DirectDraw vs D3D for native resolutions. Aarons view.

[AndyWarne]

On another thread there was a debate about not being able to use D3D for native resolutions.
To recap, when running a game which "almost" fits one of the native resolutions on the ArcadeVGA card (or whatever other method being used), when in D3D mode the game will be stretched to fit. This means one or two pixel-rows will be duplicated. As the pixels at these resolutions are large, this renders the screen distorted.
When using DirctDraw, this does not happen. The game screen is automatically centered on the screen with small borders inserted as required, which are not noticeable. The game screen runs pixel-perfect.
There is a view that D3D is better (apart from this issue) in that it is faster, but I am not sure this is correct because at these low resolutions, and without any stretching, the video API, drivers and card are having to do very little work.
I mentioned this to Aaron and he seems to have the same view as follows:

Quote:
The reason D3D doesn’t work is that I specifically designed it not to work for the fixed resolution case. I don’t see any advantage to using D3D when you are not doing any scaling, and it complicates things to make it work.
I’m curious why people want to use D3D with the AVGA? If I hear a convincing argument, I can be swayed,  but I want to understand the logic.

I don't disagree with what he says. But over to the assembled audience, any other views on this?
Andy

[Howard_Casto]

Well my agument would be that if you use d3d you don't have to scale.  Set your resolution to the highest your arcade monitor will handle and you are done.  Assuming the d3d scales properly of course.  Because d3d is what newer cards support and ddraw is virtually dead, d3d is quicker in this respect.  Also those un-noticable small borders, on some games are very noticable.

I think that is the misconception.... many people assume that users want to run the games in their original resolutions.  This isn't true.  We want to run them in such a way that they look arcade perfect (or close to it) with as little effort as possible. 


With that aside, the reson people have a problem with ddraw is two-fold. 

1.  There are sound issues.  That is what that other thread was about.  I can attest that the new -speed flag does little to help it. 

2.  Those borders can get really big on certain setups.   Of your arcade monitor/video card combo is capable of a very close resolution then it isn't a big deal, but this isn't always the case.

The thing is d3d works really well and all of it's options work well and ddraw, simply put, does not.  It's not necessarily the fault of the two protocols/libraries but maybe how mame uses them.  I honestly don't know enough about mame's rendering system to tell.

Slightly different from what others may be facing, but just as an example.  I've got a dual monitor setup, with one of my monitors being a hacked psone screen that runs at a fixed resolution of 640x480 interlaced only.  The video card running it, for cost reasons, is an old matrox card.  It is so old it can't run d3d so for dual screen games I have to run both monitors in ddraw mode.  Well, punchout, for example has a very low screen resolution so on both of my monitors I have a border of around 10-20 percent around the gameplay area which is just unacceptable.  I can stretch it, with hwstretch, but the hwstretch in ddraw is so poor that it blurs the screen very badly.  In either case when ddraw is enabled, even with no hwstretching, regardless of if I even use the secondary monitor, I loose about 10fps and the sound stutters badly.  Mind you this happens even if the matrox card is turned off and I only use my primary screen and I don't have hwstretch on (which leaves a huge border).  Now all I have to do is switch to d3d and the problems are solved.  The game fills the whole screen with hwstretch turned on and it doesn't blur the image at all.  I also get the full framerate.  Of course I can't use d3d though if I want to use my secondary screen.  So I'm stuck, I have the option of either having a wierd display with bad framerates on two screens or a pefect display on one. 

This is the issue a lot of people are running into, namely we'd use either one if it worked with our hardware setup but as-is neither does.

I wasn't even aware the problem was so bad until that thread came up and I started doing testing.  I had always assumed the framerate drop when using dual monitors was due to the fact that the card I was using was a pos until I went back and tried several options.  Turns out it's just mame doing it.

[AndyWarne]

Well my agument would be that if you use d3d you don't have to scale.  Set your resolution to the highest your arcade monitor will handle and you are done. 

Absolutely cant agree here Howard.
This will result in a terrible picture.
If you really mean the highest resolution a standard-res arcade monitor will handle, thats 640 X 480 interlaced. Forget about anything resembling an arcade picture with an interlaced screen.
Or maybe you mean non-interlaced, ie 320 X 240. (well most arcade monitors will handle up to 288 lines but theres not going to be a great deal of difference). Running all games at 320 X 240 using any available scaling method will also be poor.

In the situation you mention you are forced to use scaling because you only have one resolution available. So in that situation there is little doubt that D3D is better, although the picture must be poor with any method.
If you have a range of approx 30 low resolutions to choose from, then most games are a very close fit and can run with very small borders. The ones which don't fit can be run with scaling (ie D3D) but the majority look far better if run native with borders ie DDraw than they do with scaling (using DD or D3D).  The difference is night and day.
As an aside, your monitor might well be capable of non-interlaced arcade resolutions presumably. It must be a 15Khz monitor so no apparent reason why not.
Any interlaced screen is not going to be arcade-real.

Andy

[headkaze]

The issue isn't so much that DD is dead which it is as a supported API by Microsoft. It's the fact that video card manufacturers have dropped adding support for Direct Draw in their video drivers.

A case in note is that GameEx runs in Direct Draw. I have Catalyst drivers from 2005 for use with my Radeon 9800 Pro. If I install the latest drivers (which I tried the other day) things like alpha blending in DD is so slow you can count seconds between each rendered frame. I obviously had to go back to using the older driver.

Also people are experiencing sound stuttering (which the old post was about initially) when using Direct Draw. Explain to me why this problem dissapears when they change to using Direct3D?

So I have to agree with Howard on this point. But it's hard to know exactly what combination of hardware/drivers/software is causing the issues people are experiencing.

[Space Fractal]

Any plans to convert MAME to use OpenGL instead the slow DirectDraw?

Yes I noticed it while I developed MultiJuke.

I'm using BlitzMax to develop MultiJuke and also have noticed DirectDraw was painfully slow in Vista. I have since the lastest version of MultiJuke needed to change the default driver to OpenGL, so it could run MultiJuke at full speed again, due DirectDraw only could run about 1/3 speed and lagged very much....

So DirectDraw is dead now in my eyes and is not even supported by Microsoft since DirectX7. So here I have to agree with Howard in that point.

[Howard_Casto]

Absolutely cant agree here Howard.
This will result in a terrible picture.
If you really mean the highest resolution a standard-res arcade monitor will handle, thats 640 X 480 interlaced. Forget about anything resembling an arcade picture with an interlaced screen.
Or maybe you mean non-interlaced, ie 320 X 240. (well most arcade monitors will handle up to 288 lines but theres not going to be a great deal of difference). Running all games at 320 X 240 using any available scaling method will also be poor.

In the situation you mention you are forced to use scaling because you only have one resolution available. So in that situation there is little doubt that D3D is better, although the picture must be poor with any method.
If you have a range of approx 30 low resolutions to choose from, then most games are a very close fit and can run with very small borders. The ones which don't fit can be run with scaling (ie D3D) but the majority look far better if run native with borders ie DDraw than they do with scaling (using DD or D3D).  The difference is night and day.
As an aside, your monitor might well be capable of non-interlaced arcade resolutions presumably. It must be a 15Khz monitor so no apparent reason why not.
Any interlaced screen is not going to be arcade-real.

Andy

No I didn't mean interlaced, as interlaced isn't a "real" resolution in my eyes.  I did say "assuming scale mode is working properly" if you'll go back and read.  If it was wrote differently or a different technique was used the scale method could be improved.  I mean I don't pretend to know what's going on with mame, but my fe, which is wrote in d3d can scale an image at a very small resolution up or at a very large resolution down with little to no distortion. It can take the same skin and run it in multiple resolutions as well, even very low resolutions and the layout still looks really good considering. I'm sure the same thing could be done in ddraw as well though, I'm not playing favorites in that aspect.  And I think that you think I don't get what you are saying but I do.  At very low resolutions, having one line off can lead to a lot of distortion.  It basically has to do with not being able to divide/double the resolution evenly, which I get.  You would really be amazed though at how well d3d can scale things with the right filters and scaling techniques.  If nothing else then the ddraw method of inserting lines could be used and at least that would be future proof.  Again, I'm not sure what is going on inside mame, but I figure since I'm not that good of a programmer and I can find solutions to this type of problem surely aaron can think of something.  

Actually I have a lot of trouble with borders with any arcade monitor, not just that one situation.  Just as an example my gorf cab has issues with certain games about clipping, offset and border size even when it's restricted to only vertical games (which it always is).  See the problem isn't 90% of the games, it's that last 10 percent.  The only way to play them with the whole screen showing at supported frequencies often involves manually adjusting the trim on the back of your monitor, which basically means you won't be playing those games.  The only way I personally know of solving that is to never change the resolution.  That's why I said assuming we could get a good scale tehcnqiue going this would be the best method, because, from the user's standpoint they'd only need one global setting.  Of course there would be games where you'd have to go back and tweak the resolution manually because they don't scale well, but having a good scale could solve a lot of problems, especially on those odd-ball games we've both mentioned.

It's your opinion that the games look better with borders, but it's my opinion that I'd rather them look slightly worse and have them fill the whole screen.  I agree though, for most of your games the border is so small, if existant that it isn't a big deal.  Like I said though, it's that last 10% that'll get ya.

I hope this doesn't come off as me arguing, I just get the feeling that you are dis-missing some of what I am saying because you don't think I know what the issues involved with scaling at low resolutions are.  I hope some of this is helpful in figuring out what needs to be done.

[Cakemeister]

Any plans to convert MAME to use OpenGL instead the slow DirectDraw?

Try SDLMAME. SDL uses OpenGL.

[ahofle]

Aside from the sound issues with ddraw, I find that it's VERY difficult to get rid of screen tearing for whatever reason.  Even when my monitor is running at the exact resolution/refresh rate of the original game.  If I enable 'sync monitor to refresh' I get stuttering, and if I leave it off I get tearing.  I just don't get it.  The VS games are a good example of this - I run them at the exact arcade resolution with ddraw  (256x240 at 60hz) and I still get tearing in Excitebike.  Why is that?

I'm a bit surprised Aaron is asking this actually.  I thought a while back he yanked ddraw support from MAME and only reluctantly put it back after people bitched.  The fact that it is a deprecated API and mamedev wanted to get rid of it was one of the main reasons I wanted to switch to D3D.

[AndyWarne]

Some good points here and I will pass some of the highlights on to Aaron.

Howard I don't have the view that you are arguing at all, this is what healthy debate is about which is why I started this thread.

But, I am interested to know what you have in mind. Take an example, a game which runs at 320 X 225 and you want to run it at a fixed resolution of 320 X 240. How would you scale this? You have to add 15 rows of pixels somehow (ie 15 lines). theres no escaping that fact. Theres no other way to do it. You cant split them evenly over the screen. 15 of the lines need to be doubled-up. So the perfect scaling method which you mention is purely hypothetical.
Andy

[ARTIFACT]

in a D3D-only world, it would be possible for a good gpu coder, using HLSL or other pixel hader language, to write a set of shaders that emulate exactly the way dots look on old cga/ega/etc monitors

(see my project thread, page 4, enlarged versions of the dig dug screenshots with true rgb dots etc ... something i've yet to see on anything other than true native res multisync tube monitors)

in this type of situation (GPU pixel shaders), the highest the resolution, the better / most realistic the effect would be

i have yet to hear about somene doing this, but i predict it will happen unless it has already and i missed it.

this would be a whole chain of complex pixel operations done on the GPU on every frame. DX9 card or better would be the requirement. this is similar to how recent games generate sun 'bloom' on cars (etc) in real time. it is procedural and handled by the GPU. it is a very different model than the previous all pre-mapped lighting and rendering model.

have you heard of existng efforts along these lines?

[headkaze]

in a D3D-only world, it would be possible for a good gpu coder, using HLSL or other pixel hader language, to write a set of shaders that emulate exactly the way dots look on old cga/ega/etc monitors

(see my project thread, page 4, enlarged versions of the dig dug screenshots with true rgb dots etc ... something i've yet to see on anything other than true native res multisync tube monitors)

in this type of situation (GPU pixel shaders), the highest the resolution, the better / most realistic the effect would be

i have yet to hear about somene doing this, but i predict it will happen unless it has already and i missed it.

this would be a whole chain of complex pixel operations done on the GPU on every frame. DX9 card or better would be the requirement. this is similar to how recent games generate sun 'bloom' on cars (etc) in real time. it is procedural and handled by the GPU. it is a very different model than the previous all pre-mapped lighting and rendering model.

have you heard of existng efforts along these lines?

I mentioned pixel shaders in the previous thread related to this one. I believe they will be used in Mame in the future.

[wpcmame]

>I’m curious why people want to use D3D with the AVGA? If I hear a convincing argument,
>I can be swayed,  but I want to understand the logic.

Artwork crop doesn't work with DirectDraw.

I have my monitor configured to show ~280/560 lines (perfect for vertical and vector games). This means that I get borders around most games. Its to bad that I need to compile my own mame with a D3D patch just to fill these borders with artwork.

>Any interlaced screen is not going to be arcade-real

We can probably debate arcade-real forever but the only difference with interlace is the scanlines. Personally I don't miss them and the artwork looks so much better without visible scanlines.

[AndyWarne]

Artwork crop doesn't work with DirectDraw.

OK another one for Aaron!

I have my monitor configured to show ~280/560 lines (perfect for vertical and vector games). This means that I get borders around most games. Its to bad that I need to compile my own mame with a D3D patch just to fill these borders with artwork.

>Any interlaced screen is not going to be arcade-real

We can probably debate arcade-real forever but the only difference with interlace is the scanlines. Personally I don't miss them and the artwork looks so much better without visible scanlines.

The main difference is the flicker that the 30Hz refresh of alternate lines causes. Arcade games would not flicker like this. Possible exceptions might be some projection screen games.

[Howard_Casto]

>I’m curious why people want to use D3D with the AVGA? If I hear a convincing argument,
>I can be swayed,  but I want to understand the logic.

Artwork crop doesn't work with DirectDraw.

I have my monitor configured to show ~280/560 lines (perfect for vertical and vector games). This means that I get borders around most games. Its to bad that I need to compile my own mame with a D3D patch just to fill these borders with artwork.

>Any interlaced screen is not going to be arcade-real

We can probably debate arcade-real forever but the only difference with interlace is the scanlines. Personally I don't miss them and the artwork looks so much better without visible scanlines.

Haven't you been listening?  Video cards are phasing out, ddraw and as of now most newer cards preform poorly or not at all in ddraw mode.  As much as I like the AVGA it isn't the only way to display mame on an arcade monitor anymore, with tools like powerstrip and soft 15kz.  And on top of that ddraw basically isn't working anymore on many people's systems, causing stuttering in the sound (extreme stuttering) regardless of the pc's specs or the video card used.  So bascially it isn't a matter of one preference over the other, it's a matter of not having a choice.

To summarize what we've talked about so far, basically you have your choice of d3d, in which older cards aren't supported, stretching works, artwork works and the sound doesn't skip but scaling doesn't work well or ddraw, which might not even work on your setup, doesn't support artwork well, skips the sound and stretching doesn't work well.

So atm, both are essentially "broken" (and I hate to use that word) and atm having either option fully functional would be great.  In the long run, however, it might be best to give d3d the functionality that it lacks from it's ddraw partner as, eventually ddraw won't be supported on cards at all or at least not at a level that would result in a playable game.  That doesn't mean to get rid of ddraw though, because, unfortunately older cards won't support d3d at all. 

At this point it's more of a matter of inproving the functionality of both rather than choosing sides, at least imo.

And just for the record, I love the new artwork system... then again my primary mame cab uses a tv. 

[wpcmame]

The main difference is the flicker that the 30Hz refresh of alternate lines causes.
Arcade games would not flicker like this.

Flicker is only visible if there is a contrast difference in alternate lines.
If a low-res arcade game is double-sized, the odd and even lines are exactly the same and there is no flicker.

Several arcade games (e.g. tapper and popeye) originally used interlaced display and didn't flicker (except where  intentional like the popeye bee-nest)
[/quote]

Haven't you been listening?  Video cards are phasing out, ddraw and as of now most newer cards preform poorly or not at all in ddraw mode.

I Don't understand that comment? I use D3D with my own cleanstretch patch and it works fine also with artwork.

[Howard_Casto]

Exactly man, your patch isn't in the official build, so not everybody has the luxury.

And as we've said several times, ddraw, even with the avga is causing sound issues, so it isn't a matter of wanting d3d, it's just that ddraw isn't working!

[Minwah]

The reason D3D doesn’t work is that I specifically designed it not to work for the fixed resolution case

Seems to me the obvious answer would be to give the option to use D3D at fixed resolutions.  Perhaps I am missing something but surely a newer 'better' system should be able to do something an old almost defunct system could do perfectly well.

[Howard_Casto]

Agreed.  With that being said, if aaron were to take out the ddraw renderer, half of the scene would have proverbial cow because their 10 year old video card is no longer supported.  Because of that he'd probably wanna at least fix the current sound issues in ddraw as well.  ;-) 

[ahofle]

I personally doubt he'd get much fuss dumping ddraw eventually as long as D3D became a complete, accurate replacement.  The people with 10 year old video cards are probably using older versions of MAME anyway.

[Space Fractal]

DDraw is defunct now, since Microsoft deprecated it since DirectX7 and they have only keept it in DirectX paths for backward combatible only in many years.

But why can Aaron not put in a officiel OpenGL driver instead? It does have not have any lagging issues like DrawW have, and is much faster in Vista (MultiJuke example suffer a lots with DDraw driver in Vista).

So if you ask me, Aaron should remove DDraw driver pernament, but instead change it to OpenGL in the officiel MAME. OpenGL exists to other platform as well (like Linux and MAC), so it should been easier to mainstream.

OpenGL ran perfectly when I tested it here, and its required pixel perfect picture, but you can still use hardware scaling, if you want to do that.

This may discard for use with older graphics card, but you can today get a very cheap ATI/NVIDIA graphics card with OpenGL support. So I cant see the problem with these 10 years graphics card? Whould they even run a decent version of MAME with a new machine with a old graphicscard? Here a older mame is better for older machines.