using UnityEngine;
using System.Collections;

public class DrawRect : MonoBehaviour 
{
	public Transform start;
	public Transform end;
	public Color rectColor;
	public Color textColor;

	private Material rectMat = null;//画线的材质 不设定系统会用当前材质画线 结果不可控

	private float shapeSize = 20.0f;
	private float shapeBorder = 3.0f;

	private Transform _spaceShip;
	private Transform _transform;

	void Start()
	{
		rectMat = new Material("Shader \"Lines/Colored Blended\" {" +
		                       "SubShader { Pass { " +
		                       "    Blend SrcAlpha OneMinusSrcAlpha " +
		                       "    ZWrite Off Cull Off Fog { Mode Off } " +
		                       "    BindChannels {" +
		                       "      Bind \"vertex\", vertex Bind \"color\", color }" +
		                       "} } }");//生成画线的材质
		rectMat.hideFlags = HideFlags.HideAndDontSave;
		rectMat.shader.hideFlags = HideFlags.HideAndDontSave;

		_spaceShip = GameManager.Instance.spaceShip;
		_transform = transform;
	}

	void OnGUI()
	{
		rectMat.SetPass(0);

		DrawRadarPoint(_transform, rectColor);

		if(start==null|end==null)
		{
			return;
		}

		if(Camera.main)
		{
			Vector3 cen = Camera.main.WorldToScreenPoint((start.position+end.position)/2);

			if (cen.z>0) {
				//Debug.Log(a+" "+b);
				Draw(cen);
			}
		}


	}

	void DrawRadarPoint(Transform ufo, Color col)
	{
		Vector3 relative = _spaceShip.transform.InverseTransformPoint(ufo.position);
		
		float distance = Mathf.Sqrt( relative.magnitude / 3.0f );
		
		if (distance > 45.0f) {
			return;
		}
		
		float angle = Mathf.Atan2(relative.x, relative.z) - 90.0f * Mathf.Deg2Rad;
		
		Vector2 D = new Vector2( Mathf.Cos(angle), Mathf.Sin(angle) );
		
		D *= distance;
		
		D.x += Screen.width-150;
		D.y += Screen.height-50;
		
		Vector2 dir = new Vector2(0.0f,1.5f);
		Vector2 right = new Vector2(1.5f,0.0f);
		Vector2 A = D + dir * 2.0f;
		Vector2 B = D + right;
		Vector2 C = D - right;

		GL.Color(col);

		GL.Begin(GL.TRIANGLES);
		GL.Vertex3(A.x, A.y, 0);	
		GL.Vertex3(C.x, C.y, 0);	
		GL.Vertex3(B.x, B.y, 0);	
		GL.End();
	}
	
	//渲染2D框
	void Draw(Vector3 cen)
	{	
		
		
		GL.PushMatrix();//保存摄像机变换矩阵
		try {
			GL.LoadPixelMatrix();//设置用屏幕坐标绘图

			// check if OutOfScreen
			if ((cen.x < 0) || (cen.x > Screen.width) || (cen.y < 0) || (cen.y > Screen.height)) {
				Vector2 screenCenter = new Vector2(Screen.width/2, Screen.height/2);
				Vector2 dir = new Vector2(cen.x-screenCenter.x, cen.y-screenCenter.y);
				dir.Normalize();
				cen = polarProject(screenCenter, dir, shapeSize);
				DrawArrow(cen, dir, shapeSize, rectColor, shapeBorder);
			} else {
				DrawFrame(cen, shapeSize, rectColor, shapeBorder);
			}
		} finally {
			GL.PopMatrix();//还原
		}

		if ((cen.y-shapeSize)<=0) {
			DrawDistance(cen.x, cen.y+shapeSize, textColor);
		} else {
			DrawDistance(cen.x, cen.y-shapeSize, textColor);
		}
	}

	Vector2 polarProject(Vector2 screenCenter, Vector2 dir, float size)
	{
		float radius = (Screen.height+Screen.width)*0.5f;

		Vector2 A = screenCenter + dir*(radius*0.5f);
		if (A.x<0)
		{	
			A.x = 0;
		} 
		else 
		{
			if (A.x>Screen.width)
			{
				A.x = Screen.width;
			}
		}
		if (A.y<0)
		{	
			A.y = 0;
		} 
		else 
		{
			if (A.y>Screen.height)
			{
				A.y = Screen.height;
			}
		}
		
		Vector2 D = A - dir*size;
		return D;
	}

	void DrawArrow(Vector2 D, Vector2 dir, float size, Color col, float border)
	{
		/* 
		 *        + A
 		 *      /  \
 		 *    /     \
 		 *  +----+---+
 		 * C     D    B
 		 */
		
		Vector2 right = new Vector2(-dir.y, dir.x);
		right *= size*0.5f;

		Vector2 A = D + dir * size;
		Vector2 B = D + right;
		Vector2 C = D - right;

		GL.Color(col);
		
		GL.Begin(GL.TRIANGLE_STRIP);
			GL.Vertex3(A.x, A.y, 0);	
			GL.Vertex3(C.x, C.y, 0);	
			GL.Vertex3(B.x, B.y, 0);	
		GL.End();
	}

	void DrawFrame(Vector3 cen, float size, Color col, float border)
	{
		/*
		 * +-----------------+
		 * | \             / |
		 * |  +-----------+  |
		 * |  |           |  |
		 * |  |           |  |
		 * |  |           |  |
		 * |  +-----------+  |
		 * | /             \ |
		 * +-----------------+
		 */
		GL.Color(col);

		GL.Begin(GL.TRIANGLE_STRIP);
			GL.Vertex3(cen.x-size+border, cen.y-size+border, 0);
			GL.Vertex3(cen.x-size, cen.y-size, 0);

			GL.Vertex3(cen.x-size+border, cen.y+size-border, 0);
			GL.Vertex3(cen.x-size, cen.y+size, 0);

			GL.Vertex3(cen.x+size-border, cen.y+size-border, 0);
			GL.Vertex3(cen.x+size, cen.y+size, 0);

			GL.Vertex3(cen.x+size-border, cen.y-size+border, 0);
			GL.Vertex3(cen.x+size, cen.y-size, 0);

			GL.Vertex3(cen.x-size+border, cen.y-size+border, 0);
			GL.Vertex3(cen.x-size, cen.y-size, 0);
		GL.End ();
	}
	
	void DrawDistance(float x, float y,Color col)
	{
		if(_spaceShip==null) return;

		float tmp = Vector3.Distance(_transform.position,_spaceShip.position);
		int dis = (int)tmp;
		string str = dis+"km";
		GUI.skin.label.normal.textColor=col;
		Vector2 sz = GUI.skin.label.CalcSize(new GUIContent(str));

		GUI.Label(new Rect(x-sz.x/2,Screen.height-y,sz.x,sz.y),str);
	}
	/*
	void DrawDistance(Vector3 start,Vector3 end,Color col)
	{
		if(spaceShip==null)return;
		start.y=Screen.height-start.y;
		end.y=Screen.height-end.y;
		float tmp = Vector3.Distance(_transform.position,spaceShip.position);
		int dis = (int)tmp;
		string str = dis+"km";
		GUI.skin.label.normal.textColor=col;
		Vector2 sz = GUI.skin.label.CalcSize(new GUIContent(str));
		float x = (start.x+end.x)/2-sz.x/2;
		float y = end.y-sz.y;
		if(y<=0)y=start.y+sz.y;
		GUI.Label(new Rect(x,y,sz.x,sz.y),str);
	}*/
}