i'm neva using directdraw before. but after reading tuts, i've lots of questions left in my head. they are:

1. is directdraw api can be called from a driver?
2. is directdraw api include as sync or async call?
3. if its realy real time, am i can say that after call directdraw api, at the point the call return, the picture is drawed already?
4. is there any dependency in directdraw api that require a multithreading environment to running?

if anyone knows the answer, help me out, please...
thanks
Posted on 2002-08-21 02:47:52 by dion
Afternoon, dion.

I was waiting for the DDraw buffs to give you an answer, but they all seem to be away on holiday at the moment ;).

I don't use DDraw, however I'll answer the best I can.

1) Wouldn't have a friggin' clue.
(That's a good start to the answers, ay?:grin: )

2) yep. Screen can be updated using vsync, or not.

3) Don't make assumptions like that. Just draw, swap, draw, swap. A lot depends upon the hardware. A lowend PC with a highend vidchip would have displayed the piccy, I suppose.

4) Dunno exactly what you mean. DX is for a Windows OS. Which Windows OS doesn't use multithreading (which can also run DX on it)?

Cheers,
Scronty
Posted on 2002-08-23 21:02:00 by Scronty
wee.. thanks, Scronty.



Dunno exactly what you mean. DX is for a Windows OS. Which Windows OS doesn't use multithreading (which can also run DX on it)?


yep! i know that windows is multithreading OSes. actually the whole point i want to ask is how softice using directdraw for its display driver? i thought if we were in debugging session, another thread should be frozen, isnt it?
Posted on 2002-08-23 21:21:38 by dion
dion: in my experience, under 9x it has always been syncronous, but in 2000 not. Try on the latter to set your process priority as REALTIME, and see that DDraw will stop working..
Posted on 2002-08-24 02:45:08 by Maverick
Well the whole Win OS is not even near realtime, (well maybe Win98 a little)

but AFAIK Directdraw is very close to the video board so it is logical to use it if you want to make lowest level of still hardware independant graphics...

if you need speed you should do what Maverick suggested in an old post: go for the HAL layer interface... but do you really need it?

Anyway you will not be able to make Windows and real time OS, bnecause its design is diferent...

Try Menuet or My SOL OS if you really really need realtime stuff (eh OSX also)

To answer your questions:
Q1: NO ... but the HAL layer could be
Q2:Both ... some functions are in sync some are async some have flags that can change this
Q3:OS is not realtime so how can an application or layer running on top of it be realtime? it can be close on Win98 only
Q4:Yes
Posted on 2002-08-24 12:18:23 by BogdanOntanu
hiya... thanks for all ur reply guys ;)


but AFAIK Directdraw is very close to the video board so it is logical to use it if you want to make lowest level of still hardware independant graphics...


yup! i want that " make lowest level of still hardware independant graphics... ", i think thats the reason why i choose ddraw.


if you need speed you should do what Maverick suggested in an old post: go for the HAL layer interface... but do you really need it?


i'm afraid i'll need that :grin:

checking Maverick's post now.
thanks
Posted on 2002-08-26 21:32:53 by dion
hi, Maverick, i've read ur post titled "Let's go to a lower level in gfx/snd, it's possible." but, it seems theres only disputes everywhere :(. actually, i've read DDraw DDI doc in w2kddk help , but i confused a bit with lot of term there, such as video port extension (VPE), ddraw driver, miniport driver, kernel mode video transport, etc.
do u know what this term mean?

anyway, have u try to do HAL programming? if u had grab the way, maybe u could make an easy-to-understand tut about this hard HAL stuff with source code.

thanks
Posted on 2002-08-27 05:27:24 by dion
Hi dion,

I'm much behind my job schedule, and now I start to feel it like a big trouble.

If I had the time, I'd first fix all issues regarding PROFILE, then release a CPUSPEED routine as unfortunately* I've already announced. Let away that I haven't worked on my new compiler for weeks, and there are many other projects that were expecting my free time.
Posted on 2002-08-27 09:19:29 by Maverick
hi Maverick, sorry to bother u while u'r very busy now. that ok for me, and i agree with all what u said. maybe i'll try to explores more harder.

and have a good work, dont forget to take a breath for a while :alright:
Posted on 2002-08-27 21:24:27 by dion
Thank you and, by the way, you didn't bother me at all.

Please keep us informed on the progresses of your work.
Posted on 2002-08-28 12:19:47 by Maverick