| Re: [AD] Allegro 5's new graphics core |
[ Thread Index |
Date Index
| More lists.liballeg.org/allegro-developers Archives
]
On Thu, Dec 13, 2001 at 05:13:25PM -0500, Bob wrote:
> ...I'd like to hear your opinions on it.
>
> http://pages.infinit.net/voidstar/new_gfx.c
It doesn't look very good to me. From my little understanding of the 3d
world and accelerated cards, your al_acquire/release_display functions
map the usual start/end_rendering calls of DirectX or OpenGL. Between
these calls, the accelerator is just queuing (slap me for the spelling if
it's wrong) your petitions and all of them _start_ to be drawn with the
release call. Then, the card starts rendering, without stopping your
code, and if you happen to use another al_acquire before the previous
operation has finished, it will introduce the minimum delay until the
hardware can queue again your petitions.
If this is true, don't you notice that all functions regarding video
reads are useless? They simply won't work, because nothing has started
to draw. How would you handle this? Code reading and writting pixels
simply won't work (draw_trans_sprite comes to my mind, along with
drawing_mode(DRAW_MODE_XOR/TRANS) and any affected function).
I think that if your proposal was implemented, not only would you break
backwards compatibility, but some previous games simply wouldn't be able
to port to the new api because of the new restrictions.
> I also disagree with Shawn about not having a GL driver in Allegro.
Do you mean the last document on the web? I think it's fairly clear
that 2d operations don't map with 3d concepts (as stated above, unless
I'm mistaken).
> Although I do agree that 3D is beyond the scope of Allegro, I'd still
> like to use OpenGL's 2D abilities (and acceleration!)
> ...
> Reading back from the screen, although supported, is a slow operation,
> and drawing on the screen may not give the exact same result as if
> Allegro was doing it itself (bluring, filtering and all of that),
> but unless someone is developing Allegro PhotoShop, this shouldn't be
> very important.
Well, you trade quality vs speed. I must say at the moment that Allegro
is not slow, so why would I accept a degradation of my graphics if I
can already draw them fast enough without 3d hardware acceleration?
--
Grzegorz Adam Hankiewicz gradha@xxxxxxxxxx http://gradha.infierno.org/