 nodes
  var sunNode = new Node();
  sunNode.localMatrix = m4.translation(0, 0, 0);  // sun a the center
  sunNode.drawInfo = {
    uniforms: {
      u_colorOffset: [0.6, 0.6, 0, 1], // yellow
      u_colorMult:   [0.4, 0.4, 0, 1],
    },
    programInfo: programInfo,
    bufferInfo: sphereBufferInfo,
    vertexArray: sphereVAO,
  };

  var earthNode = new Node();
  earthNode.localMatrix = m4.translation(100, 0, 0);  // earth 100 units from the sun
  earthNode.drawInfo = {
    uniforms: {
      u_colorOffse