[Resolved in TDM 2.06] Will there be a 64bit engine?

[MirceaKitsune]

First of all, hello! I am a new player and user, who sadly only heard of TDM a few days ago. I was mind blown that a game of this genre + quality + complexity might exist in the world of open-source / Linux gaming, and couldn't believe my eyes until I actually played it and looked for official info on the website. Thank you to those who created this fantastic and ambitious project, and of course ID Software for releasing the Quake 4 engine which made it all possible. As far as I'm aware, this is the only FOSS singleplayer FPS, as well as the only FOSS project with cutting edge rendering features which actually allow for modern visuals... certainly something new in this area.

 

There are many things I'm intrigued to discuss and possibly suggest. I wanted to start with a simple technical question however: Is it known when there will be an x64 version of the engine? 32-bit is always slower more or less, as well as limited to 4GB of memory... main reasons why I strive to run only 64-bit versions of everything. It's also problematic to run on a 64-bit Linux OS, where you usually need compatibility libraries to be maintained. I use openSUSE which thankfully maintains these... but I still have an issue with sound constantly "flickering" and suffering rhythmic interruptions, which is suspected to be related to 32bit.

 

I discussed this briefly on the IRC channel, but only heard that attempts to make the engine x64 compatible existed yet none were finalized. Was hoping there might be more news on what to expect.

[nbohr1more]

A 64-bit engine is on the roadmap and we already have a prototype internally. The next release will still be 32-bit because the 64-bit build

will need heavy regression testing and we are very close to the v2.03 release window.

 

64-bit doesn't always guarantee performance by the way. It's probably way down the list of things that would improve performance below,

moving more work to the GPU, CPU threading, and just generally profiling and optimizing. That said, I certainly understand your frustration

about mixing 32-bit apps in 64-bit Linux. Taaaki has helped a few Linux folks with those problems by supplying custom builds or compile advice

as I recall.

[MirceaKitsune]

Thank you for the info! I know that 64 bit over 32 bit doesn't always improve performance visibly, or does so by a small amount in only specific areas... still a good thing however.

 

As for moving more code to the GPU, I hope that doesn't require openCL or a version of openGL greater than 3.1. I use the free video drivers for ATI (MESA / Gallium) over the proprietary one (fglrx), and it tends to have issues with some complex code. So far TDM works perfectly with it, and FPS is as high as I'd expect it, although it could of course be even better.

[bedhead]

Mirceakitsune, I dont want to derail but what video card are you using? I tried the FOSS drivers with my 7870 and got a black screen on main menu. I didnt know TDM works with non proprietary drivers

[nbohr1more]

bedhead, I think you still need the 32-bit S3TC libraries if you are using an FOSS driver. That was the last I heard of such

a problem.

[MirceaKitsune]

Mirceakitsune, I dont want to derail but what video card are you using? I tried the FOSS drivers with my 7870 and got a black screen on main menu. I didnt know TDM works with non proprietary drivers

 

Radeon HD 6870. But I heard that MESA had issues supporting 7xxx and 8xxx in the past, and was only guaranteed to work properly with 6xxx cards. I'm not sure if that's still the case with latest MESA version, 10.3.

 

I'd like to know when the latest ATI cards will work well with the free driver, since I'd like to not upgrade my video card until I'm sure. Since I'm clearly into TDM, it would help to know when it works with an 7xxx or 8xxx card.

Edited December 19, 2014 by MirceaKitsune

[bedhead]

There are no 8xxx radeon cards. Last i checked, the 7xxx cards and the 2xx rebadge cards are already as good as the older 6xxx. But if you're using FOSS drivers, theres no point to "upgrade" your card.

[motorsep]

All SIMD optimizations in the engine are done for 32bit arch. All existing 64bit forks of idTech 4 have no SIMD optimizations (only a generic one) working. The entire physics and collisions systems are not designed for 64bit either.

[MirceaKitsune]

All SIMD optimizations in the engine are done for 32bit arch. All existing 64bit forks of idTech 4 have no SIMD optimizations (only a generic one) working. The entire physics and collisions systems are not designed for 64bit either.

 

Ouch... I hope that won't pose a problem, and that they can be adapted at some point. Physics at least sound like something that shouldn't be too architecture dependent, but I never worked with idTech 4 so I'm not an expert. 32bit support will be eventually going away I believe, and I hope TDM will still be around and as lively by then.

[motorsep]

Floating point precision is arch dependent (collisions for sure, not too sure about physics), and SIMD intrinsics are not the easiest thing to deal with - it's almost like ASM.

 

Why would you need 64bit engine? Not everyone any time soon will be on 64bit OS. The only advantage is ability to use more RAM. Have you played RAGE, Crysis 3, Dishonored? I doubt TDM has more assets (and more tris) than these games, and yet those games ran in 32bit (or 64bit but 4GB of RAM) just fine.

 

There only way you absolutely need 64bit is that you have so many assets of such complexity, that your game requires 8Gb of RAM.

[MirceaKitsune]

32bit libraries have to be installed and maintained separately for Linux... which can sometimes be a problem, especially when compiling the engine yourself. There are many threads about Linux users having issues running x32 software on x64 OS'es. 64bit could also be faster in some areas, which I know it doesn't mean performance magically getting better in all regards but still.

 

I additionally imagine that 32bit could stop being supported on some Linux distributions or even some hardware within the next 10 years, and a 64bit engine could become a requirement for people with a modern computer. It is after all an outdated architecture which nearly all ongoing programs have replaced by now (still offering both 32bit and 64bit versions).

 

I also suspect that some issues with sound getting cut off are 32bit related. Currently I need to run TDM via the "aoss" wrapper... and if I press esc to go to the main menu while in a game, the sound becomes a mess and I need to restart. I searched about the problem, and from what I understand it might lie between PulseAudio and the architecture.

Edited December 20, 2014 by MirceaKitsune