Re: [AD] float positions

[Elias Pschernig <elias@xxxxxxxxxx>]

On Mon, 2007-01-22 at 11:13 -0800, Robert Ohannessian wrote:
> It's not clear what this gets us. Does it allow for things that couldn't
> be done before? Does it simplify user code?

Well, it allows using fractional positions (if OpenGL is set up to make
use of them) for Allegro primitives. As I said, in my case, I could have
directly used e.g. al_blit to move my sprite when e.g. interpolating to
the vsync rate. E.g. if a sprite moves 60 pixels / second, and vsync is
75 Hz, you can't get totally smooth movement without anti-aliasing -
some pixel positions from the 75 different positions in one second are
displayed twice and others only once. If you anti-aliasing so the sprite
can also move fractional pixels, it will look like it moves the same
amount 75 times and be totally smooth.

> Not all blit() paths in AGL can take float coordinates; we do use
> glDrawPixels() after all, so it's not a trivial addition.
> 

Well, in the case of memory bitmaps, I would just limit to integer. I.e.
only blitting a display bitmap to the display would make use of it.

-- 
Elias Pschernig