highd.js

var VSHADER_SOURCE =
  'attribute vec4 a_Position;\n\
  attribute vec4 a_Color;\n\
  varying vec4 v_Color;\n\
  void main() {\n\
    gl_Position = a_Position;\n\
    gl_PointSize = 6.0;\n\
    v_Color = a_Color;\n\
  }\n';

// Fragment shader program
var FSHADER_SOURCE =
  'precision mediump float;\n\
  varying vec4 v_Color;\n\
  void main() {\n\
    gl_FragColor = v_Color;\n\
  }\n';



function main() {
  // Retrieve <canvas> element
  var canvas = document.getElementById('webgl');
  canvas.width = window.innerHeight - 100;
  canvas.height = window.innerHeight - 100;

  // Get the rendering context for WebGL
  var gl = getWebGLContext(canvas);

  // Initialize shaders
  if (!initShaders(gl, VSHADER_SOURCE, FSHADER_SOURCE)) {
    console.log('Failed to intialize shaders.');
    return;
  }

  var n = initVertexBuffers(gl);

  // Clear the canvas
  gl.clearColor(1, 1, 1, 1);
  gl.clear(gl.COLOR_BUFFER_BIT);

  gl.drawArrays(gl.TRIANGLES, 0, n);
  //   }
}





function initVertexBuffers(gl) {
  // size of things
  var s = 0.2

  var cube = [[-1 * s, -1 * s, -1 * s], [-1 * s, -1 * s, s], [-1 * s, s, -1 * s], [-1 * s, s, s], [s, -1 * s, -1 * s], [s, -1 * s, s], [s, s, -1 * s], [s, s, s]];
  var cubeVerts = new Float32Array(48);
  for (var i = 0; i < 8; i++) {
    cubeVerts[6 * i] = cube[i][0];
    cubeVerts[6 * i + 1] = cube[i][1];
    cubeVerts[6 * i + 2] = cube[i][2];
    cubeVerts[6 * i + 3] = 0.5 // gray
    cubeVerts[6 * i + 4] = 0.5 // gray
    cubeVerts[6 * i + 5] = 0.5 // gray
  }

  // traingle
  var vertices = new Float32Array(
    [0, 0.5, 0.5, 0.5, 0.5,
      -0.5, -0.5, 0.5, 0.5, 0.5,
      0.5, -0.5, 0.5, 0.5, 0.5]); // triangle

  // number of vertices
  var n = 8;






  // Create a buffer object
  var vertexBuffer = gl.createBuffer();

  // Bind the buffer object to target
  gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer);
  // Write date into the buffer object
  gl.bufferData(gl.ARRAY_BUFFER, cubeVerts, gl.STATIC_DRAW);

  var FSIZE = vertices.BYTES_PER_ELEMENT;

  // does the position stuff with the buffer
  var a_Position = gl.getAttribLocation(gl.program, 'a_Position');
  gl.vertexAttribPointer(a_Position, 3, gl.FLOAT, false, FSIZE * 5, 0);
  gl.enableVertexAttribArray(a_Position);

  // IT IS SUPPOSED TO BE FSIZE * 6, BUT THIS LOOKS COOL TOO

  // does the colour stuff with the buffer
  var a_Color = gl.getAttribLocation(gl.program, 'a_Color');
  gl.vertexAttribPointer(a_Color, 3, gl.FLOAT, false, FSIZE * 5, FSIZE * 2);
  gl.enableVertexAttribArray(a_Color);  // Enable the assignment of the buffer object

  return n;
}