message: temporarily reverting volume instancing due to stall.
diff: @@ -103,7 +103,7 @@ vec4f SciVisRenderer_computeVolumeInterval(const SciVisRenderer *uniform rendere
  float tEnd, float maxOpacity, bool isShadowRay, const varying float &rayOffset, const varying vec3i &sampleID, uniform float quality)
  {
  // ray to model coordinate
  - rayTransform(ray, volume->rcp_xfm);
  +// rayTransform(ray, volume->rcp_xfm);
  // start computation
  vec3f singleCoordinates;
  float singleMax = -1.f;
  @@ -256,7 +256,7 @@ vec4f SciVisRenderer_computeVolumeInterval(const SciVisRenderer *uniform rendere
  intervalColor = make_vec4f(litColor,intervalColor.w);
  }
  // ray back to world coordinate
  - rayTransform(ray, volume->xfm);
  +// rayTransform(ray, volume->xfm);
  return intervalColor;
  }
  @@ -283,7 +283,7 @@ SciVisRenderer_intersectVolumes(const uniform SciVisRenderer *uniform renderer,
  Volume *uniform volume_i = renderer->super.model->volumes[i];
  // ray to model coordinate
  - rayTransform(ray, volume_i->rcp_xfm);
  +// rayTransform(ray, volume_i->rcp_xfm);
  // Intersect volume bounding box.
  float t0, t1;
  @@ -300,7 +300,7 @@ SciVisRenderer_intersectVolumes(const uniform SciVisRenderer *uniform renderer,
  }
  // ray back to world coordinate
  - rayTransform(ray, volume_i->xfm);
  +// rayTransform(ray, volume_i->xfm);
  // Update intersected volume.
  if (t0 < t1 && t0 < volumeRay.t0) {
  