一步一步学做游戏第五回：熊碰撞蘑菇处理_H5之家

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一步一步学做游戏第五回：熊碰撞蘑菇处理

字号+ 作者：admin 来源： 2014-11-16 21:26 我要评论( )

第五回主要讲熊碰到蘑菇之后向上反弹的效果预期达到的效果： http://www.html5china.com/html5games/mogu/index4.html 一、由于碰撞的地方比较多，所以定义一个通用的判断2个物体是否碰撞的函

第五回主要讲熊碰到http://www.html5china.com/html5games/mogu/index4.html

一、由于碰撞的地方比较多，所以定义一个通用的判断2个

JavaScript Code复制内容到剪贴板

//方法用途：检测2个物体是否碰撞

//参数object1：物体1

//参数object1：物体2

//参数overlap：可重叠的区域值

//返回布尔值：碰撞返回true，不碰撞返回false

function CheckIntersect(object1, object2, overlap)

{

    //    x-轴                      x-轴

    //  A1------>B1 C1              A2------>B2 C2

    //  +--------+   ^              +--------+   ^

    //  | object1|   | y-轴         | object2|   | y-轴

    //  |        |   |              |        |   |

    //  +--------+  D1              +--------+  D2

    //  看图可知两物体各4个点的位置

    A1 = object1.x + overlap;

    B1 = object1.x + object1.image.width - overlap;

    C1 = object1.y + overlap;

    D1 = object1.y + object1.image.height - overlap;



    A2 = object2.x + overlap;

    B2 = object2.x + object2.image.width - overlap;

    C2 = object2.y + overlap;

    D2 = object2.y + object2.image.width - overlap;



    //假如他们在x-轴重叠

    if(A1 > A2 && A1 < B2

       || B1 > A2 && B1 < B2)

    {

        //判断y-轴重叠

        if(C1 > C2 && C1 < D1

       || D1 > C2 && D1 < D2)

        {

            //碰撞

            return true;

        }

    }

    return false;

}

二、
JavaScript Code复制内容到剪贴板

//动物碰撞蘑菇

function HasAnimalHitMushroom()

{

    //假如碰撞

    if(CheckIntersect(animal, mushroom, 5))

    {

        //假如碰撞的位置属于蘑菇的左下位置

        if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.25))

        {

            horizontalSpeed = -speed;//反弹

        }

        //假如碰撞的位置属于蘑菇的左上位置

        else if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.5))

        {

            //反弹速度减半

            horizontalSpeed = -speed/2;

        }

        //假如碰撞的位置属于蘑菇的右上位置

        else if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.75))

        {

            horizontalSpeed = speed/2;

        }

        else

        {

            horizontalSpeed = speed;

        }

        verticalSpeed = -speed;//改变垂直速度。也即动物向上移动



    }

}

三、在游戏循环GameLoop()尾部中加入
JavaScript Code复制内容到剪贴板

//游戏功能循环

   function GameLoop()

   {

       //清除屏幕

       ctx.clearRect(0, 0, screenWidth, screenHeight);

       ctx.save();

       //绘制背景

       ctx.drawImage(backgroundForestImg, 0, 0);

       //绘制蘑菇

       ctx.drawImage(mushroom.image, mushroom.x, mushroom.y);

    //绘制熊

    //改变移动动物X和Y位置

    animal.x += horizontalSpeed;

    animal.y += verticalSpeed;

    //改变翻滚角度

    animal.angle += bearAngle;

    //以当前熊的中心位置为基准

        ctx.translate(animal.x + (animal.image.width/2), animal.y + (animal.image.height/2));

    //根据当前熊的角度轮换

    ctx.rotate(animal.angle * Math.PI/180);

    //描绘熊

    ctx.drawImage(animal.image, - (animal.image.width/2), - (animal.image.height/2));

       ctx.restore();

    //检测是否碰到边界

    HasAnimalHitEdge();

    //检测熊碰撞蘑菇

    HasAnimalHitMushroom();

       }

到此第五回的完整代码如下：

折叠展开XML/HTML Code复制内容到剪贴板

<!DOCTYPE>

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<title>蘑菇动起来-html5中文网</title>



<script type="text/javascript" src="./js/jquery-1.4.2.js"></script>

<script type="text/javascript" >

    //全局变量

    var backgroundForestImg = new Image();//森林背景图

    var mushroomImg = new Image();//蘑菇

    var bearEyesClosedImg = new Image();//闭着眼睛的熊熊

    var ctx;//2d画布

    var screenWidth;//画布宽度

    var screenHeight;//画布高度

    var speed = 2;//不变常量,从新开始的速度

    var horizontalSpeed = speed;//水平速度,随着熊的碰撞会发生改变

    var verticalSpeed = -speed; //垂直速度,开始肯定是要向上飘，所以要负数，随着熊的碰撞会发生改变

    var bearAngle = 2;//熊旋转的速度

    //公用定义一个游戏物体戏对象

    function GameObject()

    {

        this.x = 0;

        this.y = 0;

        this.image = null;

    }



    //定义蘑菇Mushroom 继承游戏对象GameObject

    function Mushroom() {};

    Mushroom.prototype = new GameObject();//游戏对象GameObject

    //蘑菇实例

    var mushroom = new Mushroom();        //循环描绘物体



    //定义动物熊 Animal 继承游戏对象GameObject

    function Animal() {};

    Animal.prototype = new GameObject();//游戏对象GameObject

    Animal.prototype.angle = 0;//动物的角度，目前中（即作为动物它在屏幕上旋转退回）

    //定义熊实例

    var animal = new Animal();

    //游戏功能循环

    function GameLoop()

    {

        //清除屏幕

        ctx.clearRect(0, 0, screenWidth, screenHeight);

        ctx.save();

        //绘制背景

        ctx.drawImage(backgroundForestImg, 0, 0);

        //绘制蘑菇

        ctx.drawImage(mushroom.image, mushroom.x, mushroom.y);

        //绘制熊

        //改变移动动物X和Y位置

        animal.x += horizontalSpeed;

        animal.y += verticalSpeed;

        //改变翻滚角度

        animal.angle += bearAngle;

        //以当前熊的中心位置为基准

        ctx.translate(animal.x + (animal.image.width/2), animal.y + (animal.image.height/2));

        //根据当前熊的角度轮换

        ctx.rotate(animal.angle * Math.PI/180);

        //描绘熊

        ctx.drawImage(animal.image, - (animal.image.width/2), - (animal.image.height/2));

        ctx.restore();

        //检测是否碰到边界

        HasAnimalHitEdge();

        //检测熊碰撞蘑菇

        HasAnimalHitMushroom();

        }

    //加载图片

    function LoadImages()

    {

        mushroomImg.src = "images/mushroom.png";//蘑菇

        backgroundForestImg.src = "images/forest1.jpg";//森林背景图

        bearEyesClosedImg.src = "images/bear_eyesclosed.png";//闭着眼睛的



        mushroom.image = mushroomImg;

        animal.image = bearEyesClosedImg;

    }

    //熊碰撞边界

    function HasAnimalHitEdge()

    {

        //熊碰到右边边界

        if(animal.x>screenWidth - animal.image.width)

        {

            if(horizontalSpeed > 0)//假如向右移动

                horizontalSpeed =-horizontalSpeed;//改变水平速度方向

        }

        //熊碰到左边边界

        if(animal.x<-10)

        {

            if(horizontalSpeed < 0)//假如向左移动

                horizontalSpeed = -horizontalSpeed;//改变水平速度方向

        }

        //熊碰到下面边界

        if(animal.y>screenHeight - animal.image.height)

        {

            //2秒钟后从新开始

            setTimeout(function(){

                horizontalSpeed = speed;

                verticalSpeed = -speed;

                animal.x = parseInt(screenWidth/2);

                animal.y = parseInt(screenHeight/2);

                gameLoop();

            }, 2000);

        }

        //熊碰到上边边界

        if(animal.y<0)

        {

            verticalSpeed = -verticalSpeed;

        }

    }

    //事件处理

    function AddEventHandlers()

    {

        //鼠标移动则蘑菇跟着移动

        $("#container").mousemove(function(e){

            mushroom.x = e.pageX - (mushroom.image.width/2);

        });



    }

    //方法用途：检测2个物体是否碰撞

    //参数object1：物体1

    //参数object1：物体2

    //参数overlap：可重叠的区域值

    //返回布尔值：碰撞返回true，不碰撞返回false

    function CheckIntersect(object1, object2, overlap)

    {

        //    x-轴                      x-轴

        //  A1------>B1 C1              A2------>B2 C2

        //  +--------+   ^              +--------+   ^

        //  | object1|   | y-轴         | object2|   | y-轴

        //  |        |   |              |        |   |

        //  +--------+  D1              +--------+  D2

        //  看图可知两物体各4个点的位置

        A1 = object1.x + overlap;

        B1 = object1.x + object1.image.width - overlap;

        C1 = object1.y + overlap;

        D1 = object1.y + object1.image.height - overlap;



        A2 = object2.x + overlap;

        B2 = object2.x + object2.image.width - overlap;

        C2 = object2.y + overlap;

        D2 = object2.y + object2.image.width - overlap;



        //假如他们在x-轴重叠

        if(A1 > A2 && A1 < B2

           || B1 > A2 && B1 < B2)

        {

            //判断y-轴重叠

            if(C1 > C2 && C1 < D1

           || D1 > C2 && D1 < D2)

            {

                //碰撞

                return true;

            }

        }

        return false;

    }

    //动物碰撞蘑菇

    function HasAnimalHitMushroom()

    {

        //假如碰撞

        if(CheckIntersect(animal, mushroom, 5))

        {

            //假如碰撞的位置属于蘑菇的左下位置

            if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.25))

            {

                horizontalSpeed = -speed;//反弹

            }

            //假如碰撞的位置属于蘑菇的左上位置

            else if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.5))

            {

                //反弹速度减半

                horizontalSpeed = -speed/2;

            }

            //假如碰撞的位置属于蘑菇的右上位置

            else if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.75))

            {

                horizontalSpeed = speed/2;

            }

            else

            {

                horizontalSpeed = speed;

            }

            verticalSpeed = -speed;//改变垂直速度。也即动物向上移动



        }

    }

    //初始化

    $(window).ready(function(){

        AddEventHandlers();//添加事件

        LoadImages();

        ctx = document.getElementById('canvas').getContext('2d'); //获取2d画布

        screenWidth = parseInt($("#canvas").attr("width")); //画布宽度

        screenHeight = parseInt($("#canvas").attr("height"));

        //初始化蘑菇

        mushroom.x = parseInt(screenWidth/2);// 蘑菇X坐标

        mushroom.y = screenHeight - 40;//蘑菇Y坐标

        //初始化熊

        animal.x = parseInt(screenWidth/2);

        animal.y = parseInt(screenHeight/2);

        setInterval(GameLoop, 10);

    });





</script>

</head>



<body>

    <div id="container" style="border:1px solid; cursor:none; width:480px; height:320px;">

        <canvas id="canvas" width="480" height="320" >

        浏览器不支持html5,<a target="_blank" href="http://www.html5china.com/help/browser.html">请下载</a>支持html5的浏览器来观看

        </canvas>

    </div>

       </body>

</html>

第五回就讲到这了，第六回讲描绘http://bbs.html5china.com/read.php?tid=2

希望大家在其他地方引用的时候，注明引用来自html5中文网

--作者：深邃老马

-----------------逆水行舟，不进则退

一步一步学做游戏 第五回：熊碰撞蘑菇处理

一步一步学做游戏第五回：熊碰撞蘑菇处理