary>
        /// If fire is blocked by this object or not.
        /// </summary>
        public RayCastFilterMode BlockFire;

        /// <summary>
        /// If overlapping objects at the start of the RayCast should be included.
        /// </summary>
        public bool IncludeOverlap;

        /// <summary>
        /// If you only care about the closest result you should enable this as it optimizes the RayCast and always returns one RayCastInput result.
        /// </summary>
        public bool ClosestHitOnly;
    }

    /// <summary>
    /// RayCastResult
    /// </summary>
    [Serializable()]
    public struct RayCastResult
    {
        /// <summary>
        /// If a hit was registered.
        /// </summary>
        public readonly bool Hit;

        /// <summary>
        /// Hit object ID.
        /// </summary>
        public readonly int ObjectID;

        /// <summary>
        /// Hit object.
        /// </summary>
        public readonly IObject HitObject;

        /// <summary>
        /// If the hit object is a player.
        /// </summary>
        public readonly bool IsPlayer;

        /// <summary>
        /// Fraction of the input start/end positions.
        /// </summary>
        public readonly float Fraction;

        /// <summary>
        /// Hit position.
        /// </summary>
        public readonly Vector2 Position;

        /// <summary>
        /// Hit normal. Is Vector2.Zero for results with fraction 0 where the start position overlaps the object if IncludeOverlap is enabled.
        /// </summary>
        public readonly Vector2 Normal;

    }