{: Simple TGLShader based multipass demo.

   This demo uses a custom TGLShader subclass to implement the classic
   multipass hidden lines rendering technique on a torus: first pass renders
   model with filled triangles, second pass does the wireframe.

   You'll also note the glPolygonOffset call, it displaces fragments depths
   value a little "farther away" so that surface fill depth values do not
   interact with the rendering of the lines (comment out the call and you'll
   see).
   The axis and sphere allow you to see the limit of that simple technique:
   it actually "paints" between the lines, so you cannot use it to make
   transparent wireframed objects with hidden lines - if that thought ever
   blossomed in your mind ;)

   Additionnal objects around the show a glow/toon edges effect achieved in two
   passes too: the 1st pass activate lines and gives them a width, the second
   is used to fill the surface (and clear the lines that aren't on edges).
   (TOutLineShader thanks to Delauney Jerome, jdelauney@free.fr)
}
program MultiPass;

uses
  Forms,
  fMultiPass in 'fMultiPass.pas' {FormMultiPath};

{$R *.res}

begin
  Application.Initialize;
  Application.CreateForm(TFormMultiPath, FormMultiPath);
  Application.Run;
end.