如何阻止相机渲染到 RenderTexture？答案

【问题标题】：How do I stop a camera from rendering to a RenderTexture?如何阻止相机渲染到 RenderTexture？
【发布时间】：2020-09-16 22:10:04
【问题描述】：

我的场景中有一个相机，它的目标纹理设置为渲染纹理。我希望该相机将场景渲染到渲染纹理中，然后停止渲染，基本上将帧冻结到渲染纹理中。我怎样才能做到这一点？禁用相机或将其目标纹理设置为 null 似乎只会使渲染纹理看起来不可见。

【问题讨论】：

标签： c# unity3d

【解决方案1】：

如果你想拥有快照功能，你可以这样做

public class SnapshotController : MonoBehaviour
{
    [Tooltip("If you want to capture a specific camera drag it here, otherwise the MainCamera will be used")]
    [SerializeField] private Camera _camera;
 
    [Tooltip("If you have a specific RenderTexture for the snapshot drag it here, otherwise one will be generated on runtime")]   
    [SerializeField] private RenderTexture _renderTexture;
    
    private void Awake()
    {
        if(!_camera) _camera = Camera.main;
    
        if(!_renderTexture)
        {
            _renderTexture = new RenderTexture(Screen.width, Screen.height , 24 , RenderTextureFormat.ARGB32);
            _renderTexture.useMipMap = false;
            _renderTexture.antiAliasing =1;
        }
    }
    
    public void Snapshot(Action<Texture2D> onSnapshotDone)
    {
        StartCoroutine(SnapshotRoutine(onSnapshotDone));
    }
    
    private IEnumerator SnapshotRoutine (Action<Texture2D> onSnapshotDone)
    {
        // this also captures gui, remove if you don't wanna capture gui
        yield return new WaitForEndOfFrame(); 
               
        // If RenderTexture.active is set any rendering goes into this RenderTexture
        // instead of the GameView
        RenderTexture.active = _renderTexture;
        _camera.targetTexture = _renderTexture;
               
        // renders into the renderTexture
        _camera.Render();
     
        // Create a new Texture2D        
        var result = new Texture2D(Screen.width,Screen.height,TextureFormat.ARGB32,false);
        // copies the pixels into the Texture2D          
        result.ReadPixels(new Rect(0,0,Screen.width,Screen.height),0,0,false);
        result.Apply();
       
        // reset the RenderTexture.active so nothing else is rendered into our RenderTexture      
        RenderTexture.active = null;
        _camera.targetTexture = null;
    
        // Invoke the callback with the resulting snapshot Texture
        onSnapshotDone?.Invoke(result);
    }
}

然后你会像这样使用它

// Pass in a callback telling the routine what to do when the snapshot is ready
xy.GetComponent<SnapshotController>(). Snapshot(HandleNewSnapshotTexture);

...

private void HandleNewSnapshotTexture (Texture2D texture)
{
    var material = GetComponent<Renderer>().material;

    // IMPORTANT! Textures are not automatically GC collected. 
    // So in order to not allocate more and more memory consider actively destroying
    // a texture as soon as you don't need it anymore
    if(material.mainTexture) Destroy (material.mainTexture);     

    material.mainTexture = texture;
}

【讨论】：

【解决方案2】：

您可以在开始冻结的帧中拍摄实际渲染纹理的快照，获取此图像数据并将渲染纹理替换为应用此冻结图像的实际纹理。

【讨论】：