介紹

使用 Silverlight 3.0(c#) 開發(fā)一個貪吃蛇游戲

玩法

W/S/A/D 或 ↑/↓/←/→ 控制蛇的移動

截圖

思路

1、貪吃蛇的每一段為 16×16 像素，場景為 640×480 像素，也就說網(wǎng)格為 40×30 個，每個網(wǎng)格的邊長為 16

2、食物的出現(xiàn)位置以及貪吃蛇的運動方向的改變都要在相關(guān)的網(wǎng)格內(nèi)進行

3、貪吃蛇的運動用即時運算的方法計算，當(dāng)貪吃蛇運動到網(wǎng)格內(nèi)（蛇某一段的像素位置%網(wǎng)格的邊長<蛇在某時間單位下的移動偏移量）時做如下工作：修正蛇的位置使其正好在網(wǎng)格內(nèi)，更新蛇的每一段的運動方向，判斷是否吃到了食物、是否發(fā)生了碰撞等

4、貪吃蛇的每一段的運動方向的修改：蛇頭的運動方向根據(jù)用戶的操作改變，蛇的每一段的運動方向設(shè)置為此段的前一段的運動方向（計算時要從尾部向頭部逐段計算）（注：運動方向的改變要在蛇移動到網(wǎng)格內(nèi)時進行。其中如果蛇的某一段移動到了網(wǎng)格內(nèi)，則表明其它各段都在網(wǎng)格內(nèi)）

下面我們看看他的關(guān)鍵代碼都有哪些。

#p#

關(guān)鍵代碼

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Net;  
using System.Windows;  
using System.Windows.Controls;  
using System.Windows.Documents;  
using System.Windows.Input;  
using System.Windows.Media;  
using System.Windows.Media.Animation;  
using System.Windows.Shapes;  
using System.Windows.Media.Imaging;  
using System.Threading;  
namespace YYSnake.Core  
{  
    public partial class Main : UserControl  
    {  
        private int _columns; // 網(wǎng)格列數(shù)  
        private int _rows; // 網(wǎng)格行數(shù)  
        private Dictionary<Body, CellPoint> _bodies = new Dictionary<Body, CellPoint>(); // 貪吃蛇每一段的集合  
        private Dictionary<Bean, CellPoint> _beans = new Dictionary<Bean, CellPoint>(); // 豆的集合  
        private Dictionary<Skin, CellPoint> _skins = new Dictionary<Skin, CellPoint>(); // 蛻下來的皮的集合  
        private List<CellPoint> _emptyCells = new List<CellPoint>(); // 空網(wǎng)格的集合  
        private bool _enabled = false; // 游戲是否運行  
        private double _dt = 0.01; // 多少毫秒計算一次  
        private int _decimals = 1; // 計算小數(shù)時所保留的小數(shù)位  
        private double _speed = 80; // 蛇的運行速度  
        private Direction _moveDirection = Direction.Up; // 蛇的運行方向  
        private int _selfLength = 5; // 蛇的最小長度  
        private int _beansCount = 5; // 豆的***出現(xiàn)數(shù)量  
        private int _ateCapacity = 10; // 食量（超過則蛻皮）  
        private bool _needRaiseAteEvent = false; // 在“蛇頭所處位置進入了網(wǎng)格點區(qū)域內(nèi)”時是否需要觸發(fā)吃豆事件  
        private int _needBeansCount = 0; // 還需要增加的豆的數(shù)量  
        Random _random = new Random();  
        public Main()  
        {  
            InitializeComponent();  
            this.Loaded += new RoutedEventHandler(Main_Loaded);  
        }  
        void Main_Loaded(object sender, RoutedEventArgs e)  
        {  
            this.Width = App.Width; // 640  
            this.Height = App.Height; // 480  
 
            _columns = (int)(Width / App.CellSize); // 40  
            _rows = (int)(Height / App.CellSize); // 30  
 
            // 防止動畫飛出去  
            RectangleGeometry rg = new RectangleGeometry();  
            rg.Rect = new Rect(0, 0, App.Width, App.Height);  
            LayoutRoot.Clip = rg;  
            bg.Width = App.Width;  
            bg.Height = App.Height;  
            ripple.RippleBackground = bg;  
            CompositionTarget.Rendering += new EventHandler(CompositionTarget_Rendering);  
        }  
        /// <summary>  
        /// 初始化  
        /// </summary>  
        public void Init()  
        {  
            _enabled = false;  
            canvasBean.Children.Clear();  
            canvasSnake.Children.Clear();  
            canvasSkin.Children.Clear();  
            _beans.Clear();  
            _bodies.Clear();  
            _skins.Clear();  
            _emptyCells.Clear();  
            for (int i = 0; i < _columns; i++)  
            {  
                for (int j = 0; j < _rows; j++)  
                {  
                    _emptyCells.Add(new CellPoint(i, j));  
                }  
            }  
            _moveDirection = Direction.Up;  
 
            InitSnake();  
        }  
 
        /// <summary>  
        /// 蛇的初始化  
        /// </summary>  
        private void InitSnake()  
        {  
            InitHead();  
 
            for (int i = 0; i < _selfLength - 1; i++)  
                AddTail();  
 
            for (int i = 0; i < _beansCount; i++)  
                AddBean();  
        }  
        /// <summary>  
        /// 蛇頭的初始化  
        /// </summary>  
        private void InitHead()  
        {  
            Body head = new Body(BodyType.Head);  
            head.MoveDirection = _moveDirection;  
            CellPoint point = new CellPoint((int)(_columns / 2), (int)(_rows / 2));  
            head.SetValue(Canvas.LeftProperty, point.X * App.CellSize);  
            head.SetValue(Canvas.TopProperty, point.Y * App.CellSize);  
            _bodies.Add(head, point);  
            canvasSnake.Children.Add(head);  
        }  
        /// <summary>  
        /// 增加一個尾巴  
        /// </summary>  
        private void AddTail()  
        {  
            var prevBody = _bodies.Last().Key;  
            var prevBodyPoint = _bodies.Last().Value;  
            Body tail = new Body(BodyType.Tail);  
            tail.MoveDirection = prevBody.MoveDirection;  
            CellPoint tailPoint = new CellPoint(prevBodyPoint.X, prevBodyPoint.Y);  
            switch (prevBody.MoveDirection)  
            {  
                case Direction.Up:  
                    tail.SetValue(Canvas.LeftProperty, (double)prevBody.GetValue(Canvas.LeftProperty));  
                    tail.SetValue(Canvas.TopProperty, (double)prevBody.GetValue(Canvas.TopProperty) + App.CellSize);  
                    tailPoint.Y++;  
                    break;  
                case Direction.Down:  
                    tail.SetValue(Canvas.LeftProperty, (double)prevBody.GetValue(Canvas.LeftProperty));  
                    tail.SetValue(Canvas.TopProperty, (double)prevBody.GetValue(Canvas.TopProperty) - App.CellSize);  
                    tailPoint.Y--;  
                    break;  
                case Direction.Left:  
                    tail.SetValue(Canvas.LeftProperty, (double)prevBody.GetValue(Canvas.LeftProperty) + App.CellSize);  
                    tail.SetValue(Canvas.TopProperty, (double)prevBody.GetValue(Canvas.TopProperty));  
                    tailPoint.X++;  
                    break;  
                case Direction.Right:  
                    tail.SetValue(Canvas.LeftProperty, (double)prevBody.GetValue(Canvas.LeftProperty) - App.CellSize);  
                    tail.SetValue(Canvas.TopProperty, (double)prevBody.GetValue(Canvas.TopProperty));  
                    tailPoint.X--;  
                    break;  
            }  
 
            tailPoint = CorrectCellPoint(tailPoint);  
            _bodies.Add(tail, tailPoint);  
            canvasSnake.Children.Add(tail);  
        }  
        /// <summary>  
        /// 增加一個豆  
        /// </summary>  
        private void AddBean()  
        {  
            if (_needBeansCount < _beansCount)  
                _needBeansCount++;  
        }  
        private DateTime _prevAddBeanDateTime = DateTime.Now;  
        /// <summary>  
        /// 生成豆  
        /// </summary>  
        void UpdateBean()  
        {  
            if (_needBeansCount > 0 && (DateTime.Now - _prevAddBeanDateTime).TotalSeconds > 3)  
            {  
                List<CellPoint> emptyCells = GetEmptyCells();  
                if (emptyCells.Count == 0)  
                {  
                    GameOver(this, EventArgs.Empty);  
                    return;  
                }  
                CellPoint point = emptyCells[_random.Next(0, emptyCells.Count)];  
                Bean bean = new Bean();  
                bean.SetValue(Canvas.LeftProperty, point.X * App.CellSize);  
                bean.SetValue(Canvas.TopProperty, point.Y * App.CellSize);  
                _beans.Add(bean, point);  
                canvasBean.Children.Add(bean);  
                bean.ani.Completed += delegate  
                {  
                    ripple.ShowRipple(new Point(point.X * App.CellSize + App.CellSize / 2, point.Y * App.CellSize + App.CellSize / 2));  
                    player.PlayDrop();  
                };  
                _needBeansCount--;  
                _prevAddBeanDateTime = DateTime.Now;  
            }  
        }  
        private DateTime _prevDateTime = DateTime.Now;  
        private double _leftoverLength = 0d;  
        void CompositionTarget_Rendering(object sender, EventArgs e)  
        {  
            double length = (DateTime.Now - _prevDateTime).TotalSeconds + _leftoverLength;  
            while (length > _dt)  
            {  
                Update();  
                length -= _dt;  
            }  
            _leftoverLength = length;  
            _prevDateTime = DateTime.Now;  
        }  
        /// <summary>  
        /// 即時計算  
        /// </summary>  
        private void Update()  
        {  
            if (!_enabled)  
                return;  
            double offset = Math.Round(_speed * _dt, _decimals);  
            // 蛇頭所處位置進入了網(wǎng)格點區(qū)域內(nèi)  
            if (Math.Abs(Math.Round((double)_bodies.First().Key.GetValue(Canvas.TopProperty) % App.CellSize, _decimals)) < offset && Math.Abs(Math.Round((double)_bodies.First().Key.GetValue(Canvas.LeftProperty) % App.CellSize, _decimals)) < offset)  
            {  
                UpdateDirection();  
                CorrectPosition();  
                UpdateBodyCell();  
                CheckEat();  
                CheckSkin();  
                CheckCollision();  
                UpdateBean();  
                if (_needRaiseAteEvent)  
                {  
                    Ate(this.Ate, EventArgs.Empty);  
                    _needRaiseAteEvent = false;  
                }  
            }  
            UpdatePosition();  
        }  
        /// <summary>  
        /// 蛻皮  
        /// </summary>  
        private void CheckSkin()  
        {  
            if (_bodies.Count >= _ateCapacity + _selfLength)  
                AddSkin(_ateCapacity);  
        }  
        /// <summary>  
        /// 碰撞檢測  
        /// </summary>  
        private void CheckCollision()  
        {  
            if (_skins.Any(p => p.Value == _bodies.First().Value) || _bodies.Where(p => p.Key.BodyType == BodyType.Tail).Any(p => p.Value == _bodies.First().Value))  
            {  
                _enabled = false;  
                player.PlayOver();  
 
                GameOver(this, EventArgs.Empty);  
            }  
        }  
        /// <summary>  
        /// 吃豆  
        /// </summary>  
        private void CheckEat()  
        {  
            // 是否有被吃的豆  
            var bean = _beans.FirstOrDefault(p => p.Value == _bodies.First().Value).Key;  
            if (bean != null)  
            {  
                _beans.Remove(bean);  
                canvasBean.Children.Remove(bean);  
                player.PlayEat();  
                AddTail();  
                AddBean();  
                _needRaiseAteEvent = true;  
            }  
        }  
        /// <summary>  
        /// 更新蛇的每一段的運動方向  
        /// </summary>  
        private void UpdateDirection()  
        {  
            for (int i = _bodies.Count - 1; i > -1; i--)  
            {  
                if (i == 0)  
                    _bodies.ElementAt(i).Key.MoveDirection = _moveDirection;  
                else 
                    _bodies.ElementAt(i).Key.MoveDirection = _bodies.ElementAt(i - 1).Key.MoveDirection;  
            }  
        }  
        /// <summary>  
        /// 更新蛇的每一段的位置  
        /// </summary>  
        private void UpdatePosition()  
        {  
            double offset = Math.Round(_speed * _dt, _decimals);  
            foreach (var body in _bodies.Keys)  
            {  
                if (body.MoveDirection == Direction.Up)  
                    body.SetValue(Canvas.TopProperty, Math.Round((double)body.GetValue(Canvas.TopProperty) - offset, _decimals));  
                else if (body.MoveDirection == Direction.Down)  
                    body.SetValue(Canvas.TopProperty, Math.Round((double)body.GetValue(Canvas.TopProperty) + offset, _decimals));  
                else if (body.MoveDirection == Direction.Left)  
                    body.SetValue(Canvas.LeftProperty, Math.Round((double)body.GetValue(Canvas.LeftProperty) - offset, _decimals));  
                else if (body.MoveDirection == Direction.Right)  
                    body.SetValue(Canvas.LeftProperty, Math.Round((double)body.GetValue(Canvas.LeftProperty) + offset, _decimals));  
            }  
        }  
        /// <summary>  
        /// 蛻指定數(shù)量的皮  
        /// </summary>  
        private void AddSkin(int count)  
        {  
            player.PlaySkin();  
            while (count > 0)  
            {  
                KeyValuePair<Body, CellPoint> body = _bodies.ElementAt(_bodies.Count - 1);  
                CellPoint skinPoint = body.Value;  
                Skin skin = new Skin();  
                skin.SetValue(Canvas.LeftProperty, skinPoint.X * App.CellSize);  
                skin.SetValue(Canvas.TopProperty, skinPoint.Y * App.CellSize);  
                _skins.Add(skin, skinPoint);  
                canvasSkin.Children.Add(skin);  
                _emptyCells.Remove(skinPoint);  
                canvasSnake.Children.Remove(body.Key);  
                _bodies.Remove(body.Key);  
                count--;  
            }  
        }  
        #region 輔助方法  
        /// <summary>  
        /// 修正指定的位置信息為整數(shù)  
        /// </summary>  
        private int CorrectPosition(double position)  
        {  
            double result;  
            double offset = Math.Round(_speed * _dt, _decimals);  
            double temp = Math.Round(position % App.CellSize, _decimals);  
            if (Math.Abs(temp) < offset)  
                result = Math.Round(position - temp);  
            else 
                result = Math.Round(position - temp) + Math.Sign(temp) * App.CellSize;  
            return (int)result;  
        }  
        /// <summary>  
        /// 修正蛇的每一段的位置為整數(shù)  
        /// </summary>  
        private void CorrectPosition()  
        {  
            foreach (Body body in _bodies.Keys)  
            {  
                double x = CorrectPosition((double)body.GetValue(Canvas.LeftProperty));  
                double y = CorrectPosition((double)body.GetValue(Canvas.TopProperty));  
 
                if (x == App.Width)  
                    x = 0d;  
                else if (x == -App.CellSize)  
                    x = App.Width - App.CellSize;  
                else if (y == App.Height)  
                    y = 0d;  
                else if (y == -App.CellSize)  
                    y = App.Height - App.CellSize;  
                body.SetValue(Canvas.LeftProperty, x);  
                body.SetValue(Canvas.TopProperty, y);  
            }  
        }  
        /// <summary>  
        /// 更新蛇的每一段的網(wǎng)格位置信息  
        /// </summary>  
        private void UpdateBodyCell()  
        {  
            for (int i = 0; i < _bodies.Count; i++)  
            {  
                UpdateBodyCell(_bodies.ElementAt(i).Key);  
            }  
        }  
        /// <summary>  
        /// 更新指定的 Body 的網(wǎng)格位置信息  
        /// </summary>  
        private void UpdateBodyCell(Body body)  
        {  
            CellPoint point = new CellPoint((int)((double)body.GetValue(Canvas.LeftProperty) / App.CellSize), (int)((double)body.GetValue(Canvas.TopProperty) / App.CellSize));  
            if (body.MoveDirection == Direction.Up)  
                point.Y--;  
            else if (body.MoveDirection == Direction.Down)  
                point.Y++;  
            else if (body.MoveDirection == Direction.Left)  
                point.X--;  
            else if (body.MoveDirection == Direction.Right)  
                point.X++;  
 
            point = CorrectCellPoint(point);  
 
            _bodies[body] = point;  
        }  
        /// <summary>  
        /// 修正網(wǎng)格位置  
        /// </summary>  
        private CellPoint CorrectCellPoint(CellPoint point)  
        {  
            if (point.X > _columns - 1)  
                point.X = _columns - point.X;  
            else if (point.X < 0)  
                point.X = point.X + _columns;  
 
            if (point.Y > _rows - 1)  
                point.Y = _rows - point.Y;  
            else if (point.Y < 0)  
                point.Y = point.Y + _rows;  
 
            return point;  
        }  
        /// <summary>  
        /// 獲取空網(wǎng)格集合  
        /// </summary>  
        private List<CellPoint> GetEmptyCells()  
        {  
            List<CellPoint> emptyCells = new List<CellPoint>();  
            List<CellPoint> aroundHeadCells = new List<CellPoint>();  
            CellPoint headPoint = _bodies.First().Value;  
            for (int i = -5; i < 5; i++)  
            {  
                for (int j = -5; j < 5; j++)  
                {  
                    CellPoint point = new CellPoint(headPoint.X + i, headPoint.Y + j);  
                    point = CorrectCellPoint(point);  
 
                    aroundHeadCells.Add(point);  
                }  
            }  
            // skin 的占位情況因為確定了就不變了，所以在 AddSkin() 處計算  
            // 為了以下 LINQ 的可用，需要重寫 CellPoint 的 public override bool Equals(object obj)  
            emptyCells = _emptyCells.Where(p => !_bodies.Select(x => x.Value).Contains(p)).ToList();  
            emptyCells = emptyCells.Where(p => !_beans.Select(x => x.Value).Contains(p)).ToList();  
            emptyCells = emptyCells.Where(p => !aroundHeadCells.Contains(p)).ToList();  
            return emptyCells;  
        }  
        #endregion  
        #region 屬性  
        public Direction MoveDirection  
        {  
            set  
            {  
                Body head = _bodies.First().Key;  
 
                if (head.MoveDirection == Direction.Up && value == Direction.Down)  
                    return;  
                if (head.MoveDirection == Direction.Down && value == Direction.Up)  
                    return;  
                if (head.MoveDirection == Direction.Left && value == Direction.Right)  
                    return;  
                if (head.MoveDirection == Direction.Right && value == Direction.Left)  
                    return;  
                _moveDirection = value;  
            }  
        }  
        public bool Enabled  
        {  
            get { return _enabled; }  
            set { _enabled = value; }  
        }  
        public double Speed  
        {  
            get { return _speed; }  
            set { _speed = value; }  
        }  
        public int AteCapacity  
        {  
            get { return _ateCapacity; }  
            set { _ateCapacity = value; }  
        }  
        #endregion  
        #region 事件 GameOver 和 Ate  
        public event EventHandler GameOver;  
        public event EventHandler Ate;  
        #endregion  
    }  
} 

原文鏈接：http://www.cnblogs.com/webabcd/archive/2009/09/14/1566082.html