案例查看地址：点击这里
<!doctype html> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> </head> <body οnlοad="main()"> <canvas id="canvas" height="400" width="400"> 你的浏览器不支持WebGL，请更换新的浏览器 </canvas> </body> <script src="lib/webgl-utils.js" ></script> <script src="lib/webgl-debug.js" ></script> <script src="lib/cuon-utils.js" ></script> <script> //顶点着色器程序 var VSHADER_SOURCE="" + "attribute vec4 a_Position;\n" + "void main(){\n" + " gl_Position = a_Position;\n" +//设置坐标 " gl_PointSize = 5.0;\n" +//设置尺寸 "}\n"; //片元着色器程序 var FSHADER_SOURCE = "" + "void main(){\n" + " gl_FragColor = vec4(1.0,0.0,0.0,1.0);\n" +//设置颜色 "}\n"; function main() { //首先获取到canvas的dom对象 var canvas = document.getElementById("canvas"); //获取到WebGL的上下文 var gl = getWebGLContext(canvas); //不支持WebGL的浏览器将打印一个错误，并结束代码运行 if (!gl) { console.log("浏览器不支持WebGL"); return; } //初始化着色器 if(!initShaders(gl,VSHADER_SOURCE,FSHADER_SOURCE)){ console.log("初始化着色器失败"); return; } //获取attribute变量的存储位置 var a_Position = gl.getAttribLocation(gl.program, "a_Position"); if(a_Position < 0){ console.log("无法获取变量的存储位置"); return; } //指定一个覆盖（清空）canvas的颜色 gl.clearColor(0.0, 0.0, 0.0, 1.0); //清除canvas gl.clear(gl.COLOR_BUFFER_BIT); //注册鼠标点击事件 canvas.onmousedown = function (event) { click(event,gl,canvas,a_Position); } var g_poiont = [];//声明一个可以存储点的信息的数组 function click(event,gl,canvas,a_Position) { var e = event || window.event; var x = e.clientX;//获取鼠标的点距离浏览器窗口最左边的距离 var y = e.clientY;//获取鼠标的点距离浏览器窗口最上面的距离 var rect = e.target.getBoundingClientRect();//组件封装方法，返回对象，里面含有点击的标签的距离浏览器左侧、上侧、右侧、下侧和自身的高宽 x = ((x-rect.left) - canvas.height/2)/(canvas.height/2);//计算出x轴WebGL的浮点数 y = (canvas.width/2 - (y - rect.top))/(canvas.width/2);//计算出y轴WebGL的浮点数 g_poiont.push({x:x,y:y});//将数据存入数组 //清除canvas gl.clear(gl.COLOR_BUFFER_BIT); var len = g_poiont.length; for(var i = 0; i<len; i++){//循环添加点 //将点的位置传递到变量中a_position gl.vertexAttrib3f(a_Position,g_poiont[i].x,g_poiont[i].y,0.0); //绘制点 gl.drawArrays(gl.POINTS,0,1); } } } </script> </html>组件库的下载 请看03 篇
