unity中sprite转成texture2d，写一个工具类

可以使用以下代码将Sprite转换成Texture2D：

public static Texture2D SpriteToTexture2D(Sprite sprite) 
{
    Texture2D texture = new Texture2D((int)sprite.rect.width, (int)sprite.rect.height, TextureFormat.RGBA32, false);
    texture.filterMode = FilterMode.Point;

    Color[] spriteColors = sprite.texture.GetPixels((int)sprite.textureRect.x, 
                                                    (int)sprite.textureRect.y, 
                                                    (int)sprite.textureRect.width, 
                                                    (int)sprite.textureRect.height);
    texture.SetPixels(spriteColors);
    texture.Apply();

    return texture;
}

将上述代码放到一个静态类中即可实现一个工具类，用法类似于以下示例：

Sprite sprite = Resources.Load<Sprite>("YourSpriteName");
Texture2D texture = SpriteToTexture2D(sprite);