using UnityEngine;
using System.Collections;

[RequireComponent(typeof(Camera))]
public class ShowSelection : MonoBehaviour
{
    private Camera myCamera;
    public int Iterations = 3;
    public float Spread = 0.7f;
    public Color OutLineColor = new Color(0.133f, 1, 0, 1);
    public Camera outterLineCamera;

    public Shader compositeShader;
    Material m_CompositeMaterial = null;

    private int originPixelWidth;
    private int originPixelHeight;

    protected Material compositeMaterial
    {
        get
        {
            if (m_CompositeMaterial == null)
            {
                m_CompositeMaterial = new Material(compositeShader);
                m_CompositeMaterial.hideFlags = HideFlags.HideAndDontSave;
            }
            return m_CompositeMaterial;
        }
    }

    public Shader blurShader;
    Material m_BlurMaterial = null;
    protected Material blurMaterial
    {
        get
        {
            if (m_BlurMaterial == null)
            {
                m_BlurMaterial = new Material(blurShader);
                m_BlurMaterial.hideFlags = HideFlags.HideAndDontSave;
            }
            return m_BlurMaterial;
        }
    }


    public Shader cutoffShader;
    Material m_cutoffMaterial = null;
    protected Material cutoffMaterial
    {
        get
        {
            if (m_cutoffMaterial == null)
            {
                m_cutoffMaterial = new Material(cutoffShader);
                m_cutoffMaterial.hideFlags = HideFlags.HideAndDontSave;
            }
            return m_cutoffMaterial;
        }
    }

    private Material m_outterLineMat = null;
    public Shader HighLightedShader;
    protected Material outterLineMat
    {
        get
        {
            if (m_outterLineMat == null)
            {
                //m_outterLineMat = new Material("Shader\"Hidden/SolidBody1\"{SubShader{Pass{Color(" +
                //    outterColor.r + "," + outterColor.g + "," + outterColor.b + "," + outterColor.a + ")}}}");

                Shader.SetGlobalColor("highLightColor",OutLineColor);
                m_outterLineMat = new Material(HighLightedShader);
                m_outterLineMat.hideFlags = HideFlags.HideAndDontSave;
                //m_outterLineMat.shader.hideFlags = HideFlags.HideAndDontSave;
            }
            return m_outterLineMat;
        }
    }

    private RenderTexture outterLineTexture = null;


    void Start()
    {
        if (!SystemInfo.supportsImageEffects)
        {//判断显卡是否支持图形后处理效果
            enabled = false;
            return;
        }
        if (!blurMaterial.shader.isSupported)//判断显卡是否支持此shader
            enabled = false;
        if (!compositeMaterial.shader.isSupported)//判断显卡是否支持此shader
            enabled = false;
        if (!cutoffMaterial.shader.isSupported)//判断显卡是否支持此shader
            enabled = false;
        if (!outterLineMat.shader.isSupported)//判断显卡是否支持此shader
            enabled = false;

        myCamera = GetComponent<Camera>();

        if (!outterLineTexture)
        {
            outterLineTexture = new RenderTexture((int)myCamera.pixelWidth, (int)myCamera.pixelHeight, 16);
            outterLineTexture.hideFlags = HideFlags.DontSave;
        }

        originPixelWidth = (int)myCamera.pixelWidth;
        originPixelHeight = (int)myCamera.pixelHeight;
    }

    void Update()
    {
        if (outterLineTexture)
        {
            int nowPixWidth = (int)myCamera.pixelWidth;
            int nowPixHeight = (int)myCamera.pixelHeight;
            if (originPixelWidth == nowPixWidth && originPixelHeight == nowPixHeight)
            {
                return;
            }
            if (originPixelWidth != nowPixWidth || originPixelHeight != nowPixHeight)
            {
                outterLineTexture = new RenderTexture(nowPixWidth, nowPixHeight, 16);
                originPixelWidth = nowPixWidth;
                originPixelHeight = nowPixHeight;
            }
        }
    }

    void OnDisable()
    {
        if (outterLineTexture)
        {
            outterLineCamera.targetTexture = null;
            DestroyImmediate(outterLineTexture);
            outterLineTexture = null;
        }
        if (m_CompositeMaterial)
        {
            DestroyImmediate(m_CompositeMaterial);
        }
        if (m_BlurMaterial)
        {
            DestroyImmediate(m_BlurMaterial);
        }
        if (m_outterLineMat)
        {
            DestroyImmediate(m_outterLineMat);
        }
    }

    public void FourTapCone(RenderTexture source, RenderTexture dest, int iteration)
    {
        float off = 0.5f + iteration * Spread;
        Graphics.BlitMultiTap(source, dest, blurMaterial,
            new Vector2(off, off),
            new Vector2(-off, off),
            new Vector2(off, -off),
            new Vector2(-off, -off)
        );
    }

    void OnPreRender()
    {
        outterLineCamera.targetTexture = outterLineTexture;
        outterLineCamera.RenderWithShader(outterLineMat.shader, "");
    }

    void OnRenderImage(RenderTexture source, RenderTexture destination)
    {
        Iterations = Mathf.Clamp(Iterations, 0, 15);
        Spread = Mathf.Clamp(Spread, 0.5f, 6.0f);

        RenderTexture buffer = RenderTexture.GetTemporary(outterLineTexture.width, outterLineTexture.height, 0);
        RenderTexture buffer2 = RenderTexture.GetTemporary(outterLineTexture.width, outterLineTexture.height, 0);

        Graphics.Blit(outterLineTexture, buffer);

        bool oddEven = true;
        for (int i = 0; i < Iterations; i++)
        {
            if (oddEven)
                FourTapCone(buffer, buffer2, i);
            else
                FourTapCone(buffer2, buffer, i);
            oddEven = !oddEven;
        }
        Graphics.Blit(source, destination);
        if (oddEven)
        {
            Graphics.Blit(outterLineTexture, buffer, cutoffMaterial);
            Graphics.Blit(buffer, destination, compositeMaterial);
        }
        else
        {
            Graphics.Blit(outterLineTexture, buffer2, cutoffMaterial);
            Graphics.Blit(buffer2, destination, compositeMaterial);
        }

        RenderTexture.ReleaseTemporary(buffer);
        RenderTexture.ReleaseTemporary(buffer2);
    }
}