examples/vertex-array-objects.html

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    <title>twgl.js - vertex-array-objects</title>
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      canvas {
          display: block;
          width: 100vw;
          height: 100vh;
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      #b {
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  <body>
    <canvas id="c"></canvas>
    <div id="b"><a href="http://twgljs.org">twgl.js</a> - vertex-array-objects</div>
  </body>
  <script id="textured-vs" type="notjs">
uniform mat4 u_worldViewProjection;
uniform vec3 u_lightWorldPos;
uniform mat4 u_world;
uniform mat4 u_viewInverse;
uniform mat4 u_worldInverseTranspose;

attribute vec4 a_position;
attribute vec3 a_normal;
attribute vec2 a_texcoord;

varying vec4 v_position;
varying vec2 v_texCoord;
varying vec3 v_normal;
varying vec3 v_surfaceToLight;
varying vec3 v_surfaceToView;

void main() {
  v_texCoord = a_texcoord;
  v_position = (u_worldViewProjection * a_position);
  v_normal = (u_worldInverseTranspose * vec4(a_normal, 0)).xyz;
  v_surfaceToLight = u_lightWorldPos - (u_world * a_position).xyz;
  v_surfaceToView = (u_viewInverse[3] - (u_world * a_position)).xyz;
  gl_Position = v_position;
}
  </script>
  <script id="textured-fs" type="notjs">
precision mediump float;

varying vec4 v_position;
varying vec2 v_texCoord;
varying vec3 v_normal;
varying vec3 v_surfaceToLight;
varying vec3 v_surfaceToView;

uniform vec4 u_lightColor;
uniform vec4 u_diffuseMult;
uniform sampler2D u_diffuse;
uniform vec4 u_specular;
uniform float u_shininess;
uniform float u_specularFactor;

vec4 lit(float l ,float h, float m) {
  return vec4(1.0,
              abs(l),//max(l, 0.0),
              (l > 0.0) ? pow(max(0.0, h), m) : 0.0,
              1.0);
}

void main() {
  vec4 diffuseColor = texture2D(u_diffuse, v_texCoord) * u_diffuseMult;
  vec3 a_normal = normalize(v_normal);
  vec3 surfaceToLight = normalize(v_surfaceToLight);
  vec3 surfaceToView = normalize(v_surfaceToView);
  vec3 halfVector = normalize(surfaceToLight + surfaceToView);
  vec4 litR = lit(dot(a_normal, surfaceToLight),
                    dot(a_normal, halfVector), u_shininess);
  vec4 outColor = vec4((
  u_lightColor * (diffuseColor * litR.y +
                u_specular * litR.z * u_specularFactor)).rgb,
      diffuseColor.a);
  gl_FragColor = outColor;
}
  </script>
  <script id="ncolor-vs" type="notjs">
uniform mat4 u_worldViewProjection;
uniform vec3 u_lightWorldPos;
uniform mat4 u_world;
uniform mat4 u_viewInverse;
uniform mat4 u_worldInverseTranspose;

attribute vec4 a_position;
attribute vec3 a_normal;

varying vec4 v_position;
varying vec3 v_normal;
varying vec3 v_surfaceToLight;
varying vec3 v_surfaceToView;

void main() {
  v_position = (u_worldViewProjection * a_position);
  v_normal = (u_worldInverseTranspose * vec4(a_normal, 0)).xyz;
  v_surfaceToLight = u_lightWorldPos - (u_world * a_position).xyz;
  v_surfaceToView = (u_viewInverse[3] - (u_world * a_position)).xyz;
  gl_Position = v_position;
}
  </script>
  <script id="ncolor-fs" type="notjs">
precision mediump float;

varying vec4 v_position;
varying vec3 v_normal;
varying vec3 v_surfaceToLight;
varying vec3 v_surfaceToView;

uniform vec4 u_lightColor;
uniform vec4 u_diffuseMult;
uniform vec4 u_specular;
uniform float u_shininess;
uniform float u_specularFactor;

vec4 lit(float l ,float h, float m) {
  return vec4(1.0,
              abs(l),//max(l, 0.0),
              (l > 0.0) ? pow(max(0.0, h), m) : 0.0,
              1.0);
}

void main() {
  vec3 normal = normalize(v_normal);
  vec4 diffuseColor = vec4(normal * 0.5 + 0.5, 1);
  vec3 surfaceToLight = normalize(v_surfaceToLight);
  vec3 surfaceToView = normalize(v_surfaceToView);
  vec3 halfVector = normalize(surfaceToLight + surfaceToView);
  vec4 litR = lit(dot(normal, surfaceToLight),
                    dot(normal, halfVector), u_shininess);
  vec4 outColor = vec4((
  u_lightColor * (diffuseColor * litR.y +
                u_specular * litR.z * u_specularFactor)).rgb,
      diffuseColor.a);
  gl_FragColor = outColor;
}
  </script>
  <script src="../3rdparty/chroma.min.js"></script>
  <script type="module">
    import * as twgl from '../dist/6.x/twgl-full.module.js';
    twgl.setDefaults({attribPrefix: "a_"});
    const m4 = twgl.m4;
    const gl = document.getElementById("c").getContext('webgl2');
    if (!gl.createVertexArray) {
      alert("requires OES_vertex_array_object extension or WebGL 2");  // eslint-disable-line
    }

    // Passing in attribute names binds attribute location by index
    // In WebGL 2 we can also assign locations in GLSL (not sure which is better. This is global)
    //
    // We need to do this to make sure attirbute locations are consistent across
    // programs of else we'd need one vertex array object per program+bufferInfo combination
    const attributes = [
      "a_position",
      "a_normal",
      "a_texcoord",
    ];
    const texturedProgramInfo = twgl.createProgramInfo(gl, ["textured-vs", "textured-fs"], attributes);
    const vcolorProgramInfo = twgl.createProgramInfo(gl, ["ncolor-vs", "ncolor-fs"], attributes);

    const programInfos = [
      texturedProgramInfo,
      vcolorProgramInfo,
    ];

    const shapes = [
      twgl.createVertexArrayInfo(gl, programInfos, twgl.primitives.createCubeBufferInfo(gl, 2)),
      twgl.createVertexArrayInfo(gl, programInfos, twgl.primitives.createSphereBufferInfo(gl, 1, 24, 12)),
      twgl.createVertexArrayInfo(gl, programInfos, twgl.primitives.createPlaneBufferInfo(gl, 2, 2)),
      twgl.createVertexArrayInfo(gl, programInfos, twgl.primitives.createTruncatedConeBufferInfo(gl, 1, 0, 2, 24, 4)),
      twgl.createVertexArrayInfo(gl, programInfos, twgl.primitives.createCresentBufferInfo(gl, 1, 1, 0.5, 0.1, 24)),
      twgl.createVertexArrayInfo(gl, programInfos, twgl.primitives.createCylinderBufferInfo(gl, 1, 2, 24, 2)),
      twgl.createVertexArrayInfo(gl, programInfos, twgl.primitives.createDiscBufferInfo(gl, 1, 24, 4)),
      twgl.createVertexArrayInfo(gl, programInfos, twgl.primitives.createTorusBufferInfo(gl, 1, 0.4, 24, 12)),
    ];

    function rand(min, max) {
      if (max === undefined) {
        max = min;
        min = 0;
      }
      return min + Math.random() * (max - min);
    }

    // Shared values
    const lightWorldPosition = [1, 8, -10];
    const lightColor = [1, 1, 1, 1];
    const camera = m4.identity();
    const view = m4.identity();
    const viewProjection = m4.identity();

    const tex = twgl.createTexture(gl, {
      min: gl.NEAREST,
      mag: gl.NEAREST,
      src: [
        255, 255, 255, 255,
        192, 192, 192, 255,
        192, 192, 192, 255,
        255, 255, 255, 255,
      ],
    });

    const objects = [];
    const drawObjects = [];
    const numObjects = 100;
    const baseHue = rand(0, 360);
    for (let ii = 0; ii < numObjects; ++ii) {
      const uniforms = {
        u_lightWorldPos: lightWorldPosition,
        u_lightColor: lightColor,
        u_diffuseMult: chroma.hsv((baseHue + rand(0, 60)) % 360, 0.4, 0.8).gl(),
        u_specular: [1, 1, 1, 1],
        u_shininess: 50,
        u_specularFactor: 1,
        u_diffuse: tex,
        u_viewInverse: camera,
        u_world: m4.identity(),
        u_worldInverseTranspose: m4.identity(),
        u_worldViewProjection: m4.identity(),
      };
      drawObjects.push({
        programInfo: programInfos[rand(programInfos.length) | 0],
        vertexArrayInfo: shapes[ii % shapes.length],
        uniforms: uniforms,
      });
      objects.push({
        translation: [rand(-10, 10), rand(-10, 10), rand(-10, 10)],
        ySpeed: rand(-0.3, 0.3),
        zSpeed: rand(-0.3, 0.3),
        uniforms: uniforms,
      });
    }

    function render(time) {
      time *= 0.001;
      twgl.resizeCanvasToDisplaySize(gl.canvas);
      gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);

      gl.enable(gl.DEPTH_TEST);
      gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

      const projection = m4.perspective(30 * Math.PI / 180, gl.canvas.clientWidth / gl.canvas.clientHeight, 0.5, 100);
      const eye = [1, 4, -20];
      const target = [0, 0, 0];
      const up = [0, 1, 0];

      m4.lookAt(eye, target, up, camera);
      m4.inverse(camera, view);
      m4.multiply(projection, view, viewProjection);

      objects.forEach(function(obj) {
        const uni = obj.uniforms;
        const world = uni.u_world;
        m4.identity(world);
        m4.rotateY(world, time * obj.ySpeed, world);
        m4.rotateZ(world, time * obj.zSpeed, world);
        m4.translate(world, obj.translation, world);
        m4.rotateX(world, time, world);
        m4.transpose(m4.inverse(world, uni.u_worldInverseTranspose), uni.u_worldInverseTranspose);
        m4.multiply(viewProjection, uni.u_world, uni.u_worldViewProjection);
      });

      drawObjects.forEach(function(obj) {
        const programInfo = obj.programInfo;
        gl.useProgram(programInfo.program);
        twgl.setUniforms(programInfo, obj.uniforms);
        twgl.setBuffersAndAttributes(gl, programInfo, obj.vertexArrayInfo);
        twgl.drawBufferInfo(gl, obj.vertexArrayInfo);
      });

      requestAnimationFrame(render);
    }
    requestAnimationFrame(render);

  </script>
</html>