title: How to combine shader effects in threejs
body: <p>Coming from the Flash background, I'm used to creating a fragment shader in the following manner:</p>
  
  <pre><code>filters = [];
  
  filters.push(new BasicFilter(SomeTexture));
  filters.push(new NormalMapFilter(SomeOtherTexture));
  
  myShader = new Shader(filters);
  </code></pre>
  
  <p>As a result, I could combine a number of effects freely and easily without the need of writing a large separate shader each time.</p>
  
  <p>In case of threejs, I noticed that for complex visual effects, a single shader is written, like here: <a href="http://threejs.org/examples/#webgl_materials_bumpmap_skin" rel="noreferrer">http://threejs.org/examples/#webgl_materials_bumpmap_skin</a></p>
  
  <p>Is it possible to write e.g. a bump map shader and environment map shader separately and then combine them dynamically when needed? What would be the most proper way of doing this?</p>