用XNA繪製矩形

Question

我正在研究遊戲。我想在出現問題時突出顯示屏幕上的某個位置。

我創建了一個類來爲我做這一點，並找到了一些代碼來繪製矩形：

static private Texture2D CreateRectangle(int width, int height, Color colori) 
{ 
    Texture2D rectangleTexture = new Texture2D(game.GraphicsDevice, width, height, 1, TextureUsage.None, 
    SurfaceFormat.Color);// create the rectangle texture, ,but it will have no color! lets fix that 
    Color[] color = new Color[width * height];//set the color to the amount of pixels in the textures 
    for (int i = 0; i < color.Length; i++)//loop through all the colors setting them to whatever values we want 
    { 
     color[i] = colori; 
    } 
    rectangleTexture.SetData(color);//set the color data on the texture 
    return rectangleTexture;//return the texture 
} 

的問題是，上面的代碼被稱爲每次更新，（60次）， ，並沒有考慮到優化。它需要非常快速（上面的代碼凍結了遊戲，現在只有骨架代碼）。

有什麼建議嗎？

注意：任何新的代碼都會很棒（WireFrame/Fill都可以）。我希望能夠指定顏色。

Answer 1

XNA創建者俱樂部網站上的SafeArea demo有特定的代碼。

您不必每幀創建紋理，只需在LoadContent。該演示代碼的一個非常簡潔的版本：

public class RectangleOverlay : DrawableGameComponent 
{ 
    SpriteBatch spriteBatch; 
    Texture2D dummyTexture; 
    Rectangle dummyRectangle; 
    Color Colori; 

    public RectangleOverlay(Rectangle rect, Color colori, Game game) 
     : base(game) 
    { 
     // Choose a high number, so we will draw on top of other components. 
     DrawOrder = 1000; 
     dummyRectangle = rect; 
     Colori = colori; 
    } 

    protected override void LoadContent() 
    { 
     spriteBatch = new SpriteBatch(GraphicsDevice); 
     dummyTexture = new Texture2D(GraphicsDevice, 1, 1); 
     dummyTexture.SetData(new Color[] { Color.White }); 
    } 

    public override void Draw(GameTime gameTime) 
    { 
     spriteBatch.Begin(); 
     spriteBatch.Draw(dummyTexture, dummyRectangle, Colori); 
     spriteBatch.End(); 
    } 
} 

Answer 2

這可能不是最好的解決方案，但您應該可以使用拉伸的1x1像素紋理來適應矩形。

Answer 3

這就是我做到的。它可能不是最快或最好的解決方案，但它的工作原理。

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

namespace Engine 
{ 
    /// <summary> 
    /// An extended version of the SpriteBatch class that supports line and 
    /// rectangle drawing. 
    /// </summary> 
    public class ExtendedSpriteBatch : SpriteBatch 
    { 
     /// <summary> 
     /// The texture used when drawing rectangles, lines and other 
     /// primitives. This is a 1x1 white texture created at runtime. 
     /// </summary> 
     public Texture2D WhiteTexture { get; protected set; } 

     public ExtendedSpriteBatch(GraphicsDevice graphicsDevice) 
      : base(graphicsDevice) 
     { 
      this.WhiteTexture = new Texture2D(this.GraphicsDevice, 1, 1); 
      this.WhiteTexture.SetData(new Color[] { Color.White }); 
     } 

     /// <summary> 
     /// Draw a line between the two supplied points. 
     /// </summary> 
     /// <param name="start">Starting point.</param> 
     /// <param name="end">End point.</param> 
     /// <param name="color">The draw color.</param> 
     public void DrawLine(Vector2 start, Vector2 end, Color color) 
     { 
      float length = (end - start).Length(); 
      float rotation = (float)Math.Atan2(end.Y - start.Y, end.X - start.X); 
      this.Draw(this.WhiteTexture, start, null, color, rotation, Vector2.Zero, new Vector2(length, 1), SpriteEffects.None, 0); 
     } 

     /// <summary> 
     /// Draw a rectangle. 
     /// </summary> 
     /// <param name="rectangle">The rectangle to draw.</param> 
     /// <param name="color">The draw color.</param> 
     public void DrawRectangle(Rectangle rectangle, Color color) 
     { 
      this.Draw(this.WhiteTexture, new Rectangle(rectangle.Left, rectangle.Top, rectangle.Width, 1), color); 
      this.Draw(this.WhiteTexture, new Rectangle(rectangle.Left, rectangle.Bottom, rectangle.Width, 1), color); 
      this.Draw(this.WhiteTexture, new Rectangle(rectangle.Left, rectangle.Top, 1, rectangle.Height), color); 
      this.Draw(this.WhiteTexture, new Rectangle(rectangle.Right, rectangle.Top, 1, rectangle.Height + 1), color); 
     } 

     /// <summary> 
     /// Fill a rectangle. 
     /// </summary> 
     /// <param name="rectangle">The rectangle to fill.</param> 
     /// <param name="color">The fill color.</param> 
     public void FillRectangle(Rectangle rectangle, Color color) 
     { 
      this.Draw(this.WhiteTexture, rectangle, color); 
     } 
    } 
}