XNA RenderTarget保留内容

Question

我尝试在第一次绘制时将纹理加载到渲染对象中，然后保留内容以在每帧中绘制相同的纹理而不重新创建它。

这是我的代码，但它不起作用，只显示空纹理区域和

RenderTarget2D rTarget = null;
        /// <summary>
        /// This is called when the game should draw itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(GameBackgroundColor);

            SpriteBatch.Begin();

            if (rTarget == null)
            {
                rTarget = new RenderTarget2D(Game.Graphics.GraphicsDevice,
                                           Game.Graphics.GraphicsDevice.PresentationParameters.BackBufferWidth,
                                           Game.Graphics.GraphicsDevice.PresentationParameters.BackBufferHeight,
                                           false,
                                           Game.Graphics.GraphicsDevice.PresentationParameters.BackBufferFormat,
                                           DepthFormat.Depth24, 0, RenderTargetUsage.PreserveContents);

                Game.Graphics.GraphicsDevice.SetRenderTarget(rTarget);

                Game.Graphics.GraphicsDevice.Clear(Color.Black);

                Game.SpriteBatch.Draw(ContentManager.Load<Texture2D>("tiles"), new Rectangle(0, 0, 100, 100), Color.White);

                Game.Graphics.GraphicsDevice.SetRenderTarget(null);
            }

            SpriteBatch.Draw(rTarget, new Rectangle(0, 0,400, 400), Color.White);

            //draw the character
            character.Draw(gameTime);

            SpriteBatch.End();

            base.Draw(gameTime);
        }

这是最终结果：

有谁能解释我做错了什么？

Answer 1

我认为您忘记了渲染目标的Game.SpriteBatch.Begin()和End()。另外我认为您应该SpriteBatch.End()接近Draw(rTarget...方法调用（特别是如果Game.SpriteBatch和SpriteBatch是相同的变量）。

GraphicsDevice.Clear(GameBackgroundColor);
if (rTarget == null)
{
    rTarget = new RenderTarget2D(Game.Graphics.GraphicsDevice,
        Game.Graphics.GraphicsDevice.PresentationParameters.BackBufferWidth,
        Game.Graphics.GraphicsDevice.PresentationParameters.BackBufferHeight,
        false,
        Game.Graphics.GraphicsDevice.PresentationParameters.BackBufferFormat,
        DepthFormat.Depth24, 0, RenderTargetUsage.PreserveContents);

    Game.Graphics.GraphicsDevice.SetRenderTarget(rTarget);
    Game.Graphics.GraphicsDevice.Clear(Color.Black);

    Game.SpriteBatch.Begin();
    Game.SpriteBatch.Draw(ContentManager.Load<Texture2D>("tiles"), new Rectangle(0, 0, 100, 100), Color.White);
    Game.SpriteBatch.End();
    Game.Graphics.GraphicsDevice.SetRenderTarget(null);
}

SpriteBatch.Begin();
SpriteBatch.Draw(rTarget, new Rectangle(0, 0,400, 400), Color.White);

//draw the character
character.Draw(gameTime);

SpriteBatch.End();

base.Draw(gameTime);

Answer 2

找到答案 - 事实证明你需要SpriteBatch.Begin和SpriteBatch.End在每次绘制时都需要渲染到渲染目标。

RenderTarget2D rTarget = null;
/// <summary>
/// This is called when the game should draw itself.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Draw(GameTime gameTime)
{

    if (rTarget == null)
    {
        rTarget = new RenderTarget2D(Game.Graphics.GraphicsDevice,
                                        Game.Graphics.GraphicsDevice.PresentationParameters.BackBufferWidth,
                                        Game.Graphics.GraphicsDevice.PresentationParameters.BackBufferHeight,
                                        false,
                                        Game.Graphics.GraphicsDevice.PresentationParameters.BackBufferFormat,
                                        DepthFormat.Depth24, 0, RenderTargetUsage.PreserveContents);

        Game.Graphics.GraphicsDevice.SetRenderTarget(rTarget);

        Game.Graphics.GraphicsDevice.Clear(Color.Black);

        SpriteBatch.Begin(); //new

        Game.SpriteBatch.Draw(ContentManager.Load<Texture2D>("tiles"), new Rectangle(0, 0, 100, 100), Color.White);

        SpriteBatch.End(); //new

        Game.Graphics.GraphicsDevice.SetRenderTarget(null);
    }

    GraphicsDevice.Clear(GameBackgroundColor);

    SpriteBatch.Begin();

    SpriteBatch.Draw(rTarget, new Rectangle(0, 0,400, 400), Color.White);

    //draw the character
    character.Draw(gameTime);

    SpriteBatch.End();

    base.Draw(gameTime);
}