using UnityEngine;
 
/// <summary>
/// 相機邊緣移動
/// </summary>
[RequireComponent(typeof(Camera))]
public class CameraScreenEdgeMove :MonoBehaviour
{
 
 
 [Header("使用邊緣移動")]
 public bool isUseMoveOnScreenEdge = true;
 
 /// <summary>
 /// 打開調(diào)試
 /// </summary>
 public bool isDebugScreenEdge = true;
 
 //移動速度
 public float moveSpeed = 1f;
 
 /// <summary>
 /// 距離屏幕邊緣多遠就開始移動相機
 /// </summary>
 public int ScreenEdgeSize = 20;
 
 private bool MoveUp;
 private bool MoveDown;
 private bool MoveRight;
 private bool MoveLeft;
 
 private Rect RigthRect;
 private Rect UpRect;
 private Rect DownRect;
 private Rect LeftRect;
 
 private Material mat;
 private Vector3 dir = Vector3.zero;
 
 private void Start()
 {
 CreateLineMaterial();
 }
 
 private void Update()
 {
 if (isUseMoveOnScreenEdge)
 {
  UpRect = new Rect(1f, Screen.height - ScreenEdgeSize, Screen.width, ScreenEdgeSize);
  DownRect = new Rect(1f, 1f, Screen.width, ScreenEdgeSize);
 
  LeftRect = new Rect(1f, 1f, ScreenEdgeSize, Screen.height);
  RigthRect = new Rect(Screen.width - ScreenEdgeSize, 1f, ScreenEdgeSize, Screen.height);
 
 
  MoveUp = (UpRect.Contains(Input.mousePosition));
  MoveDown = (DownRect.Contains(Input.mousePosition));
 
  MoveLeft = (LeftRect.Contains(Input.mousePosition));
  MoveRight = (RigthRect.Contains(Input.mousePosition));
 
  dir.z = MoveUp ? 1 : MoveDown ? -1 : 0;
  dir.x = MoveLeft ? -1 : MoveRight ? 1 : 0;
 
  transform.position = Vector3.Lerp(transform.position, transform.position + dir * moveSpeed,Time.deltaTime);
 
 }
 }
 
 
 void CreateLineMaterial()
 {
 if (!mat)
 {
  Shader shader = Shader.Find("Hidden/Internal-Colored");
  mat = new Material(shader);
  mat.hideFlags = HideFlags.HideAndDontSave;
  mat.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
  mat.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
  mat.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);
  mat.SetInt("_ZWrite", 0);
 }
 }
 
 void OnPostRender()
 {
 if (isUseMoveOnScreenEdge && isDebugScreenEdge)
 {
  DrawRect(UpRect, MoveUp, Color.cyan, Color.red); 
  DrawRect(DownRect, MoveDown, Color.green, Color.red); 
  DrawRect(LeftRect, MoveLeft, Color.yellow, Color.red); 
  DrawRect(RigthRect, MoveRight, Color.blue, Color.red); 
 }
 }
 
 private void DrawRect(Rect rect, bool isMouseEnter, Color normalColor, Color HeighLightColor)
 {
 if (isMouseEnter)
 {
  DrawScreenRect(rect, HeighLightColor);
 }
 else
 {
  DrawScreenRect(rect, normalColor);
 }
 }
 
 private void DrawScreenRect(Rect rect, Color color)
 {
 GL.LoadOrtho();
 GL.Begin(GL.LINES);
 {
  mat.SetPass(0);
  GL.Color(color);
  GL.Vertex3(rect.xMin / Screen.width, rect.yMin / Screen.height, 0);
  GL.Vertex3(rect.xMin / Screen.width, rect.yMax / Screen.height, 0);
 
  GL.Vertex3(rect.xMin / Screen.width, rect.yMax / Screen.height, 0);
  GL.Vertex3(rect.xMax / Screen.width, rect.yMax / Screen.height, 0);
 
  GL.Vertex3(rect.xMax / Screen.width, rect.yMax / Screen.height, 0);
  GL.Vertex3(rect.xMax / Screen.width, rect.yMin / Screen.height, 0);
 
  GL.Vertex3(rect.xMax / Screen.width, rect.yMin / Screen.height, 0);
  GL.Vertex3(rect.xMin / Screen.width, rect.yMin / Screen.height, 0);
  
 }
 GL.End();
 }
 
}