I think it is kind of funny in a way I had set up unix.superglobalmegacorp.com years ago, but moved hosts a few times, and it broke all the CGI functionality. But all the static pages still worked, so when googling around for internal stuff related to Quake, I would actually find my old site in the top five.
So, I thought I’d take some time, and get it working again. I use two programs CVSweb, and src2html.
CVSweb let’s you easily explore multiple revisions, do comparisons between the versions, and just look all around great. I keep a copy of the following:
Net/2 This also includes Net/2 derived OS’s 386BSD 0.0 and 0.1, and NetBSD 0.8/0.9
I also like how the src2html program parses out the code so you can search for symbols in the code. However src2html works with static versions of the code, not CVS, so I selected various programs to be available, some from above, and:
So it may not be worth much to most users, but when looking to see how various code works, it’s really useful. Of course none of this compares to Visual Studio’s search database, but google has to learn from somewhere.
Since the last update we got some help in a few fields that have really fleshed out this ‘experimental’ port into a full fledged port. First RayerR helped us with the fun of getting us onto the latest deployment of DJGPP, 2.05 (rc1). It’s always nice to be in the latest available release. Next in a passing comment, Ruslan Starodubov had mentioned that he had gotten a much older build of our QDOS to support the Intel HDA sound chipset via the MPXPlay sound library. I wrote to the author of MPXPlay, Pádár Attila asking for us to distribute his source in our project, and he granted permission.
So at this point things were looking good. The only ‘feature’ that modern OS’s really held over us was the ability to dynamically load and unload game modules on the fly. I had tried to use DLM, but it stripped the DPMI functionality out of the MS-DOS Extender making the port really useless. I tried to build the newer DXE3 support but had no luck. I suspect now my native tool chain was interfering with the build process. But Maraakate managed to get it to not only build, but to run!
Adding in DX3 support was relatively painless. I first looked at DJGPP’s FAQ and downloaded the example code. In the example code there was small helper functions to make unions and check the symbols. If they didn’t exist a printf was spit out to alert you about it. To resolve the issue you simply just add DXE_EXPORT to the other list of missing exports.
Compiling the game code was easy, again referring to the example I saw that basically they compiled it the same, but at link time you use DX3GEN and -U flag to ignore unresolved symbols.
The biggest head scratcher was the Sys_GetGameAPI failing to find GetGameAPI from the DX3. After some piddling around I noticed that it listed GetGameAPI as _GetGameAPI inside the DX3 itself. I added the underscore and it worked!
Other things that were relatively to easy to import was R1Q2’s HTTP downloading code. Compiling CURL was kind of tricky because of the linking order, but thankfully neozeed figured it out quickly.
All of Yamagi’s Quake 2 updated game DLLs were all diff’d by hand using BeyondCompare to make sure I didn’t clash using some newer functions that weren’t available in DJGPP. I also merged their Zaero code with their baseq2 code by comparing Zaeros code to the Quake 2 SDK, marking every thing that was changed. The result is a really stable Zaero game code. If you haven’t played Zaero check it out. I think it’s a lot better than Rogue, but Xatrix is probably my favourite (even over stock Q2).
Other cool things I’m glad to get into the code was the GameSpy Browser. It took me quite a bit of work to get it where it is, but it’s really nice to just be able to ping to a master server (a custom GameSpy emulator I wrote specifically for Q2DOS. Source is not finalized yet, but will be available soon for those curious), pick a server and go! All in DOS!
So here we are at the end of the journey. Or at least safe enough for a 1.0 release.
To recap, we have:
* SVGA (LFB modes only)
* SoundBlaster and Gravis UltraSound Family
* CD-ROM music
* OGG music
* Networking (You need a packet driver)
* Loading/unloading game DLLs in DX3 format.
* Intel HDA support -hda
* Mouse wheel support with -mwheel
But it doesn’t work. Well for me. But rest assured that the other drivers work, and even better it feels that the dynamic support has gotten faster, and some faster Pentium models have even been thrown into the deal!
Well it mostly works now. But did we ever have the biggest fun with the sound and SVGA.
So [HCI]Mara’akate integrated all the Q1 sound code, got it to compile, but nothing not a peep from the sound card. While I was busy trashing the video code, he spent way too much time on the audio, and then for the heck of it I thought I’d look at the code, although I’m really stabbing in the dark when it comes to audio. Imagine my surprise when I compiled the code, and ran it and got the sound blasting at full volume! It turns out that I had my audio set to ‘high quality’ in the client, while he had his set to ‘low quality’. What it does is govern the frequency between 11Khz and 22Khz. And if you get this wrong you get *NO* audio. OOPS. At least it was one of those feeling vindicated moments that his efforts for sound really did work.
Now with audio, it was my time to hurry up and get the video going. I had basic VGA working so I figured I didn’t want to spend a lot of time on this, so I was going to go with the VESA 2.0 linear frame buffer. Well this once more again proved to be a bit more involved as the only way I really have to test is emulation via DOSBox and Qemu. And naturally both of them worked fine, but when [HCI]Mara’akate ran it on his real DOS Box (with GUS of course) it crashed wonderfully.
Now I had taken the VESA init code from Quake 1 to build a table of what 8bit modes are supported, and used the VESA code to switch, along with drawing to the buffer with a simple memcpy. And we got nothing but crashes.
After looking more around, I found that you had to add 0x4000 to the VESA mode you want if you wanted to access it’s LFB. Did that work? No still crashed.
Later in the adventure we noticed to get proper access you had enable ‘near pointer acess’ with a call to :
So naturally I would disable it when I’m done, making the call look like this:
WRONG. Oh so WRONG. Well OK technically it did work, but if sound is enabled (and why wouldn’t it be?) it would immediately crash with an error in the DMA code. We ended up wasting over a day trying to figure this one out until I just said screw it, let’s never dsiable the nearpointer, leave it unprotected. Naturally that actually worked. The hint is in map_in_conventional_memory, where __djgpp_nearptr_enable(); is called, but of course there is no calls to __djgpp_nearptr_disable(); I’ve thought about going back through the source to ‘clean’ it up to make it lock and unlock memory as needed, but this is 2015 not 1997 so good enough is well, good enough.
So now with VESA and Sound, I thought this would be a great time to tackle the dynamic loading of gamex86. We will have to re-compile whatever gamex86 DLLs are out there as of course DOS is DOS. The HX DOS guy Japheth seems to have died, as his site and all the info on that extender seems to have mostly vanished. I have an old copy, but I never could make it call DOS stuff if you had WIN32 stuff going on. And if he’s really dead it’s too late to ask him.
Ages ago I remembered this DLL support for DJGPP called DLM, so I thought I’d give that a try. I was able to take our ‘null’ version of Quake II, and get it to where it can load and unload the gamex86.dlm at will. So I figured this was going to be an easy win, right?
Wrong again. Once I started to put in the MS-DOS specific code I got this fun crash:
DLM -> Exiting due to signal SIGSEGV at
0x0014f59d SYM: _dos_lockmem+0x9 DLM: q2.exe [0xf5000]
possibly because of undefined reference to symbol ‘___djgpp_base_address’
So apparently it doesn’t export (or import) djgpp stuff like the base address calculations so we can’t do direct memory access, which means no video and no sound. Ouch. I’ll have to hit the lists to see about support. I don’t like the DXE’s because they cannot be unloaded, so that isn’t much good. And of course things like the JVM inside of gamex86.dll is right out as JAVA inside of MS-DOS? in 64MB of RAM? Dream on.
So for now, the gamex86.dll is statically linked into the executable. You are restricted to vanilla gameplay for now.
As an added bonus, I used Rufus 2.2, to setup a bootable MS-DOS USB stick, slapped everything onto there, and booted up on my Xeon, and it works!
Now as a super bonus, [HCI]Mara’akate went above and beyond by adding in a bunch of fixes, and updates from 3.24 and varous stuff from Knightmare. And then the best part is integrating libogg, so it can now play the ogg sound track! Really, just place the ogg files in the baseq2\music directory and away you go!
Continuing in this series on porting Quake II to MS-DOS, we get to touch some of the fun stuff. The first big ‘fun’ thing is networking.
Now in my prior work with the MS-DOS version of Quake, I had used the WATTCP library to bring networking to the otherwise Windows/UNIX specific fun of network deathmatch back to MS-DOS. Quake by default had support for the Beame & Whiteside’s TCP/IP stack which for all intents and purposes has vanished from the face of the Earth (does anyone have a copy?!). So at the time, I thought it’d be cool to try to interface WATTCP with Quake, and it worked on the first attempt as WATTCP is a very competent TCP/IP stack.
So I took the Linux networking file net_udp, and compiled it, and I got an executable!
When it comes to testing WATTCP though, I prefer to use Qemu instead of DOSBox as it can not only emulate various network cards to which I can find packet drivers (yes even the evil PCI NE2000!) but it has a built in SLiRP network stack that let’s me NAT on my desktop without any crazy network configs.
And for the sake of testing, I setup a ‘null’ text mode server, figured out some flags, and I was able to connect!
Very exciting stuff indeed!
Now for some interesting stuff. First I noticed that MS-DOS 5.00 with himem.sys is almost unplayable because it is so slow. MS-DOS 4.01 without himem.sys is actually faster. No, I’m not kidding.
Next is that some levels LOVE to gobble up RAM. Maps like city1 will need at least 192MB of ram. I haven’t even tried playing with the virtual memory of DJGPP, and I really don’t want to. And let’s face if, if you even try to load Quake II on a MS-DOS machine, it better be a ‘big’ one. This means you should be using the ‘dos’ from Windows 98, or perhaps FreeDOS, although I haven’t tested that at all.
So far from our limited testing the networking seems to be pretty good. And at least that is one function we didn’t have to really pour a lot of effort into. Although the payoff of being able to connect to servers on the LAN and even the internet is a good thing.
(In this series, I’m going to go over the process of porting Quake II to MS-DOS. Now of course the question will pop up why? And the answer is simple enough, after [HCI]Mara’akate added in gamespy support, something was noticeably off, and that is fewer and fewer people are playing Quake 1 these days. So what to do?
Well apparently Quake II has an active following, so it’s time to move our creeky but favorite OS, MS-DOS into the Quake II Arena!
So the first thing to do is to grab a copy of the GPL source to Quake 2, along with a copy of the game, and get started on making a ‘null’ version of the game. Null versions of the game have no graphical output, no sound, and ‘function’ at a very basic level. It’s something to strive for as a first base in hitting that home run of a functional port. Thankfully iD wrote really portable and modular software. Unfortunately they tended to let their ports drift as they were writing the engine so the null code doesn’t actually work out of the box. And the project makfiles leave a little to be desired for me, as they have a bunch of i386/Dec Alpha magic which doesn’t leave much in the room for weird ports like MS-DOS.
Now I should mention that before I’d gotten started the first thing I decided that like QuakeWorld for MS-DOS (and OS/2) I would use GCC as it is a known working compiler out of the box. If you can, don’t fight so many battles of unknowns at once. Another thing is that I am going to cross compile from OS X and test with DOSBox. Of course you may want to use something else, and I know my tastes drift, but for now this is what I’m using. I’m using my old OSX to DJGPP cross compiler with GCC 2.95.3, which serves me well.
So the first thing was to compile and run the null version with native tools on OS X. After a bit of struggle I got here:
One thing I did to make it easier to work with the flow of Quake is to make the Sys_Error procedure contain a divide by zero. Now why would I purposely put a divide by zero in the code? Simple it lets me back trace the code when Quake catches it’s own faults so I can see what went wrong where, vs what would look like a clean exit. From my example:
We can see that the vid.width/vid.height aren’t being setup correctly. Turns out there was a bunch more work to be done setting up vid_null!
After looking closer at the files, I notice as I’m stitching them together is that Quake II relies on DLL’s as part of it’s base functionality. I drifted out of Quake after Quake 1, so I never played II before. So I didn’t know this. Obviously DJGPP doesn’t support DLL’s that can be loaded and un-loaded at will (Yes I know about DXE’s, but as the FAQ states, they cannot be un-loaded. And I’m not going to fight DJGPP’s LIBC). So looking further in the source, I saw these fun defines:
So at one point there was support for ‘hard linking’ in the ‘REF’ video driver, and the ‘game’ logic driver. But it did kind of drift out of the code. But looking at the Win32 version I could see that putting this functionality back in should be easy. And to be honest if I learned any lesson from this, is that I should have been pulling the Win32 version apart by injecting null into it until it ran as a null platform, then use that as the basis. Lesson learned. Always start with a known good! Quake II was built with Visual C++ 6, but I only have Visual C++ 4.2 installed on Crossover. Yes I know again this is me being difficult. But it didn’t take much time to get a simple project that has two DLL’s and a Win32 exe running. Then I took on the ‘ref’ video driver and got that linking inside of the main EXE. Now with one DLL ‘eliminated’ it was time to work on the game dll.
The game DLL posed the biggest challenge because it passes a reference to internal functions to it, and exports various functions back to the game engine. So I ended up altering the engine to not call the game import/export directly but setting it up myself. The hardest thing was that I couldn’t pull in the game header file, but rather I had to copy the prototypes myself. Another interesting thing with the way Quake II works is that the game dll has to be able to be unloaded and loaded at will. It wasn’t hard to simulate this, but I wasn’t expecting it. Again this is probably because I never really played Quake II.
Now that I had Quake II building without DLL’s I could then take the next step of removing all the IO and re-replacing it with the null code, and now I had something that looked like it was doing something.
This turns out because I didn’t allocate the screen properly. Looking at the code:
if ((x < 0) || (x + w > vid.width) ||
(y + h > vid.height))
ri.Sys_Error (ERR_FATAL,”Draw_Pic: bad coordinates”);
We can see it pretty plainly.
Now since we were going somewhere I started to write some MS-DOS code, and switch out of the null set of mind!
First a simple VGA mode 13 setup which gives us 320×200 resolution with 256 available colours. And for good measure I did a simple VGA palette setup that I knew worked from a prior program. Next we just blit our buffer onto the screen, and we get this:
Which is exciting and disappointing at the same time. I then took the palette code from DOS Quake, and got something just as ugly. I tried the code from OS/2. Same thing. I tried all kinds of things and was going nowhere.
At this point Mara’akate added in the Linux clock code, and now we had this!
It wasn’t until much more digging around I saw some 320×240 screen setups that I realized there was something wrong there, and then I saw this gem in the linux port’s code:
** System specific palette setting routine. A NULL palette means
** to use the existing palette. The palette is expected to be in
** a padded 4-byte xRGB format.
In traditional VGA palette setups it’s 768 bytes that needs to be read/and pushed to the card. I even checked Quake 1 is 768 bytes, but now in Quake II, it’s 1024 bytes! OOPS! Sometimes (ok a lot of times) you really need to check other ports or a ‘known good’ to see how they did things.
So where to go from here? Obviously things like better keyboard input, the mouse, sound and networking need to be done.