使用Unity实现VR中在黑板上写字（升级篇）（二）----- 加入黑板擦

public static classHelper
{
    /// <summary>
    ///用于比较两个Color32类型是不是一样
    /// </summary>
    /// <param name="origin"></param>
    /// <param name="compare"></param>
    /// <returns></returns>
    public static bool IsEqual(thisColor32 origin, Color32 compare)
    {
        if (origin.g == compare.g && origin.r ==compare.r)
        {
            if (origin.a == compare.a && origin.b ==compare.b)
            {
                return true;
            }
        }
        return false;
    }
    /// <summary>
    ///把num在low1 ~ high1之间的位置，重新映射到low2 ~ high2之间，并限制返回值是low2 ~ high2之间的值;
    /// </summary>
    /// <param name="num"></param>
    /// <param name="low1"></param>
    /// <param name="high1"></param>
    /// <param name="low2"></param>
    /// <param name="high2"></param>
    /// <returns></returns>
    public static float RemapNumberClamped(float num, float low1, float high1, float low2, floathigh2)
    {
        returnMathf.Clamp(RemapNumber(num, low1, high1, low2, high2), Mathf.Min(low2, high2), Mathf.Max(low2, high2));
    }
    /// <summary>
    ///把num在low1 ~ high1之间时代表的值，映射到low2 ~ high2 之间所代表的值
    /// </summary>
    /// <param name="num"></param>
    /// <param name="low1"></param>
    /// <param name="high1"></param>
    /// <param name="low2"></param>
    /// <param name="high2"></param>
    /// <returns></returns>
    public static float RemapNumber(float num, float low1, float high1, float low2, floathigh2)
    {
        return low2 + (num - low1) * (high2 - low2) / (high1 -low1);
    }
}

usingUnityEngine;
public classEraserGrabAttach : PainterGrabAttach
{
    public override voidProcessFixedUpdate()
    {
        if (grabbedObject)//只有抓住物体后，grabbedObject才不会
{
            grabbedObject.transform.rotation = controllerAttachPoint.transform.rotation *Quaternion.Euler(grabbedSnapHandle.transform.localEulerAngles);
            grabbedObject.transform.position = controllerAttachPoint.transform.position - (grabbedSnapHandle.transform.position -grabbedObject.transform.position);
            float distance = board.GetDistanceFromBoardPlane(transform.position);//黑板檫距离画板的距离
            if (distance > -0.096f)//当黑板檫离画板足够近的时候
{
                float percentOfDistance = Helper.RemapNumberClamped(distance, -0.096f, -0.02f, 0f, 1f);//映射后，得到插值系数
                Quaternion q = Quaternion.FromToRotation(grabbedObject.transform.up, -board.transform.forward);//最终的目的是：黑板擦的transform.up指向-transform.forward
                q *= grabbedObject.transform.rotation;//得到黑板檫达到最终目的时的旋转
                grabbedObject.transform.rotation = Quaternion.Slerp(grabbedObject.transform.rotation, q, percentOfDistance);//通过插值，得到当前黑板檫的旋转
                if (distance > 0.01f)//如果黑板檫穿透了画板，需要进行矫正
{
                    Vector3 pos =board.ProjectPointOnBoardPlane(grabbedObject.transform.position);
                    grabbedObject.transform.position = pos - board.transform.forward * 0.01f;
                }
            }                     
        }
    }
}