XNA框架：操縱屏幕亮度

Question

我正在爲XNA框架的遊戲項目工作。

我正在使用OptionsMenuScreen類來向用戶顯示不同的遊戲選項/設置。

我在屏幕上增加了兩個UP和DOWN按鈕（Texture2D），以增加或減少屏幕的亮度。

我無法找到我需要用來操縱屏幕亮度的邏輯。

如果你能請我指出正確的方向，我將非常感激。

下面是相關代碼：

---

class OptionsMenuScreen : MenuScreen 
{ 
    SpriteBatch spriteBatch; 

    MenuEntry brightness; 
    Texture2D brightnessUp; 
    Texture2D brightnessDown; 

    ContentManager contentManager; 

    public OptionsMenuScreen() : base("Options") 
    { 
     brightness = new MenuEntry("Brightness"); 
     MenuEntries.Add(brightness); 
    } 

    public override void LoadContent() 
    { 
     if (contentManager == null) 
     { 
      contentManager = new ContentManager(ScreenManager.Game.Services, "Content"); 
     } 

     brightnessUp = contentManager.Load<Texture2D>("handup"); 
     brightnessDown = contentManager.Load<Texture2D>("handdown"); 
    } 

    public override void Draw(GameTime gameTime) 
    { 
     spriteBatch = ScreenManager.SpriteBatch; 

     var brightnessDownPosition = 
      new Vector2(brightness.Position.X - 50, brightness.Position.Y - 12); 

     var brightnessUpPosition = 
      new Vector2(brightness.Position.X 
       + brightness.GetWidth(this) + 8, brightness.Position.Y - 12); 

     spriteBatch.Begin(); 

     spriteBatch.Draw(brightnessDown, 
      new Rectangle((int)brightnessDownPosition.X, (int)brightnessDownPosition.Y, 
       30, 30), Color.White); 

     spriteBatch.Draw(brightnessUp, 
      new Rectangle((int)brightnessUpPosition.X, (int)brightnessUpPosition.Y, 
       30, 30), Color.White); 

     spriteBatch.End(); 

     base.Draw(gameTime); 
    } 

    public override void Update(GameTime gameTime, bool otherScreenHasFocus, bool coveredByOtherScreen) 
    { 
     base.Update(gameTime, otherScreenHasFocus, coveredByOtherScreen); 

     foreach (TouchLocation t in TouchPanel.GetState()) 
     { 
      if (t.Position.X >= brightnessDown.Bounds.Left 
       && t.Position.X <= brightnessDown.Bounds.Right 
       && t.Position.Y >= brightnessDown.Bounds.Top 
       && t.Position.X <= brightnessDown.Bounds.Bottom) 
      { 
       // What should I do here? 
      } 
      else if (t.Position.X >= brightnessUp.Bounds.Left 
       && t.Position.X <= brightnessUp.Bounds.Right 
       && t.Position.Y >= brightnessUp.Bounds.Top 
       && t.Position.X <= brightnessUp.Bounds.Bottom) 
      { 
       // What should I do here? 
      } 
     } 
    } 
} 

---

非常感謝您就這個:)

Answer 1

According to this thread，有幾種方法，你可以去了解它：

• 使用GraphicsDevice.SetGammaRamp(...)
• 使用黑色紋理和Alpha透明度
• 使用像素着色器

第一種選擇是調節上的紋理的所有對象的材料和/或燈在場景

每像素顏色重新計算最簡單，但有一些缺點（在設置時會產生醜陋的圖形效果 - 主要影響選項菜單），並不總是受支持。

您可以使用SupportsFullScreenGamma和CanCalibrateGamma來確定它是否受支持，如果不支持則回退到其他方法。

編輯

在Windows Phone 7，some of these options might not be available to you。

該網站（目前打破，但如果谷歌它，你可以找到一個緩存副本）建議您使用alpha混合方式全屏四，與這些特定的混合模式：

Brightness: source = ZERO, dest = SOURCECOLOR 
Contrast: source = DESTCOLOR, dest = SOURCECOLOR 

下面是一些代碼（從該文章中被盜）：

// In your game class: 

Texture2D whiteTexture; 

// In LoadContent: 

whiteTexture = new Texture2D(GraphicsDevice, 1, 1); 
whiteTexture.SetData<Color>(new Color[] { Color.White }); 

// In the appropriate class (the game class? not sure...): 

int brightness; 
int contrast; 

BlendState brightnessBlend; 
BlendState contrastBlend; 

// In Initialize: 

brightness = 255; 
contrast = 128; 

brightnessBlend = new BlendState(); 
brightnessBlend.ColorSourceBlend = brightnessBlend.AlphaSourceBlend = Blend.Zero; 
brightnessBlend.ColorDestinationBlend = brightnessBlend.AlphaDestinationBlend = Blend.SourceColor; 

contrastBlend = new BlendState(); 
contrastBlend.ColorSourceBlend = contrastBlend.AlphaSourceBlend = Blend.DestinationColor; 
contrastBlend.ColorDestinationBlend = contrastBlend.AlphaDestinationBlend = Blend.SourceColor; 

// In Draw: 

spriteBatch.Begin(SpriteSortMode.Immediate, brightnessBlend); 
spriteBatch.Draw(whiteTexture, new Rectangle(0, 0, 480, 800), new Color (brightness, brightness, brightness, 255)); 
spriteBatch.End(); 

spriteBatch.Begin(SpriteSortMode.Immediate, contrastBlend); 
spriteBatch.Draw(whiteTexture, new Rectangle(0, 0, 480, 800), new Color(contrast, contrast, contrast, 255)); 
spriteBatch.End(); 

GraphicsDevice.BlendState = BlendState.Opaque;