一、代码综述
function gameStart() { let container = document.createElement('div'); container.className = 'container'; let character = document.createElement('div'); character.className = 'character'; let ground = document.createElement('div'); ground.className = 'ground'; container.appendChild(character); container.appendChild(ground); document.body.appendChild(container); let gravity = 0.2; let velocity = 0; let jumpStrength = -5; let keys = {}; document.addEventListener('keydown', function(event) { keys[event.keyCode] = true; }); document.addEventListener('keyup', function(event) { keys[event.keyCode] = false; }); function loop() { if (keys['32'] || keys['38']) { if (character.classList != 'character jump') { character.classList.add('jump'); velocity = jumpStrength; } } velocity += gravity; character.style.top = character.offsetTop + velocity + 'px'; if (character.offsetTop + character.offsetHeight > ground.offsetTop) { character.style.top = ground.offsetTop - character.offsetHeight + 'px'; velocity = 0; character.classList.remove('jump'); } window.requestAnimationFrame(loop); } loop(); } gameStart();小恐龙无敌代码是一段Javascript程序,它实现了一个简单的小恐龙跳跃游戏。代码包含一个名为gameStart()的函数,在页面加载时自动调用该函数创建游戏的主要元素。函数主体内部定义了一些变量和函数,以及通过addEventListener()函数来响应玩家的按键操作,实现小恐龙的跳跃。
二、小标题1 - 游戏元素
小恐龙无敌代码中主要涉及到三个游戏元素,分别是容器(container)、角色(character)和地面(ground)。
容器是一个
.container{ position:relative; width:100vw; height:100vh; overflow:hidden; background-color:#f7f7f7; } .character{ position:absolute; left:calc(50vw - 25px); bottom:0; width:50px; height:50px; background-color:#555; } .ground{ position:absolute; left:0; bottom:0; width:100%; height:10px; background-color:#333; }
三、小标题2 - 跳跃动作
小恐龙无敌代码中通过监听玩家的按键操作,响应空格键或者上箭头键来使小恐龙跳跃。跳跃动作的具体实现是通过character元素的CSS类名来控制的,如果没有跳跃动作,character元素的类名是'character',如果正在跳跃,character元素的类名则为'character jump'。
document.addEventListener('keydown', function(event) { keys[event.keyCode] = true; }); document.addEventListener('keyup', function(event) { keys[event.keyCode] = false; }); if (keys['32'] || keys['38']) { if (character.classList != 'character jump') { character.classList.add('jump'); velocity = jumpStrength; } } if (character.offsetTop + character.offsetHeight > ground.offsetTop) { character.style.top = ground.offsetTop - character.offsetHeight + 'px'; velocity = 0; character.classList.remove('jump'); }
四、小标题3 - 主循环
小恐龙无敌代码的主要逻辑是通过一个主循环来实现的。主循环使用了requestAnimationFrame()函数每帧更新小恐龙的位置,并且根据小恐龙当前位置和跳跃状态来计算velocity变量的值,以实现小恐龙的跳跃和落地动作。
let gravity = 0.2; let velocity = 0; let jumpStrength = -5; function loop() { if (keys['32'] || keys['38']) { if (character.classList != 'character jump') { character.classList.add('jump'); velocity = jumpStrength; } } velocity += gravity; character.style.top = character.offsetTop + velocity + 'px'; if (character.offsetTop + character.offsetHeight > ground.offsetTop) { character.style.top = ground.offsetTop - character.offsetHeight + 'px'; velocity = 0; character.classList.remove('jump'); } window.requestAnimationFrame(loop); } loop();