WebGL Man

index.html

<canvas id="canvas"></canvas>

<script src="http://webgl2fundamentals.org/webgl/resources/twgl-full.min.js"></script>
<script src="http://webgl2fundamentals.org/webgl/resources/webgl-lessons-helper.js"></script>
<script src="http://webgl2fundamentals.org/webgl/resources/3d-math.js"></script>
<script src="http://webgl2fundamentals.org/webgl/resources/flattened-primitives.js"></script>

script.js

"use strict";

var vs = `#version 300 es

in vec4 a_position;
in vec4 a_color;

uniform mat4 u_matrix;

out vec4 v_color;

void main() {
  // Multiply the position by the matrix.
  gl_Position = u_matrix * a_position;

  // Pass the color to the fragment shader.
  v_color = a_color;
}
`;

var fs = `#version 300 es
precision mediump float;

// Passed in from the vertex shader.
in vec4 v_color;

uniform vec4 u_colorMult;
uniform vec4 u_colorOffset;

out vec4 outColor;

void main() {
   outColor = v_color * u_colorMult + u_colorOffset;
}
`;

var TRS = function() {
  this.translation = [0, 0, 0];
  this.rotation = [0, 0, 0];
  this.scale = [1, 1, 1];
};

TRS.prototype.getMatrix = function(dst) {
  dst = dst || new Float32Array(16);
  var t = this.translation;
  var r = this.rotation;
  var s = this.scale;

  // compute a matrix from translation, rotation, and scale
  m4.translation(t[0], t[1], t[2], dst);
  m4.xRotate(dst, r[0], dst);
  m4.yRotate(dst, r[1], dst);
  m4.zRotate(dst, r[2], dst);
  m4.scale(dst, s[0], s[1], s[2], dst);
  return dst;
};

var Node = function(source) {
  this.children = [];
  this.localMatrix = m4.identity();
  this.worldMatrix = m4.identity();
  this.source = source;
};

Node.prototype.setParent = function(parent) {
  // remove us from our parent
  if (this.parent) {
    var ndx = this.parent.children.indexOf(this);
    if (ndx >= 0) {
      this.parent.children.splice(ndx, 1);
    }
  }

  // Add us to our new parent
  if (parent) {
    parent.children.push(this);
  }
  this.parent = parent;
};

Node.prototype.updateWorldMatrix = function(matrix) {

  var source = this.source;
  if (source) {
    source.getMatrix(this.localMatrix);
  }

  if (matrix) {
    // a matrix was passed in so do the math
    m4.multiply(matrix, this.localMatrix, this.worldMatrix);
  } else {
    // no matrix was passed in so just copy.
    m4.copy(this.localMatrix, this.worldMatrix);
  }

  // now process all the children
  var worldMatrix = this.worldMatrix;
  this.children.forEach(function(child) {
    child.updateWorldMatrix(worldMatrix);
  });
};



function main() {
  // Get A WebGL context
  /** @type {HTMLCanvasElement} */
  var canvas = document.getElementById("canvas");
  var gl = canvas.getContext("webgl2");
  if (!gl) {
    return;
  }

  // Tell the twgl to match position with a_position, n
  // normal with a_normal etc..
  twgl.setAttributePrefix("a_");

  var cubeBufferInfo = flattenedPrimitives.createCubeBufferInfo(gl, 1);

  // setup GLSL program
  var programInfo = twgl.createProgramInfo(gl, [vs, fs]);

  var cubeVAO = twgl.createVAOFromBufferInfo(gl, programInfo, cubeBufferInfo);

  function degToRad(d) {
    return d * Math.PI / 180;
  }

  var fieldOfViewRadians = degToRad(60);

  var objectsToDraw = [];
  var objects = [];
  var nodeInfosByName = {};

  // Let's make all the nodes
  var blockGuyNodeDescriptions =
    {
      name: "point between feet",
      draw: false,
      children: [
        {
           name: "waist",
           translation: [0, 3, 0],
           children: [
             {
               name: "torso",
               translation: [0, 2, 0],
               children: [
                 {
                   name: "neck",
                   translation: [0, 1, 0],
                   children: [
                     {
                       name: "head",
                       translation: [0, 1, 0],
                     },
                   ],
                 },
                 {
                   name: "left-arm",
                   translation: [-1, 0, 0],
                   children: [
                     {
                       name: "left-forearm",
                       translation: [-1, 0, 0],
                       children: [
                         {
                           name: "left-hand",
                           translation: [-1, 0, 0],
                         },
                       ],
                     },
                   ],
                 },
                 {
                   name: "right-arm",
                   translation: [1, 0, 0],
                   children: [
                     {
                       name: "right-forearm",
                       translation: [1, 0, 0],
                       children: [
                         {
                           name: "right-hand",
                           translation: [1, 0, 0],
                         },
                       ],
                     },
                   ],
                 },
               ],
             },
             {
               name: "left-leg",
               translation: [-1, -1, 0],
               children: [
                 {
                   name: "left-calf",
                   translation: [0, -1, 0],
                   children: [
                     {
                       name: "left-foot",
                       translation: [0, -1, 0],
                     },
                   ],
                 },
               ],
             },
             {
               name: "right-leg",
               translation: [1, -1, 0],
               children: [
                 {
                   name: "right-calf",
                   translation: [0, -1, 0],
                   children: [
                     {
                       name: "right-foot",
                       translation: [0, -1, 0],
                     },
                   ],
                 },
               ],
             },
           ],
        },
      ],
    };

  function makeNode(nodeDescription) {
    var trs  = new TRS();
    var node = new Node(trs);
    nodeInfosByName[nodeDescription.name] = {
      trs: trs,
      node: node,
    };
    trs.translation = nodeDescription.translation || trs.translation;
    if (nodeDescription.draw !== false) {
      node.drawInfo = {
        uniforms: {
          u_colorOffset: [0, 0, 0.6, 0],
          u_colorMult: [0.6, 0.1, 0.1, 1],
        },
        programInfo: programInfo,
        bufferInfo: cubeBufferInfo,
        vertexArray: cubeVAO,
      };
      objectsToDraw.push(node.drawInfo);
      objects.push(node);
    }
    makeNodes(nodeDescription.children).forEach(function(child) {
      child.setParent(node);
    });
    return node;
  }

  function makeNodes(nodeDescriptions) {
    return nodeDescriptions ? nodeDescriptions.map(makeNode) : [];
  }

  var scene = makeNode(blockGuyNodeDescriptions);

  requestAnimationFrame(drawScene);

  // Draw the scene.
  function drawScene(time) {
    time *= 0.001;

    twgl.resizeCanvasToDisplaySize(gl.canvas);

    // Tell WebGL how to convert from clip space to pixels
    gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);

    gl.enable(gl.CULL_FACE);
    gl.enable(gl.DEPTH_TEST);

    // Compute the projection matrix
    var aspect = gl.canvas.clientWidth / gl.canvas.clientHeight;
    var projectionMatrix =
        m4.perspective(fieldOfViewRadians, aspect, 1, 200);

    // Compute the camera's matrix using look at.
    var cameraPosition = [4, 3.5, 10];
    var target = [0, 3.5, 0];
    var up = [0, 1, 0];
    var cameraMatrix = m4.lookAt(cameraPosition, target, up);

    // Make a view matrix from the camera matrix.
    var viewMatrix = m4.inverse(cameraMatrix);

    var viewProjectionMatrix = m4.multiply(projectionMatrix, viewMatrix);

    var adjust;
    var speed = 3;
    var c = time * speed;
    adjust = Math.abs(Math.sin(c));
    nodeInfosByName["point between feet"].trs.translation[1] = adjust;
    adjust = Math.sin(c);
    nodeInfosByName["left-leg" ].trs.rotation[0] =  adjust;
    nodeInfosByName["right-leg"].trs.rotation[0] = -adjust;
    adjust = Math.sin(c + 0.1) * 0.4;
    nodeInfosByName["left-calf" ].trs.rotation[0] = -adjust;
    nodeInfosByName["right-calf"].trs.rotation[0] =  adjust;
    adjust = Math.sin(c + 0.1) * 0.4;
    nodeInfosByName["left-foot" ].trs.rotation[0] = -adjust;
    nodeInfosByName["right-foot"].trs.rotation[0] =  adjust;

    adjust = Math.sin(c) * 0.4;
    nodeInfosByName["left-arm" ].trs.rotation[2] =  adjust;
    nodeInfosByName["right-arm"].trs.rotation[2] =  adjust;
    adjust = Math.sin(c + 0.1) * 0.4;
    nodeInfosByName["left-forearm" ].trs.rotation[2] =  adjust;
    nodeInfosByName["right-forearm"].trs.rotation[2] =  adjust;
    adjust = Math.sin(c - 0.1) * 0.4;
    nodeInfosByName["left-hand" ].trs.rotation[2] =  adjust;
    nodeInfosByName["right-hand"].trs.rotation[2] =  adjust;

    adjust = Math.sin(c) * 0.4;
    nodeInfosByName["waist"].trs.rotation[1] =  adjust;
    adjust = Math.sin(c) * 0.4;
    nodeInfosByName["torso"].trs.rotation[1] =  adjust;
    adjust = Math.sin(c + 0.25) * 0.4;
    nodeInfosByName["neck"].trs.rotation[1] =  adjust;
    adjust = Math.sin(c + 0.5) * 0.4;
    nodeInfosByName["head"].trs.rotation[1] =  adjust;
    adjust = Math.cos(c * 2) * 0.4;
    nodeInfosByName["head"].trs.rotation[0] =  adjust;

    // Update all world matrices in the scene graph
    scene.updateWorldMatrix();

    // Compute all the matrices for rendering
    objects.forEach(function(object) {
        object.drawInfo.uniforms.u_matrix = m4.multiply(viewProjectionMatrix, object.worldMatrix);
    });

    // ------ Draw the objects --------

    twgl.drawObjectList(gl, objectsToDraw);

    requestAnimationFrame(drawScene);
  }
}

main();

style.css

html {
  box-sizing: border-box;
}
*, *:before, *:after {
  box-sizing: inherit;
}

body {
  background-color: #aaa;
  font-family: Sans-Serif;
}

canvas {
  background-color: #fff;
  border: 1px solid black;
  /* NOTE: This size is changed if in iframe - see below '.iframe canvas' */
  width: 400px;
  height: 300px;
  display: block;
}

#uiContainer {
  position: absolute;
  top: 10px;
  right: 10px;
  z-index: 3;
  font-family: monospace;

  text-shadow:
   -1px -1px 0 #FFF,
    1px -1px 0 #FFF,
    -1px 1px 0 #FFF,
     1px 1px 0 #FFF;
}
#ui {
  opacity: 0.8;
}

.gman-slider-label {
  font-size: small;
  min-width: 10em;
  text-align: right;
}
.gman-slider-value {
  float: right;
  font-size: small;
  order: 1;
  min-width: 3em;
}

.gman-slider-upper {
  height: 1.5em;
}
.gman-slider-outer {
  float:right;
  display: flex;
  align-items: center;
  height: 1.7em;
}
.gman-slider-slider {
  opacity: 0.5;
  font-size: large;
  min-width: 120px;
  margin-left: .3em;
  margin-right: .3em;
}

/* styles to apply if in an iframe */

html.iframe {
    height: 100vh;
}
body.iframe {
  width: 100vw;
  height: 100vh;
  margin: 0;
  overflow: hidden;
}

.iframe>.description {
  display: none;
}
.iframe .divcavnas {
  width: 100vw;
  height: 100vh;
}
.iframe canvas {
  width: 100vw;
  height: 100vh;
  border: none;
}

.iframe>#example {
  width: 100%;
  height: 100%;
}
#ui #rotation>canvas {
  background-color: rgba(255, 255, 255, 0.6);
}
#ui {
    width: 200px;
}

.console {
    font-family: monospace;
    max-height: 50%;
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    overflow: auto;
    background: #DDD;
}
.console>div {
    white-space: pre-wrap;
    border-top: 1px solid black;
    padding-left: 0.2em;
    padding-right: 0.2em;
}
.console>.error {
    background: red;
    color: white;
}

.contextlost {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100vw;
    height: 100vh;
    position: absolute;
    left: 0;
    top: 0;
    background-color: rgba(0, 0, 0, 0.8);
    color: white;
    z-index: 10000;
}
.contextlost>div {
    padding: 1em;
    border-radius: 0.5em;
    background: red;
    color: white;
}

@media (max-width: 390px) {
  pre {
    font-size: xx-small !important;
    max-width: 300px !important;
  }
}

webgl-man.markdown

WebGL Man

A Pen by Saran Ahluwalia on CodePen.

License.