title: WebGL: use both texture and color buffers
body: <p><a href="https://stackoverflow.com/questions/17313685/webgl-enablevertexattribarray-index-out-of-range">This question</a>, where the OP was reporting a warning being issued when executing instruction <code>gl.enableVertexAttribArray(shaderProgram.textureCoordAttribute);</code> got me thinking: what if I want to have a scene with two (let's assume: flat) shapes in it, one with a texture and one with a uniform color? In the fragment shader's <code>main</code>, if I uncomment the second instruction and comment out the first, like so:</p>
  
  <pre><code>void main(void) {
      //gl_FragColor = vColor;
      gl_FragColor = texture2D(uSampler, vec2(vTextureCoord.s, vTextureCoord.t));
  }
  </code></pre>
  
  <p>the warning is still being issued, but this time in regards to the instruction <code>gl.enableVertexAttribArray(shaderProgram.vertexColorAttribute);</code>.<br>
  If I leave both uncommented, it still complains about the vertexColorAttribute because clearly it's being overridden.<br>
  So how can I have both? Am I to use two different fragment shaders? If so, how can it be done?</p>