RokidXRUnity/Runtime/Scripts/Input/Interaction/ProximityField/CylinderProximityField.cs

using UnityEngine;
using UnityEngine.Assertions;

namespace Rokid.UXR.Interaction {
	public class CylinderProximityField : MonoBehaviour,
	    IProximityField, ICurvedPlane
	{
	    [SerializeField]
	    private Cylinder _cylinder;
	
	    [SerializeField]
	    private float _rotation = 0f;
	
	    [SerializeField, Range(0f, 360f)]
	    private float _arcDegrees = 360;
	
	    [SerializeField]
	    private float _bottom = -1f;
	
	    [SerializeField]
	    private float _top = 1f;
	
	    /// <summary>
	    /// 提供一个ICurvePlane复写本地的属性
	    /// </summary>
	    [Tooltip("Providing an ICurvedPlane here will " +
	        "override all other local properties")]
	    [SerializeField, Optional, Interface(typeof(ICurvedPlane))]
	    private MonoBehaviour _curvedPlane;
	
	    private ICurvedPlane CurvedPlane;
	
	    public Cylinder Cylinder => _cylinder;
	
	    public float ArcDegrees
	    {
	        get => _arcDegrees;
	        set => _arcDegrees = value;
	    }
	    public float Rotation
	    {
	        get => _rotation;
	        set => _rotation = value;
	    }
	    public float Bottom
	    {
	        get => _bottom;
	        set => _bottom = value;
	    }
	    public float Top
	    {
	        get => _top;
	        set => _top = value;
	    }
	
	    protected virtual void Awake()
	    {
	        CurvedPlane = _curvedPlane != null ?
	                      _curvedPlane as ICurvedPlane :
	                      this;
	    }
	
	    protected virtual void Start()
	    {
	        Assert.IsNotNull(CurvedPlane);
	        Assert.IsNotNull(CurvedPlane.Cylinder);
	    }
	
	    public Vector3 ComputeClosestPoint(Vector3 point)
	    {
	        return ComputeClosestPoint(CurvedPlane, point);
	    }
	
	    /// <summary>
	    /// 最近点的计算
	    /// </summary>
	    /// <param name="curvedPlane"></param>
	    /// <param name="point"></param>
	    /// <returns></returns>
	    private static Vector3 ComputeClosestPoint(ICurvedPlane curvedPlane, Vector3 point)
	    {
	        RKLog.Debug($"CylinderProximityField ComputeClosestPoint");
	
	        Vector3 localPoint = curvedPlane.Cylinder.transform.InverseTransformPoint(point);
	
	        if (curvedPlane.Top > curvedPlane.Bottom)
	        {
	            localPoint.y = Mathf.Clamp(localPoint.y, curvedPlane.Bottom, curvedPlane.Top);
	        }
	
	        if (curvedPlane.ArcDegrees < 360)
	        {
	            float angle = Mathf.Atan2(localPoint.x, localPoint.z) * Mathf.Rad2Deg % 360;
	            float rotation = curvedPlane.Rotation % 360;
	
	            if (angle > rotation + 180)
	            {
	                angle -= 360;
	            }
	            else if (angle < rotation - 180)
	            {
	                angle += 360;
	            }
	
	            angle = Mathf.Clamp(angle, rotation - curvedPlane.ArcDegrees / 2f,
	                                       rotation + curvedPlane.ArcDegrees / 2f);
	
	            localPoint.x = Mathf.Sin(angle * Mathf.Deg2Rad) * curvedPlane.Cylinder.Radius;
	            localPoint.z = Mathf.Cos(angle * Mathf.Deg2Rad) * curvedPlane.Cylinder.Radius;
	        }
	        else
	        {
	            Vector3 nearestPointOnCenterAxis = new Vector3(0f, localPoint.y, 0f);
	            float distanceFromCenterAxis = Vector3.Distance(localPoint,
	                                                            nearestPointOnCenterAxis);
	            localPoint = Vector3.MoveTowards(localPoint,
	                                             nearestPointOnCenterAxis,
	                                             distanceFromCenterAxis - curvedPlane.Cylinder.Radius);
	        }
	
	        return curvedPlane.Cylinder.transform.TransformPoint(localPoint);
	    }
	}
	
}