{"id":4477,"date":"2023-03-29T01:43:39","date_gmt":"2023-03-28T16:43:39","guid":{"rendered":"https:\/\/engineering.webstudio168.jp\/?p=4477"},"modified":"2023-03-30T15:22:59","modified_gmt":"2023-03-30T06:22:59","slug":"javascript-canvas-rainy","status":"publish","type":"post","link":"https:\/\/engineering.webstudio168.jp\/blog\/javascript-canvas-rainy\/","title":{"rendered":"JavaScript\u3067Canvas\u306b\u96e8\u3092\u964d\u3089\u305b\u308b\u30ae\u30df\u30c3\u30af\u30b5\u30f3\u30d7\u30eb\u3010jQuery\u7121\u3057\u3011"},"content":{"rendered":"\n<canvas id=\"myCanvas\"><\/canvas>\n<script>\n\/\/ Canvas\u306e\u8981\u7d20\u3092\u53d6\u5f97\u3059\u308b\nvar canvas = document.getElementById(\"myCanvas\");\n\n\/\/ Canvas\u306e\u63cf\u753b\u30b3\u30f3\u30c6\u30ad\u30b9\u30c8\u3092\u53d6\u5f97\u3059\u308b\nvar ctx = canvas.getContext(\"2d\");\n\n\/\/ \u96e8\u7c92\u306e\u6570\nvar drops = [];\n\n\/\/ \u96e8\u7c92\u306e\u8a2d\u5b9a\nfunction RainDrop() {\n  \/\/ \u96e8\u7c92\u306e\u521d\u671f\u4f4d\u7f6e\u3092\u30e9\u30f3\u30c0\u30e0\u306b\u8a2d\u5b9a\n  this.x = Math.random() * canvas.width;\n  this.y = Math.random() * -canvas.height;\n  \n  \/\/ \u96e8\u7c92\u306e\u843d\u4e0b\u30b9\u30d4\u30fc\u30c9\u3092\u30e9\u30f3\u30c0\u30e0\u306b\u8a2d\u5b9a\n  this.speed = Math.random() * 50 + 5;\n  \n  \/\/ \u96e8\u7c92\u306e\u534a\u5f84\u3092\u30e9\u30f3\u30c0\u30e0\u306b\u8a2d\u5b9a\n  this.radius = Math.random() * 0.2 + 1;\n  \n  \/\/ \u96e8\u7c92\u3092\u63cf\u753b\u3059\u308b\u95a2\u6570\n  this.draw = function() {\n    ctx.beginPath();\n    ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2);\n    ctx.fillStyle = \"#FFFFFF\";\n    ctx.fill();\n    ctx.closePath();\n  }\n}\n\n\/\/ \u96e8\u7c92\u3092\u8ffd\u52a0\u3059\u308b\u95a2\u6570\nfunction addRainDrop() {\n  drops.push(new RainDrop());\n}\n\n\/\/ \u96e8\u7c92\u3092\u66f4\u65b0\u3059\u308b\u95a2\u6570\nfunction updateRainDrops() {\n  for (var i = 0; i < drops.length; i++) {\n    \/\/ \u96e8\u7c92\u3092\u843d\u4e0b\u3055\u305b\u308b\n    drops[i].y += drops[i].speed;\n    \n    \/\/ \u96e8\u7c92\u304cCanvas\u306e\u4e0b\u7aef\u306b\u9054\u3057\u305f\u3089\u3001\u753b\u9762\u4e0a\u304b\u3089\u6d88\u3059\n    if (drops[i].y > canvas.height) {\n      drops.splice(i, 1);\n      i--;\n    }\n  }\n}\n\n\/\/ \u96e8\u7c92\u3092\u63cf\u753b\u3059\u308b\u95a2\u6570\nfunction drawRainDrops() {\n  for (var i = 0; i < drops.length; i++) {\n    drops[i].draw();\n  }\n}\n\n\/\/ \u30a2\u30cb\u30e1\u30fc\u30b7\u30e7\u30f3\u3092\u958b\u59cb\u3059\u308b\u95a2\u6570\nfunction startAnimation() {\n  setInterval(function() {\n    \/\/ Canvas\u3092\u30af\u30ea\u30a2\u3059\u308b\n    ctx.clearRect(0, 0, canvas.width, canvas.height);\n    \n    \/\/ \u96e8\u7c92\u3092\u8ffd\u52a0\u3059\u308b\n    addRainDrop();\n    \n    \/\/ \u96e8\u7c92\u3092\u66f4\u65b0\u3059\u308b\n    updateRainDrops();\n    \n    \/\/ \u96e8\u7c92\u3092\u63cf\u753b\u3059\u308b\n    drawRainDrops();\n  }, 1);\n}\n\n\/\/ \u30a2\u30cb\u30e1\u30fc\u30b7\u30e7\u30f3\u3092\u958b\u59cb\u3059\u308b\nstartAnimation();<\/script>\n<style>\ncanvas#myCanvas {\nbackground: #333;\nwidth: 100%;\nheight: 300px;\n}\n<\/style>\n\n\n\n<p class=\"wp-block-paragraph\">\u96e8\u3092\u964d\u3089\u305b\u3066\u307f\u307e\u3057\u305f\u3002\u3069\u3061\u3089\u304b\u3068\u3044\u3046\u3068\u96ea\u306e\u3088\u3046\u306b\u3082\u611f\u3058\u307e\u3059\u304c\u2026\u2026\u8272\u3005\u6570\u5024\u3092\u3044\u3058\u308c\u3070\u9060\u8fd1\u611f\u304c\u51fa\u305f\u308a\u3001\u7dda\u72b6\uff08\u96e8\u306e\u8d77\u52d5\uff09\u306b\u3057\u305f\u308a\u6c4e\u7528\u7684\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u3002\u4f7f\u3046\u6a5f\u4f1a\u304c\u3042\u308c\u3070\u662f\u975e\u53c2\u8003\u306b\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism undefined-numbers lang-html\" data-file=\"js-canvas-rain.html\" data-lang=\"HTML\"><code>&lt;canvas id=&quot;myCanvas&quot;&gt;&lt;\/canvas&gt;\n&lt;script&gt;\n  \/\/ Canvas\u306e\u8981\u7d20\u3092\u53d6\u5f97\u3059\u308b\n  var canvas = document.getElementById(&quot;myCanvas&quot;);\n\n  \/\/ Canvas\u306e\u63cf\u753b\u30b3\u30f3\u30c6\u30ad\u30b9\u30c8\u3092\u53d6\u5f97\u3059\u308b\n  var ctx = canvas.getContext(&quot;2d&quot;);\n\n  \/\/ \u96e8\u7c92\u306e\u6570\n  var drops = [];\n\n  \/\/ \u96e8\u7c92\u306e\u8a2d\u5b9a\n  function RainDrop() {\n    \/\/ \u96e8\u7c92\u306e\u521d\u671f\u4f4d\u7f6e\u3092\u30e9\u30f3\u30c0\u30e0\u306b\u8a2d\u5b9a\n    this.x = Math.random() * canvas.width;\n    this.y = Math.random() * -canvas.height;\n\n    \/\/ \u96e8\u7c92\u306e\u843d\u4e0b\u30b9\u30d4\u30fc\u30c9\u3092\u30e9\u30f3\u30c0\u30e0\u306b\u8a2d\u5b9a\n    this.speed = Math.random() * 50 + 5;\n\n    \/\/ \u96e8\u7c92\u306e\u534a\u5f84\u3092\u30e9\u30f3\u30c0\u30e0\u306b\u8a2d\u5b9a\n    this.radius = Math.random() * 0.2 + 1;\n\n    \/\/ \u96e8\u7c92\u3092\u63cf\u753b\u3059\u308b\u95a2\u6570\n    this.draw = function () {\n      ctx.beginPath();\n      ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2);\n      ctx.fillStyle = &quot;#FFFFFF&quot;;\n      ctx.fill();\n      ctx.closePath();\n    }\n  }\n\n  \/\/ \u96e8\u7c92\u3092\u8ffd\u52a0\u3059\u308b\u95a2\u6570\n  function addRainDrop() {\n    drops.push(new RainDrop());\n  }\n\n  \/\/ \u96e8\u7c92\u3092\u66f4\u65b0\u3059\u308b\u95a2\u6570\n  function updateRainDrops() {\n    for (var i = 0; i &lt; drops.length; i++) {\n      \/\/ \u96e8\u7c92\u3092\u843d\u4e0b\u3055\u305b\u308b\n      drops[i].y += drops[i].speed;\n\n      \/\/ \u96e8\u7c92\u304cCanvas\u306e\u4e0b\u7aef\u306b\u9054\u3057\u305f\u3089\u3001\u753b\u9762\u4e0a\u304b\u3089\u6d88\u3059\n      if (drops[i].y &gt; canvas.height) {\n        drops.splice(i, 1);\n        i--;\n      }\n    }\n  }\n\n  \/\/ \u96e8\u7c92\u3092\u63cf\u753b\u3059\u308b\u95a2\u6570\n  function drawRainDrops() {\n    for (var i = 0; i &lt; drops.length; i++) {\n      drops[i].draw();\n    }\n  }\n\n  \/\/ \u30a2\u30cb\u30e1\u30fc\u30b7\u30e7\u30f3\u3092\u958b\u59cb\u3059\u308b\u95a2\u6570\n  function startAnimation() {\n    setInterval(function () {\n      \/\/ Canvas\u3092\u30af\u30ea\u30a2\u3059\u308b\n      ctx.clearRect(0, 0, canvas.width, canvas.height);\n\n      \/\/ \u96e8\u7c92\u3092\u8ffd\u52a0\u3059\u308b\n      addRainDrop();\n\n      \/\/ \u96e8\u7c92\u3092\u66f4\u65b0\u3059\u308b\n      updateRainDrops();\n\n      \/\/ \u96e8\u7c92\u3092\u63cf\u753b\u3059\u308b\n      drawRainDrops();\n    }, 1);\n  }\n\n  \/\/ \u30a2\u30cb\u30e1\u30fc\u30b7\u30e7\u30f3\u3092\u958b\u59cb\u3059\u308b\n  startAnimation();\n&lt;\/script&gt;\n&lt;style&gt;\n  canvas#myCanvas {\n    background: #333;\n    width: 100%;\n    height: 300px;\n  }\n&lt;\/style&gt;<\/code><\/pre><\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u96e8\u3092\u964d\u3089\u305b\u3066\u307f\u307e\u3057\u305f\u3002\u3069\u3061\u3089\u304b\u3068\u3044\u3046\u3068\u96ea\u306e\u3088\u3046\u306b\u3082\u611f\u3058\u307e\u3059\u304c\u2026\u2026\u8272\u3005\u6570\u5024\u3092\u3044\u3058\u308c\u3070\u9060\u8fd1\u611f\u304c\u51fa\u305f\u308a\u3001\u7dda\u72b6\uff08\u96e8\u306e\u8d77\u52d5\uff09\u306b\u3057\u305f\u308a\u6c4e\u7528\u7684\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u3002\u4f7f\u3046\u6a5f\u4f1a\u304c\u3042\u308c\u3070\u662f\u975e\u53c2\u8003\u306b\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n","protected":false},"author":1,"featured_media":4493,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[55],"tags":[8,91],"class_list":["post-4477","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-javascript","tag-javascript","tag-91"],"_links":{"self":[{"href":"https:\/\/engineering.webstudio168.jp\/blog\/wp-json\/wp\/v2\/posts\/4477","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/engineering.webstudio168.jp\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/engineering.webstudio168.jp\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/engineering.webstudio168.jp\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/engineering.webstudio168.jp\/blog\/wp-json\/wp\/v2\/comments?post=4477"}],"version-history":[{"count":17,"href":"https:\/\/engineering.webstudio168.jp\/blog\/wp-json\/wp\/v2\/posts\/4477\/revisions"}],"predecessor-version":[{"id":4517,"href":"https:\/\/engineering.webstudio168.jp\/blog\/wp-json\/wp\/v2\/posts\/4477\/revisions\/4517"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/engineering.webstudio168.jp\/blog\/wp-json\/wp\/v2\/media\/4493"}],"wp:attachment":[{"href":"https:\/\/engineering.webstudio168.jp\/blog\/wp-json\/wp\/v2\/media?parent=4477"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/engineering.webstudio168.jp\/blog\/wp-json\/wp\/v2\/categories?post=4477"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/engineering.webstudio168.jp\/blog\/wp-json\/wp\/v2\/tags?post=4477"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}