dom/canvas/test/webgl-conf/checkout/extra/program-test-1.html

   1 <!--
   2 Copyright (c) 2019 The Khronos Group Inc.
   3 Use of this source code is governed by an MIT-style license that can be
   4 found in the LICENSE.txt file.
   5 -->
   6 <!DOCTYPE html>
   7 <html>
   8 <head>
   9 <meta charset="utf-8">
  10 <!-- This is a visual test that programs must have both a vertex and
  11      fragment shader attached; the fixed function pipeline on the
  12      desktop must remain disabled. -->
  13 <script type="application/javascript">
  14 function log() {
  15   var s = "";
  16   for (var i = 0; i < arguments.length; ++i) {
  17     s += arguments[i] + " ";
  18   }
  19   document.getElementById("log").innerHTML += s + "<br>";
  20 }
  21
  22 function go() {
  23   var gl = document.getElementById("c").getContext("experimental-webgl");
  24
  25   gl.clearColor(0.0, 0.0, 0.0, 0.0);
  26   gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
  27
  28   var vs = gl.createShader(gl.VERTEX_SHADER);
  29   gl.shaderSource(vs, "attribute vec4 aVertex; attribute vec4 aColor; varying vec4 vColor; void main() { vColor = aColor; gl_Position = aVertex; }");
  30   gl.compileShader(vs);
  31
  32   var fs = gl.createShader(gl.FRAGMENT_SHADER);
  33   gl.shaderSource(fs, "precision mediump float; varying vec4 vColor; void main() { gl_FragColor = vColor; }");
  34   gl.compileShader(fs);
  35
  36   var prog = gl.createProgram();
  37   gl.attachShader(prog, vs);
  38   // don't attach a fragment shader -- may use fixed pipeline on desktop if the implementation doesn't check!
  39   //gl.attachShader(prog, fs);
  40
  41   gl.bindAttribLocation(prog, 0, "aVertex");
  42   gl.bindAttribLocation(prog, 1, "aColor");
  43
  44   gl.linkProgram(prog);
  45
  46   var vbuf = gl.createBuffer();
  47   gl.bindBuffer(gl.ARRAY_BUFFER, vbuf);
  48   gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
  49       -1.0, -1.0, 0.0, 1.0,
  50       -1.0, 1.0, 0.0, 1.0,
  51       1.0, -1.0, 0.0, 1.0,
  52       1.0, 1.0, 0.0, 1.0]), gl.STATIC_DRAW);
  53   gl.vertexAttribPointer(0, 4, gl.FLOAT, false, 0, 0);
  54
  55   var cbuf = gl.createBuffer();
  56   gl.bindBuffer(gl.ARRAY_BUFFER, cbuf);
  57   gl.bufferData(gl.ARRAY_BUFFER, new Uint8Array([255, 0, 0,
  58                                                  0, 255, 0,
  59                                                  0, 0, 255,
  60                                                  255, 255, 0]), gl.STATIC_DRAW);
  61   gl.vertexAttribPointer(1, 3, gl.UNSIGNED_BYTE, false, 0, 0);
  62
  63   gl.enableVertexAttribArray(0);
  64   gl.enableVertexAttribArray(1);
  65
  66   gl.useProgram(prog);
  67
  68   gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
  69
  70   log("glError", "0x" + gl.getError().toString(16));
  71 }
  72 </script>
  73 </head>
  74
  75 <body onload="go()">
  76 <p>Should be green in the rectangle below:</p>
  77 <canvas style="background: green;" id="c"></canvas>
  78 <div id="log"></div>
  79 </body>
  80 </html>