129 lines
4.6 KiB
C#
129 lines
4.6 KiB
C#
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using System;
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using System.Collections.Generic;
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using FarseerPhysics.Dynamics;
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namespace FarseerPhysics.Controllers
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{
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/// <summary>
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/// Put a limit on the linear (translation - the movespeed) and angular (rotation) velocity
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/// of bodies added to this controller.
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/// </summary>
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public class VelocityLimitController : Controller
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{
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public bool LimitAngularVelocity = true;
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public bool LimitLinearVelocity = true;
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private List<Body> _bodies = new List<Body>();
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private float _maxAngularSqared;
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private float _maxAngularVelocity;
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private float _maxLinearSqared;
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private float _maxLinearVelocity;
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/// <summary>
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/// Initializes a new instance of the <see cref="VelocityLimitController"/> class.
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/// Sets the max linear velocity to Settings.MaxTranslation
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/// Sets the max angular velocity to Settings.MaxRotation
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/// </summary>
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public VelocityLimitController()
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: base(ControllerType.VelocityLimitController)
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{
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MaxLinearVelocity = Settings.MaxTranslation;
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MaxAngularVelocity = Settings.MaxRotation;
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}
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/// <summary>
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/// Initializes a new instance of the <see cref="VelocityLimitController"/> class.
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/// Pass in 0 or float.MaxValue to disable the limit.
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/// maxAngularVelocity = 0 will disable the angular velocity limit.
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/// </summary>
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/// <param name="maxLinearVelocity">The max linear velocity.</param>
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/// <param name="maxAngularVelocity">The max angular velocity.</param>
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public VelocityLimitController(float maxLinearVelocity, float maxAngularVelocity)
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: base(ControllerType.VelocityLimitController)
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{
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if (maxLinearVelocity == 0 || maxLinearVelocity == float.MaxValue)
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LimitLinearVelocity = false;
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if (maxAngularVelocity == 0 || maxAngularVelocity == float.MaxValue)
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LimitAngularVelocity = false;
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MaxLinearVelocity = maxLinearVelocity;
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MaxAngularVelocity = maxAngularVelocity;
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}
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/// <summary>
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/// Gets or sets the max angular velocity.
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/// </summary>
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/// <value>The max angular velocity.</value>
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public float MaxAngularVelocity
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{
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get { return _maxAngularVelocity; }
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set
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{
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_maxAngularVelocity = value;
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_maxAngularSqared = _maxAngularVelocity * _maxAngularVelocity;
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}
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}
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/// <summary>
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/// Gets or sets the max linear velocity.
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/// </summary>
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/// <value>The max linear velocity.</value>
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public float MaxLinearVelocity
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{
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get { return _maxLinearVelocity; }
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set
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{
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_maxLinearVelocity = value;
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_maxLinearSqared = _maxLinearVelocity * _maxLinearVelocity;
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}
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}
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public override void Update(float dt)
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{
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foreach (Body body in _bodies)
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{
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if (!IsActiveOn(body))
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continue;
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if (LimitLinearVelocity)
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{
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//Translation
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// Check for large velocities.
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float translationX = dt * body.LinearVelocityInternal.X;
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float translationY = dt * body.LinearVelocityInternal.Y;
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float result = translationX * translationX + translationY * translationY;
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if (result > dt * _maxLinearSqared)
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{
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float sq = (float)Math.Sqrt(result);
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float ratio = _maxLinearVelocity / sq;
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body.LinearVelocityInternal.X *= ratio;
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body.LinearVelocityInternal.Y *= ratio;
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}
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}
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if (LimitAngularVelocity)
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{
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//Rotation
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float rotation = dt * body.AngularVelocityInternal;
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if (rotation * rotation > _maxAngularSqared)
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{
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float ratio = _maxAngularVelocity / Math.Abs(rotation);
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body.AngularVelocityInternal *= ratio;
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}
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}
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}
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}
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public void AddBody(Body body)
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{
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_bodies.Add(body);
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}
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public void RemoveBody(Body body)
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{
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_bodies.Remove(body);
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}
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}
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}
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