147 lines
4.5 KiB
C#
147 lines
4.5 KiB
C#
using System;
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using Microsoft.Xna.Framework;
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namespace Subsurface
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{
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class SteeringManager
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{
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private const float CircleDistance = 2.5f;
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private const float CircleRadius = 0.3f;
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private const float RayCastInterval = 0.5f;
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private ISteerable host;
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private Vector2 steering;
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//the steering amount when avoiding obstacles
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//(needs a separate variable because it's only updated when a raycast is done to detect any nearby obstacles)
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private Vector2 avoidSteering;
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private float rayCastTimer;
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private float wanderAngle;
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public float WanderAngle
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{
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get { return wanderAngle; }
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set { wanderAngle = value; }
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}
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public SteeringManager(ISteerable host)
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{
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this.host = host;
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wanderAngle = ToolBox.RandomFloat(0.0f, MathHelper.TwoPi);
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}
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public void SteeringSeek(Vector2 target, float speed = 1.0f)
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{
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steering += DoSteeringSeek(target, speed);
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}
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public void SteeringWander(float speed = 1.0f)
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{
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steering += DoSteeringWander(speed);
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}
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public void SteeringAvoid(float deltaTime, float speed)
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{
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steering += DoSteeringAvoid(deltaTime, speed);
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}
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public void Update(float speed = 1.0f)
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{
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float steeringSpeed = steering.Length();
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if (steeringSpeed>speed)
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{
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steering = Vector2.Normalize(steering) * Math.Abs(speed);
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}
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host.Steering = steering;
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}
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private Vector2 DoSteeringSeek(Vector2 target, float speed = 1.0f)
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{
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Vector2 targetVel = target - host.Position;
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targetVel = Vector2.Normalize(targetVel) * speed;
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Vector2 newSteering = targetVel - host.Steering;
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if (newSteering==Vector2.Zero) return Vector2.Zero;
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float steeringSpeed = (newSteering + host.Steering).Length();
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if (steeringSpeed > Math.Abs(speed))
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{
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newSteering = Vector2.Normalize(newSteering)*Math.Abs(speed);
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}
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return newSteering;
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}
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private Vector2 DoSteeringWander(float speed = 1.0f)
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{
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Vector2 circleCenter = (host.Velocity == Vector2.Zero) ? new Vector2(speed, 0.0f) : host.Velocity;
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circleCenter = Vector2.Normalize(circleCenter) * CircleDistance;
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Vector2 displacement = new Vector2(
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(float)Math.Cos(wanderAngle),
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(float)Math.Sin(wanderAngle));
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displacement = displacement * CircleRadius;
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float angleChange = 1.5f;
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wanderAngle += ToolBox.RandomFloat(0.0f, 1.0f) * angleChange - angleChange * 0.5f;
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Vector2 newSteering = circleCenter + displacement;
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float steeringSpeed = (newSteering + host.Steering).Length();
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if (steeringSpeed > speed)
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{
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newSteering = Vector2.Normalize(newSteering) * speed;
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}
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return newSteering;
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}
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private Vector2 DoSteeringAvoid(float deltaTime, float speed = 1.0f)
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{
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if (steering == Vector2.Zero || host.Steering == Vector2.Zero) return Vector2.Zero;
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float MaxDistance = 2.0f;
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Vector2 ahead = host.Position + Vector2.Normalize(host.Steering)*MaxDistance;
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if (rayCastTimer <= 0.0f)
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{
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rayCastTimer = RayCastInterval;
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Structure closestStructure = Map.CheckVisibility(host.Position, ahead);
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if (closestStructure == null)
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{
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avoidSteering = Vector2.Zero;
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return Vector2.Zero;
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}
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else
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{
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Vector2 obstaclePosition = Map.LastPickedPosition;
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if (closestStructure.IsHorizontal)
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{
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obstaclePosition.Y = closestStructure.SimPosition.Y;
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}
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else
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{
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obstaclePosition.X = closestStructure.SimPosition.X;
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}
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avoidSteering = Vector2.Normalize(Map.LastPickedPosition - obstaclePosition);
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}
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}
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else
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{
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rayCastTimer -= deltaTime;
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}
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return avoidSteering * speed;
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}
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}
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}
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