js canvas五子棋小游戏 js canvas实现五子棋小游戏

时间:2021-01-27 鱼-猫人气:0
效果
思路
canvans 绘制棋盘，绘制时候边缘预留棋子位置
监听点击事件绘制落子并记录到字典中
获胜判定，在四个方向上检测是否有足够数量的连贯棋子
代码
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>ym</title>
  <style>
    canvas {
      display: block;
      margin: 0 auto;
      border: 0
    }

    .result {
      text-align: center;
    }
    button{
      display: block;
      margin: 0 auto;
      padding: 4px 20px;
      border:0;
      color: #fff;
      outline: none;
      border-radius: 3px;
      background: #43a6ff
    }
    button:hover{
      font-weight: bold;
      cursor: pointer;
    }
  </style>
</head>
<body>
<canvas id="cv" width="200px" height="200px"></canvas>
<p class="result"></p>
<button onclick="loadPanel(400, 400,30,13)">刷新</button>
<script>

  loadPanel(400, 400,30,13);

  /**
   * 1) 点击落子并切换执子者
   * 2）以当前落子位置为基准，以‘米'字型判定，是否能构成五连及以上
   * @param w 棋盘宽度
   * @param h 棋盘高度
   * @param cs 格子尺寸
   * @param ps 棋子半径
   */
  function loadPanel(w, h, cs, ps) {
    let i, j, k;
    let chks = [[1, 0], [0, 1], [1, 1], [1, -1]];//水平，纵向，斜下，斜上 四个方向
    let successNum = 5;//赢棋标准
    let resultEl = document.querySelector('.result');

    //1)绘制棋盘,边缘应隔开棋子半径的距离
    cs = cs || 16;//默认格子宽高
    ps = ps || 4;//棋子半径
    h = h || w;//高度默认等于宽度

    let el = document.getElementById('cv');
    el.setAttribute('width', w + 'px');
    el.setAttribute('height', h + 'px');
    let context = el.getContext("2d");
    //计算棋盘分割，向下取整
    let splitX = ~~((w - 2 * ps) / cs), splitY = ~~((h - 2 * ps) / cs);

    //初始化落子位置使用字典存储，相较于数组简单且减少内存占用
    let pieces = {};
    //循环划线
    context.translate(ps, ps);
    context.beginPath();
    context.strokeStyle = '#000';
    //垂直线
    for (i = 0; i < splitX + 1; i++) {
      context.moveTo(cs * i, 0);
      context.lineTo(cs * i, splitY * cs);
      context.stroke();
    }
    //水平线
    for (j = 0; j < splitY + 1; j++) {
      context.moveTo(0, cs * j);
      context.lineTo(splitX * cs, cs * j);
      context.stroke();
    }
    context.closePath();

    let user = 0, colors = ['#000', '#fefefe'];
    el.addEventListener('click', function (e) {
      let x = e.offsetX,
        y = e.offsetY,
        //计算落子范围
        rx = ~~((x - ps) / cs) + (((x - ps) % cs <= cs / 2) ? 0 : 1),
        ry = ~~((y - ps) / cs) + (((y - ps) % cs <= cs / 2) ? 0 : 1);
      //绘制棋子
      context.beginPath();
      context.arc(cs * rx, cs * ry, ps, 2 * Math.PI, false);
      context.fillStyle = colors[user];
      context.strokeStyle = '#000';
      user ? user = 0 : user = 1;//切换执子者
      context.fill();
      context.stroke();
      context.closePath();

      //记录棋子位置
      let piece = pieces[rx + '-' + ry] = user;

      //米字型计算结果，以当前落子位置计算是否存在某个方向上具有连续的五个相同棋子
      for (j = 0; j < chks.length; j++) {
        let num = 1, chk = chks[j];
        for (i = 1; i <= 4; i++) {
          if (pieces[(rx + chk[0] * i) + '-' + (ry + chk[1] * i)] == piece) {
            num++
          } else {
            for (i = -1; i >= -4; i--) {
              if (pieces[(rx + chk[0] * i) + '-' + (ry + chk[1] * i)] == piece) {
                num++
              }
            }
            break
          }
        }
        if (num == successNum) {
          resultEl.innerHTML = ['白', '黑'][user] + '方赢';
          break;
        }
      }
    })
  }
</script>
</body>
</html>
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