八、生成新的单节蛇身
我们这里先说说游戏小原理好了，游戏运行后，通过计时器事件不断生成新的单节蛇身类SnakeNode，添加到List中的0位置，原来的蛇头变成了第二节。该节新蛇头的坐标通过蛇头前进方向Direct进行判断，即如果原蛇头往左运行，则新蛇头在原蛇头位置的左一格生成，其他方向以此类推。最后将该节添加到SnakeNodes列表中，并将相应图形添加到游戏区。
private void GenNewSnakeNode() { SnakeNode snakeNode = null; switch (Direct) { case Direction.UP: snakeNode = new SnakeNode(new Point(SnakeNodes[SnakeHead]._pos.X, SnakeNodes[SnakeHead]._pos.Y - 1)); break; case Direction.DOWN: snakeNode = new SnakeNode(new Point(SnakeNodes[SnakeHead]._pos.X, SnakeNodes[SnakeHead]._pos.Y + 1)); break; case Direction.LEFT: snakeNode = new SnakeNode(new Point(SnakeNodes[SnakeHead]._pos.X - 1, SnakeNodes[SnakeHead]._pos.Y)); break; case Direction.RIGHT: snakeNode = new SnakeNode(new Point(SnakeNodes[SnakeHead]._pos.X + 1, SnakeNodes[SnakeHead]._pos.Y)); break; } if (snakeNode != null) { SnakeNodes.Insert(0, snakeNode); myCanvas.Children.Add(SnakeNodes[0]._rect); } }
九、随机水果位置
注意该新位置不得与蛇身任何一节重叠，如果重叠则另外生成新位置，直到成功为止。
private Point SetFruitToRandomPos() { bool flag = true; Point pos = new Point(); while (flag) { flag = false; pos = new Point(rnd.Next(0, CellWidth - 1), rnd.Next(0, CellHeight - 1)); foreach (var node in SnakeNodes) { if (pos.X == node._pos.X && pos.Y == node._pos.Y) { flag = true; break; } } } return pos; }
十、碰撞检测（蛇头与水果）
因为只有蛇头会最先触碰到水果，所以只需判断蛇头坐标与水果坐标是否相同即可。如果撞到水果，则将水果随机生成新位置；如果没有碰到，则删除蛇尾一节（因为之后会通过计时器会生成新一节蛇头，这样就会保存蛇身长度，感觉位置前进了一格）。
private void CheckCollision() { if (SnakeNodes[SnakeHead]._pos.X == fruit._pos.X && SnakeNodes[SnakeHead]._pos.Y == fruit._pos.Y) { fruit.SetPostion(SetFruitToRandomPos()); } else { if (myCanvas.Children.Contains(SnakeNodes[SnakeNodes.Count - 1]._rect)) myCanvas.Children.Remove(SnakeNodes[SnakeNodes.Count - 1]._rect); SnakeNodes.RemoveAt(SnakeNodes.Count - 1); } }
十一、判断是否游戏结束
很简单，看看蛇头是否触碰游戏区四边或蛇身的任何一节，如果是则返回true。
注意蛇身循环是从1开始的，如果从0开始你知道会出现什么情况。
private bool IsGameOver() { if (SnakeNodes[SnakeHead]._pos.X == -1 || SnakeNodes[SnakeHead]._pos.X == CellWidth || SnakeNodes[SnakeHead]._pos.Y == -1 || SnakeNodes[SnakeHead]._pos.Y == CellHeight) { return true; } foreach (var node in SnakeNodes) { if (node == SnakeNodes[SnakeHead]) continue; if (node._pos.X == SnakeNodes[SnakeHead]._pos.X && node._pos.Y == SnakeNodes[SnakeHead]._pos.Y) { return true; } } return false; }
十三、删除游戏区的所有蛇身节
这个会在重新开始游戏时使用到：
private void RemoveSnakeNodeAll() { for (int i = 0; i < SnakeNodes.Count; i++) { if (myCanvas.Children.Contains(SnakeNodes[i]._rect)) { myCanvas.Children.Remove(SnakeNodes[i]._rect); } } }
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顺便再来一发删除游戏区的水果：
private void RemoveFruit() { if (fruit == null) { return; } if (myCanvas.Children.Contains(fruit._ellipse)) { myCanvas.Children.Remove(fruit._ellipse); } }
十四、按键操作
通过方向键，设置Direct值即可。
private void MyCanvas_PreviewKeyDown(object sender, KeyEventArgs e) { switch (e.Key) { case Key.Left: if (Direct != Direction.RIGHT) { Direct = Direction.LEFT; } break; case Key.Right: if (Direct != Direction.LEFT) { Direct = Direction.RIGHT; } break; case Key.Up: if (Direct != Direction.DOWN) { Direct = Direction.UP; } break; case Key.Down: if (Direct != Direction.UP) { Direct = Direction.DOWN; } break; case Key.Escape: Application.Current.Shutdown(); break; case Key.Space: if (CurrGameState == GameState.NONE) return; if (CurrGameState == GameState.PAUSE) { CurrGameState = GameState.GAMEING; timer.Start(); MenuControl_Pause.Header = "暂停"; } else if (CurrGameState == GameState.GAMEING) { CurrGameState = GameState.PAUSE; timer.Stop(); MenuControl_Pause.Header = "继续"; } break; } }
十四、定义开始游戏方法
先删除界面中的蛇身和水果（保留底部暗格），随机位置生成水果和三节蛇身。
private void StartGame() { RemoveSnakeNodeAll(); RemoveFruit(); int startX = rnd.Next(5, CellWidth - 6); int startY = rnd.Next(5, CellHeight - 6); Direct = Direction.RIGHT; fruit = new Fruit(SetFruitToRandomPos(), myCanvas); SnakeNodes = new List<SnakeNode>(); SnakeNodes.Add(new SnakeNode(new Point(startX, startY))); GenNewSnakeNode(); GenNewSnakeNode(); }
十五、开始游戏菜单
调用StartGame()方法，并设定计时器开始。
private void MenuFile_NewGame_Click(object sender, RoutedEventArgs e) { StartGame(); timer.Start(); CurrGameState = GameState.GAMEING; MenuControl_Pause.Header = "暂停"; }
十六、暂停与继续
直接上代码，没有要说的了。
private void MenuControl_Pause_Click(object sender, RoutedEventArgs e) { if (CurrGameState == GameState.GAMEING) { CurrGameState = GameState.PAUSE; timer.Stop(); MenuControl_Pause.Header = "继续"; } else if (CurrGameState == GameState.PAUSE) { CurrGameState = GameState.GAMEING; timer.Start(); MenuControl_Pause.Header = "暂停"; } }
十七、退出游戏
private void MenuFile_Exit_Click(object sender, RoutedEventArgs e) { Application.Current.Shutdown(); }
十八、其他菜单功能
自己实现好了
private void MenuHelp_About_Click(object sender, RoutedEventArgs e) { }
