Author Topic: R-Type  (Read 71910 times)

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Keith A Goodyer

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Hi Guys (and Mark) Sorry haven't been back in a while - have had some  somewhat distracting personal issues over the past couple of months -  Mark I'm still up for it. 
   
    OK, I developed R-TYPE using the fantastic PDS system written by Foo   Katan. For those who have never heard of PDS, it was probably the   worlds first IDE - Editor, Cross Assembler, Linker and Debugger all in   one.  It run on the x86 architecture under DOS, and had a hardware   component that allowed you to 'Download' the compiled code directly onto   the target hardware. It eventually supported development for Z80, 6502,   and 68K.  It was probably the mainstay of all Video game programming in   the late 80's.
   
    I was very fortunate to be given Bob Papes EXECELENT source code for the   speccy version. I have never met Bob but have spoken to him on the   phone.  I have the highest regard for him!  Although the code wasn't   that well documented, many of his labels were somewhat self descriptive.
   
    Given the extream time limits i was given to the port this is basic   strategy that I took to do the port...  (I hope i remember all this   correctly)
   
  The spectrum had its ROM in the lower 16K, and the 48K of RAM above  it.  So I configured the Amstrad to locate the MODE 1 screen in the  lower 16K, and loaded the spectrum version in the top 48K (As it would  be located on a spectrum - and ran it).  I then went through the code  line by line, modifying anything that 'plotted' pixels on the screen to  something that would plot the equivalent pixels on on Arnolds screen.
   
    As the spectrum screen is 'Attribute Based' I continued to used all of   Bobs 'Colour' code, and the whole 768 bytes of the spectrum colour   attribute screen is running on the Amstrad version.  When ever there was   a 'Byte' write to the spectrum screen, I would use a look up table to   indexed by the byte and the value of the corresponding spectrum colour   attribute to extract the two bytes required to produce the correct   pixels on the CPC screen. Then all I had to do was port the control   (Sinclair/Kempston) to CPC stuck, and the Sound and the job was done.  A   few days with DJL to add the 'Protection' and the job was done.
   
    Now the sad news...  about 5 years ago, I had a massive leak in my roof,   and all my records (including the source code) was destroyed.  :(
   
   
    Now some Trivia:  At the time I had a 464, 664 and a 6128 - I took the   final masters down to Activision, and it would not run on their 6128.    It tuned out that at some point in time, Amstrad had made a small   revision to the design that meant that a the interrupt would fire just   before a frame fly back pulse, where on previous versions it would occur   just after. The net effect was that when my code was waiting for the   frame fly back pulse to occur, the interrupt would trigger just before   it, go off do some processing, and by the time it had finished the   processing and returend to the main code loop, had missed the pulse -   and locked up.

Noticing the name of this forum - I only have one thing to say...  We all have to eat!  LOL

As for the industry in the early days... It was fantastic!  The egos, and personalities were out of this world. There were some VERY clever guys, and there were some VERY slimey men in suites that knew how to abuse the geeks.  One of the greatest things to happen in those early days were Richard and David Darling, people dont remember that Codemasters was founded by two school boys.  I do remember a great night out in Lemington Spa with those two, and a missing traffic cone or two.

Keith


Offline ukmarkh

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Fantastic stuff... look forward to doing the interview soon, will be in touch shortly.

Offline MacDeath

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Quote
VERY slimey men in suites that knew how to abuse the geeks.
This explains all.

Thank you for those story.

The sad part is perhaps that you were'nt given a Graphist to get a real Amstrad Mode1 recode of those....
« Last Edit: 23:06, 19 April 10 by MacDeath »

Offline fano

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Thanks a lot for this  ;D

 
    Now the sad news...  about 5 years ago, I had a massive leak in my roof,   and all my records (including the source code) was destroyed.  :(
  :'(
"NOP" is the perfect program : short , fast and (known) bug free

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Offline MacDeath

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Work in progress... ;)

Offline Gryzor

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I really love these mock-ups...

Offline MacDeath

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Those mock ups have the exact tile seting thanks to Fano Dev kit...

But it's quite long to work because I must do eack tile separately (with Graphx2), and i'm doing every levels and sprite...

Some part are well started, other not.


At first I simply recolour, but after it is donne I rework the pixels a bit, and try to had a 3colour dithering.

So instead of the 1 bit dithering, it will be Black-Colour-White...this is the longer par IMO.

I also have Arcade's levels mock, it fun to compare with the Speccy/amstrad graphics.
In fact I think the original Graphist had access to the Arcade Datas, because it often match to the pixel, just some elements were reduced or using only bits of the original graphic.

Aso a lot less tile because of the Speccy 48K limitation, and a reduced screen because of Speccy's shitty resolution.

BTW the speccy version was incredibly accurate, so is the CPc version, because it's the same.


Offline TFM

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Work in progress... ;)

Hey MacDeath!
 
That's awesome. Now let me ask you a question. Do you have that graphics also as CPC screens? Can you send me them as 17 KB screens? I would like to try something with it, you would be the first who get's the result ;-)
 
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Offline MacDeath

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@ TFM/FS : What CPC screen ?

In fact I have a tile set, and Fano's devKit enable to place the tiles in one big picture, recreating the Levels...on a PC.

Also as it is a WIP and a project with Fano, I wouldn't like to give you all his stuff.

Ask him before.


But I may craft you a mockup to convert with convimgcpc or whatever you like...



On another topic :
Bingo !!!!

I found out that the Speccy/CPC version of R-Typer is somewhat ported from the Atari ST version (Graphiocally), I managed to find some pictures of the Atari versionl and it seems to match well the Speccy version (concerning the tiles mostly).

Also the 16 colours Atari ST version is helpfull for me to do some ditherings...


I put you 2 Atari ST pics, you may compare with the 2nd level : the background tiles are exactly the same, also the Atari ST (as a fully softwared machine) doesn't have any background...but a starfield...

So basically the r-Type port was managed exactly like PacMania...(and vice-versa).

Amiga and C64 got theyr own version, and Atari-Speccy-Amstrad were developped in the same batch, with the CPC version simply a emulator based Speccy port.

Where the men in suit did it wrong ?
Well, they asked Goodyer to do the port from speccy when it was completly finished...
A more proper way would have been to ask him to work with the speccy team at the same time and with each other (perhaps not possible due to geographic distance) and the Graphist would then do both version instead of only Speccy...

But hey, if men in suit were geeks friendly, would would knew it... :D
« Last Edit: 19:44, 21 April 10 by MacDeath »

Offline Devilmarkus

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Would look cool in MODE 0... Do you think this would be possible?

CPC+ example: (perhaps in final version: real sprites)
« Last Edit: 19:58, 21 April 10 by Devilmarkus »
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