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JS实现飞行的小鸟游戏-简易版

2022-03-20 09:32:29 作者：互联网
效果图：
实现代码：
<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>飞行游戏</title>
  <style>
    canvas {
      border:1px solid #d3d3d3;
      background-color: #f1f1f1;
    }
  </style>
  <script>
    (function() {
      const hm = document.createElement("script");
      hm.src = "//hm.baidu.com/hm.js?73c27e26f610eb3c9f3feb0c75b03925";
      const s = document.getElementsByTagName("script")[0];
      s.parentNode.insertBefore(hm, s);
    })();
  </script>
</head>
<body onl oad="startGame()">
<script>

  let myGamePiece;
  const myObstacles = [];
  let myScore;

  function startGame() {
    myGamePiece = new component(30, 30, "red", 10, 120);
    myGamePiece.gravity = 0.05;
    myScore = new component("30px", "Consolas", "black", 280, 40, "text");
    myGameArea.start();
  }

  const myGameArea = {
    canvas : document.createElement("canvas"),
    start : function() {
      this.canvas.width = 480;
      this.canvas.height = 270;
      this.context = this.canvas.getContext("2d");
      document.body.insertBefore(this.canvas, document.body.childNodes[0]);
      this.frameNo = 0;
      this.interval = setInterval(updateGameArea, 20);
    },
    clear : function() {
      this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
    }
  }

  function component(width, height, color, x, y, type) {
    this.type = type;
    this.score = 0;
    this.width = width;
    this.height = height;
    this.speedX = 0;
    this.speedY = 0;
    this.x = x;
    this.y = y;
    this.gravity = 0;
    this.gravitySpeed = 0;
    this.update = function() {
      ctx = myGameArea.context;
      if (this.type == "text") {
        ctx.font = this.width + " " + this.height;
        ctx.fillStyle = color;
        ctx.fillText(this.text, this.x, this.y);
      } else {
        ctx.fillStyle = color;
        ctx.fillRect(this.x, this.y, this.width, this.height);
      }
    }
    this.newPos = function() {
      this.gravitySpeed += this.gravity;
      this.x += this.speedX;
      this.y += this.speedY + this.gravitySpeed;
      this.hitBottom();
    }
    this.hitBottom = function() {
      var rockbottom = myGameArea.canvas.height - this.height;
      if (this.y > rockbottom) {
        this.y = rockbottom;
        this.gravitySpeed = 0;
      }
    }
    this.crashWith = function(otherobj) {
      const myleft = this.x;
      const myright = this.x + (this.width);
      const mytop = this.y;
      const mybottom = this.y + (this.height);
      const otherleft = otherobj.x;
      const otherright = otherobj.x + (otherobj.width);
      const othertop = otherobj.y;
      const otherbottom = otherobj.y + (otherobj.height);
      let crash = true;
      if ((mybottom < othertop) || (mytop > otherbottom) || (myright < otherleft) || (myleft > otherright)) {
        crash = false;
      }
      return crash;
    }
  }

  function updateGameArea() {
    var x, height, gap, minHeight, maxHeight, minGap, maxGap;
    for (i = 0; i < myObstacles.length; i += 1) {
      if (myGamePiece.crashWith(myObstacles[i])) {
        return;
      }
    }
    myGameArea.clear();
    myGameArea.frameNo += 1;
    if (myGameArea.frameNo == 1 || everyinterval(150)) {
      x = myGameArea.canvas.width;
      minHeight = 20;
      maxHeight = 200;
      height = Math.floor(Math.random()*(maxHeight-minHeight+1)+minHeight);
      minGap = 50;
      maxGap = 200;
      gap = Math.floor(Math.random()*(maxGap-minGap+1)+minGap);
      myObstacles.push(new component(10, height, "green", x, 0));
      myObstacles.push(new component(10, x - height - gap, "green", x, height + gap));
    }
    for (i = 0; i < myObstacles.length; i += 1) {
      myObstacles[i].x += -1;
      myObstacles[i].update();
    }
    myScore.text="SCORE: " + myGameArea.frameNo;
    myScore.update();
    myGamePiece.newPos();
    myGamePiece.update();
  }

  function everyinterval(n) {
    return (myGameArea.frameNo / n) % 1 == 0;

  }

  function accelerate(n) {
    myGamePiece.gravity = n;
  }
</script>
<br>
<button onm ousedown="accelerate(-0.2)" onm ouseup="accelerate(0.05)">ACCELERATE</button>
<p>Use the ACCELERATE button to stay in the air</p>
<p>How long can you stay alive?</p>
</body>
</html>
标签：function,myGameArea,canvas,const,height,小鸟,width,简易版,JS
来源： https://blog.csdn.net/weixin_40845165/article/details/123607701