After Writing to a RenderTarget, How to Efficiently Clone the Output?

Question

XNA noob here, learning every day. I just worked out how to composite multiple textures into one using a RenderTarget2D. However, while I can use the RenderTarget2D as a Te

Answer 1

Replace

Texture2D  mergedTexture = new Texture2D(_device, width, height);
Color[]    content       = new Color[width * height];
buffer.GetData(content);
mergedTexture.SetData(content);
return mergedTexture;

with

return buffer;

Because RenderTarget2D extends Texture2D you will just get Texture2D class data returned. Also in case you are interested here's a class i made for building my GUI library's widgets out of multiple textures. In case you need to be doing this sort of thing a lot.

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using System.IO;

namespace Voodo.Utils {

    /// 

    /// 
    /// 
    public class TextureBaker {

        private readonly SpriteBatch _batch;
        private readonly RenderTarget2D _renderTarget;
        private readonly GraphicsDevice _graphicsDevice;

        /// 

        /// 
        /// 
        public Rectangle Bounds {
            get { return _renderTarget.Bounds; }
        }

        /// 

        /// 
        /// 
        /// 
        /// 
        public TextureBaker(GraphicsDevice graphicsDevice, Vector2 size) {

            _graphicsDevice = graphicsDevice;

            _batch = new SpriteBatch(_graphicsDevice);
            _renderTarget = new RenderTarget2D(
                _graphicsDevice, 
                (int)size.X, 
                (int)size.Y);

            _graphicsDevice.SetRenderTarget(_renderTarget);

            _graphicsDevice.Clear(Color.Transparent);

            _batch.Begin(
                SpriteSortMode.Immediate, 
                BlendState.AlphaBlend, 
                SamplerState.LinearClamp,
                DepthStencilState.Default, 
                RasterizerState.CullNone);
        }

        #region Texture2D baking

        /// 

        /// 
        /// 
        /// 
        public void BakeTexture(Texture2D texture) {

            _batch.Draw(
                texture,
                new Rectangle(0, 0, Bounds.Width, Bounds.Height), 
                Color.White);
        }

        /// 

        /// 
        /// 
        /// 
        /// 
        public void BakeTexture(Texture2D texture, Rectangle destination) {

            _batch.Draw(
                texture,
                destination,
                Color.White);
        }        

        /// 

        /// 
        /// 
        /// 
        /// 
        /// 
        public void BakeTexture(Texture2D texture, Rectangle destination, Rectangle source) {

            _batch.Draw(
                texture,
                destination,
                source,
                Color.White);
        }

        /// 

        /// 
        /// 
        /// 
        /// 
        /// 
        public void BakeTexture(Texture2D texture, System.Drawing.RotateFlipType sourceModification, Rectangle destination) {

            Stream sourceBuffer = new MemoryStream();
            texture.SaveAsPng(sourceBuffer, texture.Width, texture.Height);

            System.Drawing.Image sourceImage = System.Drawing.Image.FromStream(sourceBuffer);

            sourceBuffer = new MemoryStream();
            sourceImage.RotateFlip(sourceModification);
            sourceImage.Save(sourceBuffer, System.Drawing.Imaging.ImageFormat.Png);                       

            _batch.Draw(
                Texture2D.FromStream(_graphicsDevice, sourceBuffer),
                destination,
                Color.White);
        }

        /// 

        /// 
        /// 
        /// 
        /// 
        /// 
        /// 
        public void BakeTexture(Texture2D texture, System.Drawing.RotateFlipType sourceModification, Rectangle destination, Rectangle source) {

            Stream sourceBuffer = new MemoryStream();
            texture.SaveAsPng(sourceBuffer, texture.Width, texture.Height);

            System.Drawing.Image sourceImage = System.Drawing.Image.FromStream(sourceBuffer);

            sourceBuffer = new MemoryStream();
            sourceImage.RotateFlip(sourceModification);
            sourceImage.Save(sourceBuffer, System.Drawing.Imaging.ImageFormat.Png);

            _batch.Draw(
                Texture2D.FromStream(_graphicsDevice, sourceBuffer),
                destination,
                source,
                Color.White);
        }

        #endregion

        #region SpriteFont baking

        /// 

        /// 
        /// 
        /// 
        /// 
        /// 
        /// 
        public void BakeText(SpriteFont font, string text, Vector2 location, Color textColor) {

            _batch.DrawString(font, text, location, textColor);
        }

        /// 

        /// 
        /// 
        /// 
        /// 
        /// 
        public void BakeTextCentered(SpriteFont font, string text, Vector2 location, Color textColor) {

            var shifted = new Vector2 {
                X = location.X - font.MeasureString(text).X / 2,
                Y = location.Y - font.MeasureString(text).Y / 2
            };

            _batch.DrawString(font, text, shifted, textColor);
        }

        #endregion

        /// 

        /// 
        /// 
        /// 
        public Texture2D GetTexture() {

            _batch.End();
            _graphicsDevice.SetRenderTarget(null);

            return _renderTarget;
        }
    }
}