message: demo: Add color based on intensity to UV charts
  This makes them a bit nicer.
diff: @@ -157,9 +157,12 @@ void display(int width, int height, const Mesh& mesh, const Options& options)
  {
  const Vertex& v = mesh.vertices[mesh.indices[i]];
  + float intensity = -(v.pz - centerz) / extent * 0.5f + 0.5f;
  +
  switch (options.mode)
  {
  case Options::Mode_UV:
  + glColor3f(intensity, intensity, intensity);
  glVertex3f((v.tx - centeru) / extentuv * scalex, (v.ty - centerv) / extentuv * scaley, 0);
  break;
  @@ -174,7 +177,6 @@ void display(int width, int height, const Mesh& mesh, const Options& options)
  break;
  default:
  - float intensity = -(v.pz - centerz) / extent * 0.5f + 0.5f;
  glColor3f(intensity, intensity, intensity);
  glVertex3f((v.px - centerx) / extent * scalex, (v.py - centery) / extent * scaley, (v.pz - centerz) / extent);
  }
  