Unity将RenderTexture转化为Texture2D

RenderTexture和Texture2D同样继承于Texture，两者都可以和Texture之间相互转化，但是两者之间却不能简单的进行强制转换，我们可以通过以下方式将RenderTexture转化为Texture2D：

int width = renderTexture.width;
int height = renderTexture.height;
Texture2D texture2D = new Texture2D(width, height, TextureFormat.ARGB32, false);
RenderTexture.active = renderTexture;
texture2D.ReadPixels(new Rect(0, 0, width, height), 0, 0);
texture2D.Apply();