蘑菇與熊游戲開發(fā)第五回(熊碰撞蘑菇處理)
作者:admin
一、由于碰撞的地方比較多,所以定義一個(gè)通用的判斷2個(gè)物體是否碰撞的函數(shù)。二、熊碰撞蘑菇發(fā)生的事件以及處理。三、在游戲循環(huán)GameLoop()尾部中加入熊碰撞蘑菇函數(shù)。
第五回主要講熊碰到蘑菇之后向上反彈的效果
預(yù)期達(dá)到的效果:http://www.html5china.com/html5games/mogu/index4.html
一、由于碰撞的地方比較多,所以定義一個(gè)通用的判斷2個(gè)物體是否碰撞的函數(shù)
- //方法用途:檢測2個(gè)物體是否碰撞
- //參數(shù)object1:物體1
- //參數(shù)object1:物體2
- //參數(shù)overlap:可重疊的區(qū)域值
- //返回布爾值:碰撞返回true,不碰撞返回false
- function CheckIntersect(object1, object2, overlap)
- {
- // x-軸 x-軸
- // A1------>B1 C1 A2------>B2 C2
- // +--------+ ^ +--------+ ^
- // | object1| | y-軸 | object2| | y-軸
- // | | | | | |
- // +--------+ D1 +--------+ D2
- // 看圖可知兩物體各4個(gè)點(diǎn)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;
- //假如他們在x-軸重疊
- if(A1 > A2 && A1 < B2
- || B1 > A2 && B1 < B2)
- {
- //判斷y-軸重疊
- if(C1 > C2 && C1 < D1
- || D1 > C2 && D1 < D2)
- {
- //碰撞
- return true;
- }
- }
- return false;
- }
二、熊碰撞蘑菇發(fā)生的事件以及處理
- //動(dòng)物碰撞蘑菇
- function HasAnimalHitMushroom()
- {
- //假如碰撞
- if(CheckIntersect(animal, mushroom, 5))
- {
- //假如碰撞的位置屬于蘑菇的左下位置
- if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.25))
- {
- horizontalSpeed = -speed;//反彈
- }
- //假如碰撞的位置屬于蘑菇的左上位置
- else if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.5))
- {
- //反彈速度減半
- horizontalSpeed = -speed/2;
- }
- //假如碰撞的位置屬于蘑菇的右上位置
- else if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.75))
- {
- horizontalSpeed = speed/2;
- }
- else
- {
- horizontalSpeed = speed;
- }
- verticalSpeed = -speed;//改變垂直速度。也即動(dòng)物向上移動(dòng)
- }
- }
三、在游戲循環(huán)GameLoop()尾部中加入熊碰撞蘑菇函數(shù),如下
- //游戲功能循環(huán)
- function GameLoop()
- {
- //清除屏幕
- ctx.clearRect(0, 0, screenWidth, screenHeight);
- ctx.save();
- //繪制背景
- ctx.drawImage(backgroundForestImg, 0, 0);
- //繪制蘑菇
- ctx.drawImage(mushroom.image, mushroom.x, mushroom.y);
- //繪制熊
- //改變移動(dòng)動(dòng)物X和Y位置
- animal.x += horizontalSpeed;
- animal.y += verticalSpeed;
- //改變翻滾角度
- animal.angle += bearAngle;
- //以當(dāng)前熊的中心位置為基準(zhǔn)
- ctx.translate(animal.x + (animal.image.width/2), animal.y + (animal.image.height/2));
- //根據(jù)當(dāng)前熊的角度輪換
- ctx.rotate(animal.angle * Math.PI/180);
- //描繪熊
- ctx.drawImage(animal.image, - (animal.image.width/2), - (animal.image.height/2));
- ctx.restore();
- //檢測是否碰到邊界
- HasAnimalHitEdge();
- //檢測熊碰撞蘑菇
- HasAnimalHitMushroom();
- }
到此第五回的完整代碼如下:
- <!DOCTYPE>
- <html>
- <head>
- <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
- <title>蘑菇動(dòng)起來-html5中文網(wǎng)</title>
- <!-- 要記得引用jquery-1.4.2.js -->
- <script type="text/javascript" src="./js/jquery-1.4.2.js"></script>
- <script type="text/javascript" >
- //全局變量
- var backgroundForestImg = new Image();//森林背景圖
- var mushroomImg = new Image();//蘑菇
- var bearEyesClosedImg = new Image();//閉著眼睛的熊熊
- var ctx;//2d畫布
- var screenWidth;//畫布寬度
- var screenHeight;//畫布高度
- var speed = 2;//不變常量,從新開始的速度
- var horizontalSpeed = speed;//水平速度,隨著熊的碰撞會(huì)發(fā)生改變
- var verticalSpeed = -speed; //垂直速度,開始肯定是要向上飄,所以要負(fù)數(shù),隨著熊的碰撞會(huì)發(fā)生改變
- var bearAngle = 2;//熊旋轉(zhuǎn)的速度
- //公用 定義一個(gè)游戲物體戲?qū)ο?nbsp;
- function GameObject()
- {
- this.x = 0;
- this.y = 0;
- this.image = null;
- }
- //定義蘑菇Mushroom 繼承游戲?qū)ο驡ameObject
- function Mushroom() {};
- Mushroom.prototype = new GameObject();//游戲?qū)ο驡ameObject
- //蘑菇實(shí)例
- var mushroom = new Mushroom(); //循環(huán)描繪物體
- //定義動(dòng)物熊 Animal 繼承 游戲?qū)ο驡ameObject
- function Animal() {};
- Animal.prototype = new GameObject();//游戲?qū)ο驡ameObject
- Animal.prototype.angle = 0;//動(dòng)物的角度,目前中(即作為動(dòng)物它在屏幕上旋轉(zhuǎn)退回)
- //定義熊實(shí)例
- var animal = new Animal();
- //游戲功能循環(huán)
- function GameLoop()
- {
- //清除屏幕
- ctx.clearRect(0, 0, screenWidth, screenHeight);
- ctx.save();
- //繪制背景
- ctx.drawImage(backgroundForestImg, 0, 0);
- //繪制蘑菇
- ctx.drawImage(mushroom.image, mushroom.x, mushroom.y);
- //繪制熊
- //改變移動(dòng)動(dòng)物X和Y位置
- animal.x += horizontalSpeed;
- animal.y += verticalSpeed;
- //改變翻滾角度
- animal.angle += bearAngle;
- //以當(dāng)前熊的中心位置為基準(zhǔn)
- ctx.translate(animal.x + (animal.image.width/2), animal.y + (animal.image.height/2));
- //根據(jù)當(dāng)前熊的角度輪換
- ctx.rotate(animal.angle * Math.PI/180);
- //描繪熊
- ctx.drawImage(animal.image, - (animal.image.width/2), - (animal.image.height/2));
- ctx.restore();
- //檢測是否碰到邊界
- HasAnimalHitEdge();
- //檢測熊碰撞蘑菇
- HasAnimalHitMushroom();
- }
- //加載圖片
- function LoadImages()
- {
- mushroomImg.src = "images/mushroom.png";//蘑菇
- backgroundForestImg.src = "images/forest1.jpg";//森林背景圖
- bearEyesClosedImg.src = "images/bear_eyesclosed.png";//閉著眼睛的
- mushroom.image = mushroomImg;
- animal.image = bearEyesClosedImg;
- }
- //熊碰撞邊界
- function HasAnimalHitEdge()
- {
- //熊碰到右邊邊界
- if(animal.x>screenWidth - animal.image.width)
- {
- if(horizontalSpeed > 0)//假如向右移動(dòng)
- horizontalSpeed =-horizontalSpeed;//改變水平速度方向
- }
- //熊碰到左邊邊界
- if(animal.x<-10)
- {
- if(horizontalSpeed < 0)//假如向左移動(dòng)
- horizontalSpeed = -horizontalSpeed;//改變水平速度方向
- }
- //熊碰到下面邊界
- if(animal.y>screenHeight - animal.image.height)
- {
- //2秒鐘后從新開始
- setTimeout(function(){
- horizontalSpeed = speed;
- verticalSpeed = -speed;
- animal.x = parseInt(screenWidth/2);
- animal.y = parseInt(screenHeight/2);
- gameLoop();
- }, 2000);
- }
- //熊碰到上邊邊界
- if(animal.y<0)
- {
- verticalSpeed = -verticalSpeed;
- }
- }
- //事件處理
- function AddEventHandlers()
- {
- //鼠標(biāo)移動(dòng)則蘑菇跟著移動(dòng)
- $("#container").mousemove(function(e){
- mushroom.x = e.pageX - (mushroom.image.width/2);
- });
- }
- //方法用途:檢測2個(gè)物體是否碰撞
- //參數(shù)object1:物體1
- //參數(shù)object1:物體2
- //參數(shù)overlap:可重疊的區(qū)域值
- //返回布爾值:碰撞返回true,不碰撞返回false
- function CheckIntersect(object1, object2, overlap)
- {
- // x-軸 x-軸
- // A1------>B1 C1 A2------>B2 C2
- // +--------+ ^ +--------+ ^
- // | object1| | y-軸 | object2| | y-軸
- // | | | | | |
- // +--------+ D1 +--------+ D2
- // 看圖可知兩物體各4個(gè)點(diǎn)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;
- //假如他們在x-軸重疊
- if(A1 > A2 && A1 < B2
- || B1 > A2 && B1 < B2)
- {
- //判斷y-軸重疊
- if(C1 > C2 && C1 < D1
- || D1 > C2 && D1 < D2)
- {
- //碰撞
- return true;
- }
- }
- return false;
- }
- //動(dòng)物碰撞蘑菇
- function HasAnimalHitMushroom()
- {
- //假如碰撞
- if(CheckIntersect(animal, mushroom, 5))
- {
- //假如碰撞的位置屬于蘑菇的左下位置
- if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.25))
- {
- horizontalSpeed = -speed;//反彈
- }
- //假如碰撞的位置屬于蘑菇的左上位置
- else if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.5))
- {
- //反彈速度減半
- horizontalSpeed = -speed/2;
- }
- //假如碰撞的位置屬于蘑菇的右上位置
- else if((animal.x + animal.image.width/2) < (mushroom.x + mushroom.image.width*0.75))
- {
- horizontalSpeed = speed/2;
- }
- else
- {
- horizontalSpeed = speed;
- }
- verticalSpeed = -speed;//改變垂直速度。也即動(dòng)物向上移動(dòng)
- }
- }
- //初始化
- $(window).ready(function(){
- AddEventHandlers();//添加事件
- LoadImages();
- ctx = document.getElementById('canvas').getContext('2d'); //獲取2d畫布
- screenWidth = parseInt($("#canvas").attr("width")); //畫布寬度
- screenHeight = parseInt($("#canvas").attr("height"));
- //初始化蘑菇
- mushroom.x = parseInt(screenWidth/2);// 蘑菇X坐標(biāo)
- mushroom.y = screenHeight - 40;//蘑菇Y(jié)坐標(biāo)
- //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" >
- 瀏覽器不支持html5,<a target="_blank" href="http://www.html5china.com/help/browser.html">請下載</a>支持html5的瀏覽器來觀看
- </canvas>
- </div>
- </body>
- </html>
第五回就講到這了,第六回講描繪獎(jiǎng)品
【編輯推薦】
責(zé)任編輯:張偉
來源:
HTML5China