在worker中使用offscreenCanvas

最新推荐文章于 2025-06-24 09:00:01 发布

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最新推荐文章于 2025-06-24 09:00:01 发布

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/wpw1215/p/9256054.html

本文介绍了一种利用HTML5的Canvas元素与WebGL技术进行离屏渲染的方法。通过将主屏幕Canvas转换为离屏Canvas，并传递给Web Worker进行独立渲染，实现了高效的图形处理。示例代码展示了如何设置HTML结构、JS交互逻辑以及WebGL渲染流程。

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HTML为

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>worker基本使用</title>
</head>
<body>
    <canvas id="myCanvas"></canvas>
    <button onclick="click()"></button>
</body>
<script>
  var offscreen = null;
  var worker = new Worker('offscreencanvas.js')
  function click () {
      if(offscreen == null){
          var htmlCanvas = document.getElementById('myCanvas')
          offscreen = htmlCanvas.ControlToOffscreen()
      }
      worker.postMessage({canvas:offscreen},[offscreen])
  }
</script>
</html>

Js代码为

var x = 50;
var y = 50;
var offCanvas = null;
onmessage = function(evt){
    if(offCanvas === null){
        offCanvas = evt.data.canvas
    } else{
        if(offCanvas == evt.data.canvas){
            console.log('offCanvas == evt.data.canvas')
        } else {
            console.log('offCanvas != evt.data.canvas')
        }
    }
    gl = offCanvas.getContext('webgl');
    gl.viewport(0, gl.drawingBufferWidth, gl.drawingBufferHeight);
    gl.enable(gl.SCLSSOR_TEST);
    gl.scissor(y, x, 60, 60);
    gl.clearColor(1.0, 0.0, 0.0, 1.0)//red
    gl.clear(gl.COLOR_BUFFER_BIT)
    gl.commit()
    x +=10
    y += 10
}