[musawirali]

That is incorrect. You can cover the screen with a single triangle ... just make it big enough. The corners get clipped and the middle region of the big triangle will cover the screen.

[lotsofmangos]

You can get around the clipping problem by displaying it on an old Interocitor.

[dualogy]

True, both approaches are equally valid and being used. Every once in a while some gfx haxors also spend baffling amounts of effort on humorously "benchmarking" both approaches against each other.. ;)