Silverlight动画编程全解析

# Silverlight动画编程全解析 ## 1. 炸弹拦截游戏实现 ### 1.1 拦截炸弹操作 在炸弹拦截游戏中，用户可通过在炸弹到达画布底部爆炸前点击它来拯救炸弹。由于每个炸弹都是`Bomb`用户控件的独立实例，拦截鼠标点击操作很简单，只需处理`MouseLeftButtonDown`事件即可。当点击炸弹时，会触发以下步骤： 1. 获取相应的炸弹对象，并将其`IsFalling`属性设置为`false`，表示炸弹不再下落。 ```csharp private void bomb_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) { // Get the bomb. Bomb bomb = (Bomb)sender; bomb.IsFalling = false; // Record the bomb's current (animated) position. double currentTop = Canvas.GetTop(bomb); } ``` 2. 找到控制该炸弹动画的故事板并停止它。 ```csharp // Stop the bomb from falling. Storyboard storyboard = storyboards[bomb]; storyboard.Stop(); ``` 3. 复用现有的故事板，添加新的动画，将炸弹移到屏幕外。 ```csharp // Reuse the existing storyboard, but with new animations. // Send the bomb on a new trajectory by animating Canvas.Top // and Canvas.Left. storyboard.Children.Clear(); DoubleAnimation riseAnimation = new DoubleAnimation(); riseAnimation.From = currentTop; riseAnimation.To = 0; riseAnimation.Duration = TimeSpan.FromSeconds(2); Storyboard.SetTarget(riseAnimation, bomb); Storyboard.SetTargetProperty(riseAnimation, new PropertyPath("(Canvas.Top)")); storyboard.Children.Add(riseAnimation); DoubleAnimation slideAnimation = new DoubleAnimation(); double currentLeft = Canvas.GetLeft(bomb); // Throw the bomb off the closest side. if (currentLeft < canvasBackground.ActualWidth / 2) { slideAnimation.To = -100; } else { slideAnimation.To = canvasBackground.ActualWidth + 100; } slideAnimation.Duration = TimeSpan.FromSeconds(1); Storyboard.SetTarget(slideAnimation, bomb); Storyboard.SetTargetProperty(slideAnimation, new PropertyPath("(Canvas.Left)")); storyboard.Children.Add(slideAnimation); // Start the new animation. storyboard.Duration = slideAnimation.Duration; storyboard.Begin(); ``` ### 1.2 炸弹计数与清理 为了跟踪拯救和掉落的炸弹数量，需要对`Storyboard.Completed`事件做出响应。该事件在动画结束时触发，处理逻辑如下： ```csharp private int maxDropped = 5; private int droppedCount = 0; private int savedCount = 0; private void storyboard_Completed(object sender, EventArgs e) { Storyboard completedStoryboard = (Storyboard)sender; Bomb completedBomb = bombs[completedStoryboard]; // Determine if a bomb fell or flew off the Canvas after being clicked. if (completedBomb.IsFalling) { droppedCount++; } else { savedCount++; } // Update the display. lblStatus.Text = String.Format("You have dropped {0} bombs and saved {1}.", droppedCount, savedCount); // Clean up. completedStoryboard.Stop(); canvasBackground.Children.Remove(completedBomb); // Update the tracking collections. storyboards.Remove(completedBomb); bombs.Remove(completedStoryboard); // Check if it's game over. if (droppedCount >= maxDropped) { bombTimer.Stop(); lblStatus.Text += "\r\n\r\nGame over."; // Find all the storyboards that are underway. foreach (KeyValuePair<Bomb, Storyboard> item in storyboards) { Storyboard storyboard = item.Value; Bomb bomb = item.Key; storyboard.Stop(); canvasBackground.Children.Remove(bomb); } // Empty the tracking collections. storyboards.Clear(); bombs.Clear(); // Allow the user to start a new game. cmdStart.IsEnabled = true; } } ``` ### 1.3 游戏优化方向 - **炸弹爆炸效果动画**：可以让炸弹周围的火焰闪烁，或让小块弹片在画布上飞舞。 - **背景动画**：创建一个向上移动的线性渐变，营造运动的感觉，或在两种颜色之间过渡。 - **增加深度**：给炸弹设置不同的大小，较大的炸弹`ZIndex`更高，动画时间更短，使其下落更快，还可让炸弹部分透明。 - **添加音效**：使用适时的音效来突出炸弹爆炸或拯救炸弹的效果。 - **使用动画缓动**：为动画添加缓动函数，使炸弹下落、反弹或摆动更加自然。 - **微调参数**：提供更多可调整的参数，如炸弹的时间、轨迹和频率，增加随机性。 ##