webglstuff.js

//From MDN Tutorial. No time to write my own.

function getShader(gl, id) {
  var shaderScript = document.getElementById(id);
  
  // Didn't find an element with the specified ID; abort.
  
  if (!shaderScript) {
    return null;
  }
  
  // Walk through the source element's children, building the
  // shader source string.
  
  var theSource = "";
  var currentChild = shaderScript.firstChild;
  
  while(currentChild) {
    if (currentChild.nodeType == 3) {
      theSource += currentChild.textContent;
    }
    
    currentChild = currentChild.nextSibling;
  }
  
  // Now figure out what type of shader script we have,
  // based on its MIME type.
  
  var shader;
  
  if (shaderScript.type == "x-shader/x-fragment") {
    shader = gl.createShader(gl.FRAGMENT_SHADER);
  } else if (shaderScript.type == "x-shader/x-vertex") {
    shader = gl.createShader(gl.VERTEX_SHADER);
  } else {
    return null;  // Unknown shader type
  }
  
  // Send the source to the shader object
  
  gl.shaderSource(shader, theSource);
  
  // Compile the shader program
  
  gl.compileShader(shader);
  
  // See if it compiled successfully
  
  if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
    alert("An error occurred compiling the shaders: " + gl.getShaderInfoLog(shader));
    return null;
  }
  
  return shader;
}