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Author Topic: Trevor Raynsford: Programmer and the porter of Zool 2  (Read 25999 times)
Trev
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« Reply #15 on: August 13, 2009, 08:56:29 am »

"The Tempest CD is good, but I prefer to hear the original mods as I play that legendary game."

You know - that's exactly how I felt at the time. We already had the game music - 4 channels, great samples, awesome sound.  But every time I walked past the room where the new guys were making the CD version, I felt they had really muddied and blurred the impact. Just goes to show what a good composer can do.
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doctorclu
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« Reply #16 on: August 13, 2009, 11:16:28 am »

"That's great, forget getting given the assets on disc with a huge doc explaining how everything works - play the game & remake it - that's just great
"


Yes. I had the cushy job with Zool-2. All the (well-written) Amiga source code and assets and a VHS video of someone playing through the entire game.  I used to step through to see exactly how some of the animations were supposed to run and get the sprite placement correct.  The sprite alignment was slightly different between the two machines - I forget why (maybe top-down vs bottom-up?) so I had to change every set of sprite data.  Luckily we had a shiny new VHS player with decent freeze-frame operation.  It was actually used by the team doing some body motion capture work but they let me borrow it occasionally.

That is what is amazing.  They give you Amiga source code and do they give you an Amiga to play it on?  Nooooo..  they give you a VIDEO TAPE of the game.  LOL!   I have made quite a few hours of YouTube videos playing Bubsy...
http://www.youtube.com/watch?v=Q1-LSdrdC-E&feature=PlayList&p=E2CE66EAB305A099

But could not imagine trying to program Bubsy from video stills.  There is so much of the gameplay area that you would not see in a gameplay video.

That is what also cracked me up about Raiden.  At least that one they gave you the freedom of having a arcade game and said "Have at it" but how many times did it take you hours to get to one part (especially later in the game) to say "Oh yeh, that is where that bad guy goes"  Just astounding.

I know it's been a while, but I'm curious how much change there was in the Amiga source code to make it Jaguar code?  How much was 68K based would you say?  And did you have much of a problem converting the graphics files (be interesting to know what format they used) to the Jaguar graphics formats?
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ggn
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« Reply #17 on: August 13, 2009, 12:10:40 pm »

I used the TT based Jaguar dev kit - with a huge monochrome monitor; no idea what res.  Loads of screen real estate for multiple windows.  Biggest I have ever used.  In those days the ST based dev systems used a standard -was it 24 x 40?monitor. Take off 4 lines for status, title, menu and toolbar - not much room left to actually work!

I have a TT and a jag, I'd just want to ask if you still have that software devkit, I'd really like to try it out!
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Sauron
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« Reply #18 on: August 14, 2009, 10:38:49 pm »

You know - that's exactly how I felt at the time. We already had the game music - 4 channels, great samples, awesome sound.  But every time I walked past the room where the new guys were making the CD version, I felt they had really muddied and blurred the impact. Just goes to show what a good composer can do.

I have to agree with this. The in-game music turned out great, so when I first heard the CD version I was a bit disappointed.
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Trev
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« Reply #19 on: August 15, 2009, 10:00:01 am »

How does your new found older console celebrity status feel?  Grin
Pretty cool actually  Grin

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Trev
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« Reply #20 on: August 15, 2009, 10:16:33 am »


I know it's been a while, but I'm curious how much change there was in the Amiga source code to make it Jaguar code?  How much was 68K based would you say?  And did you have much of a problem converting the graphics files (be interesting to know what format they used) to the Jaguar graphics formats?

Now there's a thing.  The original Jaguar blurb - don't think this is the technical docs -  said something like "OP for the display, DSP for sound, blitter for graphics, GPU for game code, that leaves the 68000 to read the joysticks!"

How we laughed! That was before the hardware developers ran into issues. The production silicon was expected to be something like a third faster than the dev version - but it wasn't.  Of course 68000 range was well known then. Trying to write large amounts of game code in GPU assembler would have been difficult.  As it turned out it couldn't really do that anyway so we used the GPU for specific tasks like OP list creation and game-level decompression.

So for Zool-2 it was pretty simple. Use almost all the game code straight as 68000 code.  Re-write the parts for blitter use and display list management.

IIRC all the graphics were straightforward RGB16 and the sound was Amiga MODS and samples.  There was plenty of memory for everything uncompressed.
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Trev
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« Reply #21 on: August 15, 2009, 10:27:33 am »

Actually I remember now I also did the decompression routine porting.  We had some proprietary 68000 routines used for whole game level compression - one for speed , the other for space.

Clearly it was a good idea to have these run on the GPU, so I translated them. Of course I had no idea how the originals worked in detail, it was just instruction sequences.  The fast one was not too hard, but the small space one took a while. I ended up instrumenting the original and my version to write key register values to main RAM and comparing them side-by-side.  Usually when it went wrong it just exploded and stopped.  I still remember something like

mov.b d1,d2
rorc.w d2,1

deep inside caused me a headache with the different register sizes and getting that carry flag right meant going back and changing stuff from earlier.  It wasn't always as simple as 68000 instruction X gives GPU code y1,y2,y3.

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Trev
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« Reply #22 on: August 15, 2009, 10:31:13 am »

I used the TT based Jaguar dev kit - with a huge monochrome monitor; no idea what res.  Loads of screen real estate for multiple windows.  Biggest I have ever used.  In those days the ST based dev systems used a standard -was it 24 x 40?monitor. Take off 4 lines for status, title, menu and toolbar - not much room left to actually work!

I have a TT and a jag, I'd just want to ask if you still have that software devkit, I'd really like to try it out!

No. Sorry. When I left the job I left everything behind.
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Sauron
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« Reply #23 on: August 15, 2009, 10:36:32 am »

The production silicon was expected to be something like a third faster than the dev version - but it wasn't. 

Wow, interesting. I hadn't heard this before. Was Atari themselves stating this? And were they referring to clock speed or just general performance?
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Trev
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« Reply #24 on: August 15, 2009, 01:18:02 pm »

The Jag hardware was developed by a Cambridge, England company - was it Flare? I spoke to someone there a couple of times and was able to ask about some of the problems we had. The explicit mention of a faster system clock speed in the early docs was not going to happen.

I guess some of the hardware issues were just left unresolved to allow Atari to get into production before the competition (PlayStation I think) arrived the following year.  I think I have my dates right.  AFAIK the Jag was the first real multi custom/RISC processor console.

It did mark a big shift in approach to games.  Pretty much all games had been assembler code and straight to the hardware.  Like the Amiga had three books you could buy; 1-hardware, 2-kernel, 3-OS.  The Amiga guys there had never even seen 2 or 3.

Doom was new then and the experienced guys were amazed such a fast game could be written in C with just the performance critical parts in custom assembler.
Made porting very straightforward! There was a version for the Jaguar IIRC.
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Trev
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« Reply #25 on: August 15, 2009, 01:33:37 pm »

Quote
The Jag hardware was developed by a Cambridge, England company - was it Flare?

Hah! I just checked wikipedia http://en.wikipedia.org/wiki/Atari_Jaguar
It was indeed Flare. My memory is better than I thought!

But then you guys probably already knew that  Grin
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sh3-rg
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« Reply #26 on: August 15, 2009, 03:37:21 pm »

Like the Amiga had three books you could buy; 1-hardware, 2-kernel, 3-OS.  The Amiga guys there had never even seen 2 or 3.

Cheesy

Doom was new then and the experienced guys were amazed such a fast game could be written in C with just the performance critical parts in custom assembler.
Made porting very straightforward! There was a version for the Jaguar IIRC.

There was, it was pretty decent graphically.

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_ __sh3/reservoir_gods^reboot___ _
Trev
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« Reply #27 on: August 16, 2009, 07:48:36 am »

Re the porting process:
I remember having a lot of trouble with the snakes. The blitter was used (as with Amiga) to draw the body; the head and tail were sprites.  But I kept getting gaps in the body.  I think there may still have been problems with this when it was released  Sad

The snakes level was the most complex for programming and, of course, I left it to last - bad idea.

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Trev
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« Reply #28 on: August 16, 2009, 08:10:54 am »

Re testing:

After a few months of porting work the game had to go to Atari for pre-release testing. This required sending the entire game image over a 14.4 modem to Sunnyvale Smiley  About 2 hours IIRC.

I had spotted this as a major hurdle back at the start since other games had already been through this process.  I figured by the time Atari testing starts; the small chunk of game code is where most of the bugs are going to be; the huge chunk of level assets will be pretty much correct.  So, put the code at the bottom of the image and leave a pretty big gap before the assets.  That way they can be sent separately and there's room for the code to grow.

Trouble was, when testing arrived,  I had completely forgotten this - I just sent the whole lot - several nights a week for 2 or 3 weeks  Embarrassed

I did finally remember, but it was almost finished by then.
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sh3-rg
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« Reply #29 on: August 16, 2009, 03:55:50 pm »


Trouble was, when testing arrived,  I had completely forgotten this - I just sent the whole lot - several nights a week for 2 or 3 weeks  Embarrassed

I did finally remember, but it was almost finished by then.

heh, the kind of things you can look back at now & laugh, but then it's a huge D'OH!

Again, thanks for sharing Wink
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_ __sh3/reservoir_gods^reboot___ _
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