o3djs.shape.prepareShapes = function(pack) {
    var shapes = pack.getObjectsByClassName('o3d.Shape');
    for (var ss = 0; ss < shapes.length; ++ss) {
      var shape = shapes[ss];
      shape.createDrawElements(pack, null);
      var elements = shape.elements;
      for (var ee = 0; ee < elements.length; ++ee) {
        var element = elements[ee];
        var boundingBox = element.getBoundingBox(0);
        var minExtent = boundingBox.minExtent;
        var maxExtent = boundingBox.maxExtent;
        element.boundingBox = boundingBox;
        element.cull = true;
        element.zSortPoint = o3djs.math.div(
            o3djs.math.add(minExtent, maxExtent), 2);
  
        // This is very application specific but if it's a primitive
        // and if it uses a collada material the material builder
        // assumes 1 TEXCOORD stream per texture. In other words if you have
        // both a specular texture AND a diffuse texture the builder assumes
        // you have 2 TEXCOORD streams. This assumption is often false.
        //
        // To work around this we check how many streams the material
        // expects and if there are not enough UVs streams we duplicate the
        // last TEXCOORD stream until there are, making a BIG assumption that
        // that will work.
        //
        // The problem is maybe you have 4 textures and each of them share
        // texture coordinates. There is information in the collada file about
        // what stream to connect each texture to.
        //
        // TODO We should store that info. The conditioner should either
        // make streams that way or pass on the info so we can do it here.
        if (element.isAClassName('o3d.Primitive')) {
          var material = element.material;
          var streamBank = element.streamBank;
          var lightingType = o3djs.effect.getColladaLightingType(material);
          if (lightingType) {
            var numTexCoordStreamsNeeded =
                o3djs.effect.getNumTexCoordStreamsNeeded(material);
            // Count the number of TEXCOORD streams the streamBank has.
            var streams = streamBank.vertexStreams;
            var lastTexCoordStream = null;
            var numTexCoordStreams = 0;
            for (var ii = 0; ii < streams.length; ++ii) {
              var stream = streams[ii];
              if (stream.semantic == o3djs.base.o3d.Stream.TEXCOORD) {
                lastTexCoordStream = stream;
                ++numTexCoordStreams;
              }
            }
            // Add any missing TEXCOORD streams. It might be more efficient for
            // the GPU to create an effect that doesn't need the extra streams
            // but this is a more generic solution because it means we can reuse
            // the same effect.
            for (var ii = numTexCoordStreams;
                 ii < numTexCoordStreamsNeeded;
                 ++ii) {
              streamBank.setVertexStream(
                  lastTexCoordStream.semantic,
                  lastTexCoordStream.semanticIndex + ii - numTexCoordStreams + 1,
                  lastTexCoordStream.field,
                  lastTexCoordStream.startIndex);
            }
          }
        }
      }
    }
  };