canvas小遊戲程式碼例項

admin發表於2017-02-10
原文網址 : https://www.softwhy.com/article-697-1.html
Canvas遊戲
本章節分享一段程式碼例項，它實現利用canvas實現了一個小遊戲。

程式碼也是來源於網路，看起來比較長，感興趣的朋友可以自行分析借鑑。

程式碼如下:

[HTML] 純文字檢視 複製程式碼執行程式碼
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<meta name="author" content="http://www.softwhy.com/" />
<title>螞蟻部落</title>
<style>
 #canvas {
  display: block;
  margin: 20px auto;
}
</style>
<script>
window.onload = function () {
  var colors = ["#FFA54F", "#7CCD7C", "#836FFF"];
  var canvas = document.getElementById("canvas");
  var ctx = canvas.getContext("2d");
  ctx.drawCircle = function (x, y, value) {
    if (0 == value) return;
      var color = colors[value % 10 - 1];
      this.strokeStyle = color;
      this.fillStyle = color;
 
      this.beginPath();
      this.arc(x, y, 20, 2 * Math.PI, 0, false);
      this.closePath();
      this.stroke();
      if (value > 10) {
        this.fill();
      }
    }
 
    // 初始化圓
    var circles = [];
    for (var col = 0; col < 12; col++) {
      var arr = [];
      for (var row = 0; row < 12; row++) {
        var value = parseInt(Math.random() * colors.length) + 1;
        arr.push(value);
      }
      circles.push(arr);
    }
 
 
    var search_stack = [];
    var search_result = [];
    canvas.addEventListener("mousemove", function (event) {
      var col = parseInt((event.pageX - canvas.offsetLeft) / 40);
      var row = parseInt((event.pageY - canvas.offsetTop) / 40);
      if (0 == circles[col][row]) return;
 
      clean();
      search_stack.push({ row: row, col: col, value: circles[col][row] });
      search();
      recovery();
    }, false);
 
    // 清空，還原
    function clean() {
      if (search_result.length > 1) {
        search_result.forEach(function (item) {
          circles[item.col][item.row] -= 10;
        });
      }
 
      search_stack = [];
      search_result = [];
    }
 
    // 四鄰域遞迴搜尋
    function search() {
      if (search_stack.length == 0) return;
      var item = search_stack.pop();
      var value = item.value;
      var col = item.col;
      var row = item.row;
 
      circles[col][row] += 10;
      search_result.push({ row: row, col: col });
 
      // 上
      if (row > 0 && circles[col][row - 1] != 0 && circles[col][row - 1] < 10 && circles[col][row - 1] == value) {
        search_stack.push({ row: row - 1, col: col, value: circles[col][row - 1] });
      }
 
      // 下
      if (row < 11 && circles[col][row + 1] != 0 && circles[col][row + 1] < 10 && circles[col][row + 1] == value) {
        search_stack.push({ row: row + 1, col: col, value: circles[col][row + 1] });
      }
 
      // 左
      if (col > 0 && circles[col - 1][row] != 0 && circles[col - 1][row] < 10 && circles[col - 1][row] == value) {
        search_stack.push({ row: row, col: col - 1, value: circles[col - 1][row] });
      }
 
      // 右
      if (col < 11 && circles[col + 1][row] != 0 && circles[col + 1][row] < 10 && circles[col + 1][row] == value) {
        search_stack.push({ row: row, col: col + 1, value: circles[col + 1][row] });
      }
 
      search();
    }
 
    function recovery() {
      if (search_result.length == 1) {
        circles[search_result[0].col][search_result[0].row] -= 10;
      }
    }
 
    canvas.addEventListener("mousedown", function (event) {
      if (search_result.length < 2) return;
 
      // 等於0相當於刪除該元素
      for (var col = 0; col < 12; col++) {
        for (var row = 0; row < 12; row++) {
          if (circles[col][row] > 10) {
            circles[col][row] = 0;
          }
        }
      }
      search_result = [];
 
      // 下移
      for (var col = 0; col < 12; col++) {
        var temp_row = 11;
        for (var row = 11; row >= 0; row--) {
          if (circles[col][row] != 0) {
            circles[col][temp_row] = circles[col][row];
            temp_row--;
          }
        }
        for (var i = 0; i <= temp_row; i++) {
          circles[col]<i> = 0;
        }
      }
 
      // 左移
      for (var col = 0; col < 11; col++) {
        if (circles[col][11] == 0) {
          var target_col = col + 1;
          while (target_col < 11 && circles[target_col][11] == 0) target_col++;
          if (target_col > 11) break;
          for (var row = 0; row < 12; row++) {
            circles[col][row] = circles[target_col][row];
            circles[target_col][row] = 0;
          }
        }
      }
 
    }, false);
 
    setInterval(function () {
      ctx.clearRect(0, 0, 480, 480);
      for (var col = 0; col < 12; col++) {
        for (var row = 0; row < 12; row++) {
          ctx.drawCircle(20 + col * 40, 20 + row * 40, circles[col][row]);
        }
      }
    }, 33, false);
  }
</script>
</head>
<body>
<canvas id="canvas" width="480" height="480"></canvas>
</body>
</html>

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