unity 利用linrenderer模仿画笔写字代码

以下是基于 Unity 的 LineRenderer 组件模拟画笔书写的示例代码：

public class Pen : MonoBehaviour
{
    public LineRenderer lineRenderer;
    public float lineWidth = 0.1f;
    public Color lineColor = Color.black;
    public float drawDistanceThreshold = 0.1f;

    private List<Vector3> _points = new List<Vector3>();
    private float _drawDistance = 0f;

    void Start()
    {
        lineRenderer.startWidth = lineWidth;
        lineRenderer.endWidth = lineWidth;
        lineRenderer.startColor = lineColor;
        lineRenderer.endColor = lineColor;
    }

    void Update()
    {
        if (Input.GetMouseButton(0))
        {
            Vector3 point = Camera.main.ScreenToWorldPoint(Input.mousePosition);
            point.z = 0f;

            if (_points.Count == 0)
            {
                _points.Add(point);
                lineRenderer.positionCount = _points.Count;
                lineRenderer.SetPosition(0, point);
            }
            else
            {
                Vector3 lastPoint = _points[_points.Count - 1];
                _drawDistance += Vector3.Distance(point, lastPoint);

                if (_drawDistance >= drawDistanceThreshold)
                {
                    _points.Add(point);
                    lineRenderer.positionCount = _points.Count;
                    lineRenderer.SetPosition(_points.Count - 1, point);
                    _drawDistance = 0f;
                }
            }
        }
        else
        {
            _points.Clear();
            _drawDistance = 0f;
            lineRenderer.positionCount = 0;
        }
    }
}

这个代码使用 LineRenderer 组件来绘制画笔轨迹，每次鼠标移动时，计算当前点与上一个点之间的距离，只有距离超过一定阈值时才添加新的顶点，以此模拟画笔书写的效果。