RenderTexture.active

Description

当前处于活动状态的渲染纹理。

所有渲染都将进入处于活动状态的 RenderTexture。 如果处于活动状态的 RenderTexture 为 /null/，则在主窗口中渲染所有内容。

Setting RenderTexture.active is the same as calling Graphics.SetRenderTarget. Typically you change or query the active render texture when implementing custom graphics effects; if all you need is to make a Camera render into a texture then use Camera.targetTexture instead.

当 RenderTexture 处于活动状态时， 将自动创建其硬件渲染上下文（如果尚未创建）。

另请参阅：Graphics.SetRenderTarget。

using UnityEngine;
using System.Collections;

// Get the contents of a RenderTexture into a Texture2D
public class ExampleClass : MonoBehaviour
{
    static public Texture2D GetRTPixels(RenderTexture rt)
    {
        // Remember currently active render texture
        RenderTexture currentActiveRT = RenderTexture.active;

        // Set the supplied RenderTexture as the active one
        RenderTexture.active = rt;

        // Create a new Texture2D and read the RenderTexture image into it
        Texture2D tex = new Texture2D(rt.width, rt.height);
        tex.ReadPixels(new Rect(0, 0, tex.width, tex.height), 0, 0);

        // Restorie previously active render texture
        RenderTexture.active = currentActiveRT;
        return tex;
    }
}