(demo) 3d engine

[(demo) 3d engine]

45 minutes ago, DrTypo said:

In the clipping function, I had code like this:

    load  (r15+CVertexXti),rX
    load  (r15+CVertexYti),rY
    load  (r15+CVertexZti),rZ
    or rZ,rZ
    store rX,(r14+CVertexXti)
    store rY,(r14+CVertexYti)
    store rZ,(r14+CVertexZti)

I had to change it to:

    load  (r15+CVertexXti),rX
    or  rX,rX
    load  (r15+CVertexYti),rY
    or  rY,rY
    load  (r15+CVertexZti),rZ
    or rZ,rZ
    store rX,(r14+CVertexXti)
    store rY,(r14+CVertexYti)
    store rZ,(r14+CVertexZti)

I don't know really why.

If r15 is pointing to main RAM, this is a known bug:

[CD Game Support]

9 hours ago, Indcsion said:

This game works sometimes

Just like on the real JagCD, then.

[Rmac - do the math]

This is not a bug -- this behavior is documented:

 

Workaround: always use explicit parentheses.

[CD Game Support]

I wonder if there would be a need for a tool which would copy files to a SD card while making sure they're not fragmented. (The "lazy" way would be generating a fresh FAT32 file system image and writing it to the card.)

[Jaguar dust flap]

[Jim Power]

I've never played the original game, but it looks like there's also something wrong with the parallax scrolling. Objects on a slowly-scrolling plane shouldn't appear in front of objects in a faster-scrolling plane.

[Jaguar Rgb issues]

Are you sure the monitor is actually set up for RGB mode, not YPbPr mode?

Also check that your cables are connected properly.

[Upcoming Jaguar Game Drive Cartridge]

Fair point.

[Working JagCD price 2021?]

 

[Upcoming Jaguar Game Drive Cartridge]

5 hours ago, samson7point1 said:

if my JagGD gets stolen or ruined in a flood and I replace it then I either can't play that game anymore or I have to jump through hoops to re-authorize it.

I'm not a fan of DRM, but this situation is a pretty rare occurrence. And I think most homebrew developers would send you a "replacement" download for free if you showed them some proof your JagGD got stolen or damaged.

[SoulStar, interest and pricing poll.]

10 hours ago, leech said:

Ha, if you ask about SoulStar they will probably say no, because they are working on a reboot...

...while Reboot is working on SoulStar.

[Working JagCD price 2021?]

8 hours ago, Guillem said:

I think when Jaguar GD takes over CD support, the price will drop.

I don't think so. This has not happened on other consoles.

[State of Jaguar Emulation in 2021?]

That doesn't look like a Jaguar...

[Skunk & Boot ROM]

The boot ROM is 8-bit wide with 10 cycles access time. The Skunboard Flash memory is 16-bit wide with 5 cycles access time.

 

The settings in MEMCON1 affect both, so if you want to read the boot ROM, you need to change the value of this register (from code running in RAM, of course, otherwise it'll crash) and restore it after you're done.

 

Keep in mind that accessing the boot ROM will make your game incompatible with the BJL ROM.

[Memo on testing from Leonard Tramiel]

It's an old classic, but rereading it is always fun and shows how dysfunctional Atari was back then.

 

There were also interesting stories from the developers side:

https://atariage.com/forums/topic/221243-minter-txk-t2k-and-stuff/?do=findComment&comment=3090113

[Cartrige dumping utility : release it or not ?]

17 hours ago, cubanismo said:

I verified I can still upload very large files over this BJL cable successfully in 8-bit mode. Any ideas?

I'll have to check the actual source code -- that thing is more than a decade old at that point...

 

But this is pretty strange. If the BJL uploader works fine on the same machine, I don't see any obvious reason why the dumping code wouldn't.

[Jaguar Dev System]

4 hours ago, cubanismo said:

Any recommendations on a quality bit of cable to use to route the pins from a hat PCB to the 15-pin joystick/VGA connector header? Should I just use some individual shielded wires land bundle them in some heat shrink?

You don't need fancy cable. I made several BJL cables by reusing 15-pin extension cables - the cheap kind with a single piece of aluminum foil over individual thin wires, not the quality VGA ones with several mini-coaxial cables inside - and it works fine.

 

Check that:

- you don't have a cold solder joint somewhere

- the cable isn't too long ; I don't recommend anything longer than 2 meters (~6 feet). If in doubt, try a shorter cable.

- you don't have anything else running which could screw up the timings (BJL is quite picky with that).

- you use proper 3.3 V ↔ 5 V voltage translators (i.e. a dedicated chip, not a resistor/diode based hack).

 

Good luck

(even if I don't understand why you bother with BJL while you have tons of Skunkboards )

 

[Which Skunk JCP?]

You can also open the jcp_installer-02.06.00.exe file using 7-Zip, and extract the jcp.exe file manually.

[Virtual Jaguar accuracy]

#1 is possibly a VJ bug, but margins and picture centering varies from TV to TV (especially on CRT ones), so relying on it is not a good idea anyways.

 

#2 is a consequence of VJ not emulating stuff down to the cycle-level (which would make it even more complex, and slower). So if you want your game to run well in emulation, don't rely on "implicit" timing such as how fast the CPU/GPU/DSP are. Use explicit timing sources such as the VBL and timer interrupts instead, and don't depend on perfect timing accuracy. Even on real hardware, this advice is usually good, too.

 

#3 sounds like an actual bug or limitation in VJ. Try reporting it to @Shamus.

[Which Skunk JCP?]

2 hours ago, cubanismo said:

Auto-detection of serial EEPROM type (128B or 2048B/93C46 or 93C86)

Be careful with that. It involves writing to the EEPROM, which causes it to wear down a little bit, and can also cause data corruption if the Jaguar is turned off right at this moment (unlikely) or if EEPROM contacts on the cartridge slot are a bit dirty (more likely).

 

If you only run the autodetection code when explicitly saving/restoring the EEPROM contents, it's probably fine. But it's not something I'd recommend doing every time you run JCP, or at startup in your game code. (I thought about providing EEPROM size autodetection code for the Jagtopus board, but decided against it for that reason.)

[Jaguar Rgb issues]

Resistors are 0805 size.

 

The ferrite beads are 1206 size. The original part number is Murata BLM31A02, but it appears not to be manufactured anymore. You can use a Fair-Rite 2512067007Y3 instead.

[ST/Amiga Mouse adapter for Jaguar Gridrunner & Defender of the Crown]

Look under your mouse, there may be a switch to choose between Atari ST mode and Amiga mode:

 

To clean it :

https://www.wikihow.com/Clean-a-Mouse-Ball

[Aaron the Aardvark (WIP)]

That. And don't rely on CPU speed for timing ; even on real hardware, it's fragile. Count the VBLs or use a hardware timer instead.

[Jaguar Rgb issues]

Here it is:

 

[Rmac "Warning: RISC code generated with no origin defined"]

The warning is expected in that case, it's documented in the lines just above your snippet:

; NOTE!!!: This code can run in DRAM only because it contains no JUMP's or
;          JR's. It will generate a warning with current versions of MADMAC
;          because it doesn't '.ORG'.