[Unity基礎]RenderTexture

參考鏈接：

https://www.cnblogs.com/Jimm/p/5951362.html

 

一.相關API

1.Texture2D.ReadPixels

從RenderTexture.active中復制像素，以左下角為原點。

2.MonoBehaviour.OnPostRender

當相機渲染完所有物體就會調用該方法，並且只有當這個腳本掛在相機時才會調用。

 

二.測試

新建一個場景，新建一個camera和一個go，把go設置為一個單獨的層，讓camera單獨照這個層，主camera不要照這個層。調整camera的深度和targetTexture。

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using System.IO;

public class TestRenderTexture : MonoBehaviour {

    public Camera camera;
    public RawImage rawImage;
    bool isScreenShot = false;

    void Update()
    {
        //將鏡頭的畫面保存到本地
        if (Input.GetKeyDown(KeyCode.Q))
        {
            Texture2D tex = RenderTexture2Texture2D(camera.targetTexture);

            //展示
            rawImage.texture = tex;

            //保存到本地
            byte[] bytes = tex.EncodeToPNG();
            File.WriteAllBytes(Application.dataPath + "/RenderTexture/Test.png", bytes);
            UnityEditor.AssetDatabase.Refresh();
        }

        //屏幕截圖(方法1)
        if (Input.GetKeyDown(KeyCode.W))
        {
            StartCoroutine(ScreenShotIEnumerator());
        }

        //屏幕截圖(方法2)
        if (Input.GetKeyDown(KeyCode.E))
        {
            isScreenShot = true;
        }
    }

    public IEnumerator ScreenShotIEnumerator()
    {
        yield return new WaitForEndOfFrame();
        rawImage.texture = ScreenShot();
    }

    private void OnPostRender()
    {
        //Debug.Log("OnPostRender");
        if (isScreenShot)
        {
            isScreenShot = false;
            rawImage.texture = ScreenShot();
        }
    }

    //屏幕截圖
    public Texture2D ScreenShot()
    {
        Texture2D tex = new Texture2D(Screen.width, Screen.height, TextureFormat.ARGB32, false);
        tex.ReadPixels(new Rect(0, 0, Screen.width, Screen.height), 0, 0);
        tex.Apply();
        return tex;
    }

    //RenderTexture轉Texture2D
    public Texture2D RenderTexture2Texture2D(RenderTexture rt)
    {
        RenderTexture preRT = RenderTexture.active;
        RenderTexture.active = rt;
        Texture2D tex = new Texture2D(rt.width, rt.height, TextureFormat.ARGB32, false);
        tex.ReadPixels(new Rect(0, 0, rt.width, rt.height), 0, 0);
        tex.Apply();
        RenderTexture.active = preRT;
        return tex;
    }
}