My 2600 -> 8bit Game Port

[BIGHMW]

3 hours ago, MrFish said:

BTW... if you're concerned about the lack of attention you're getting... a lot of people don't frequent the programming section here -- as it's more for programming technical questions and discussions. Posting on the main for will get more responses/interest.

 

He (and his port) will get the attention they deserve (and then some!) when I review it on the 8-Bit Edition of The Atari Report, YouTube's fastest-growing homegrown amateur classic gaming review channel!!! 92 subscribers and counting (I only need 8 for that magic 100 mark and then I can get that custom URL, and I already have the name picked out for the URL too!!!)

 

https://www.youtube.com/channel/UCgW22q4hD1AhsdRkno-SLFw

Edited November 21, 2021 by BIGHMW

[BIGHMW]

4 hours ago, MrFish said:

BTW... if you're concerned about the lack of attention you're getting... a lot of people don't frequent the programming section here -- as it's more for programming technical questions and discussions. Posting on the main forum will get more responses/interest.

I think @ZeroPage Homebrew is starting to get this port (and @glurk) the proper attention they rightfully deserve, check out the latest posts on this thread!!!

 

 

It's in a forum that gets plenty of attention and maybe this will kickstart this thing to a newer and higher gear, it just takes one of us!!!

[BIGHMW]

I gave this game its own thread in the main 8-bit forums, help a bro out!!!

 

 

[Thelen]

On 11/20/2021 at 11:41 PM, glurk said:

It's nearly finished, so at least for now I want to finish the geese, get it bug-free and call it done.  I'm still thinking on some programming issues.  This is the first and only 2600 port I've ever done, so it's been a learning experience.  In hindsight, I probably should have chosen a more popular game...

 

 

It's indeed as MrFish says, most A8 users don't look here since there are less things going on here.

I think you've done a great job with this conversion so far! Funny fact is that I never played the 2600 version a lot because I didn't understand what was really the point of the game. Now I've tested yours and finally know what to do, it's a great game! I hope you have enough motivation to finish the game!

[Thelen]

And, may I ask if you've done the disassembly 2600 code yourself, or was there already a disassembled source with comments or something like that? I've never done a port, and I'm curious how the 2600 source looks... ?

Edited November 22, 2021 by Thelen

[glurk]

When I started on it, I just ripped the graphics from the 2600 ROM and created the display list / graphics from those.  Matching it up with Altirra and Stella emulators.  I planned to do the game code from scratch, but I then found Dennis Debro's commented source, (kudos to him) and figured out that I could use the original game code.  It's a good thing, and it allowed me to get it done MUCH faster!!

 

I don't think I'll be releasing my source code, because it wouldn't win any coding style awards, LOL.  It's quite a mess...  Of course, what matters is that the end result game is solid, and I believe it is.  I mean, I like sausage, but I don't want to see how they make it, hahaha.... 

[Thelen]

Oh, I'm sorry, I didn't mean your sourcecode- but the commented 2600 sourcecode ?

[glurk]

I found it here on the board somewhere.  But look here --> http://www.bjars.com/disassemblies.html

 

[Thelen]

5 hours ago, glurk said:

I found it here on the board somewhere.  But look here --> http://www.bjars.com/disassemblies.html

 

Cool, Thanks!

[glurk]

Another question - for anyone.  When I did this Barnstorming port, I pretty much chose all the color values "by hand."  Because the 2600 palette is not the same as the GTIA one.  But just for reference, is there (somewhere) a conversion chart??  2600 Colors <-> GTIA Colors?

 

I have one to convert GTIA NTSC to PAL, it's great.  But no help with 2600...

[sanny]

Probably you need two 2600<-->GTIA carts, one PAL, one NTSC.

[glurk]

I think my approach would be NTSC 2600 --> NTSC 8-Bit, and then use my existing one for NTSC 8-Bit --> PAL 8-Bit

 

The 2600 and GTIA palettes are real close, but just not quite right.  And it bugs me to death, LOL.  I have to stop programming, open two browser windows, look up some online color charts, and compare.  It's a huge time waste, one conversion chart would be SO MUCH EASIER.

 

[glurk]

I've got the color thing sorted.  More or less (to get close) take the 2600 values, and add 2, LOL.  Not exact, but it gets close enough to hand-tune.

 

But NOW I have a different problem.  I'm working on ANOTHER port.  A much more popular game, which I don't want to name yet.  I don't want anyone to get excited about it, because I don't yet know if I can pull it off...

 

Thing is, I'm not a graphic artist.  And my vision sucks.  So -- what I need help with...  I have 3 8-bit wide "player" objects, and I need to expand them to 16-bit wide.  Two bytes in width each.  And I've given up trying to do it by hand.   Is there some tool to do this?  Can I do it mathematically?

 

Maybe there's an easy way I'm missing.  Maybe I'm just dumb...  I guess a one-line example might do...

 

.byte $85 = 'X....X.X'  into .byte $C0,$33 = 'XX......','..XX..XX'

Edited December 1, 2021 by glurk
correction

[Wrathchild]

If you can spare 2 pages of RAM/ROM then use lookup tables, e.g.

TAY
LDX HiNibble,Y
LDA LoNibble,Y

This can be done with a Macro (i.e. mathematically)

HiNibble: 
    .rept 256, #
    .byte [#&$80]+[[#&$80]/2]+[[#&$40]/2]+[[#&$40]/4]+[[#&$20]/4]+[[#&$20]/8]+[[#&$10]/8]+[[#&$10]/16]
    .endr
LoNibble: 
    .rept 256, #
    .byte [[#&8]*16]+[[#&8]*8]+[[#&4]*8]+[[#&4]*4]+[[#&2]*4]+[[#&2]*2]+[[#&1]*2]+[#&1]
    .endr

Though the expansion of that is:

HiNibble: 
     .byte $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00
     .byte $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03
     .byte $0C, $0C, $0C, $0C, $0C, $0C, $0C, $0C, $0C, $0C, $0C, $0C, $0C, $0C, $0C, $0C
     .byte $0F, $0F, $0F, $0F, $0F, $0F, $0F, $0F, $0F, $0F, $0F, $0F, $0F, $0F, $0F, $0F
     .byte $30, $30, $30, $30, $30, $30, $30, $30, $30, $30, $30, $30, $30, $30, $30, $30
     .byte $33, $33, $33, $33, $33, $33, $33, $33, $33, $33, $33, $33, $33, $33, $33, $33
     .byte $3C, $3C, $3C, $3C, $3C, $3C, $3C, $3C, $3C, $3C, $3C, $3C, $3C, $3C, $3C, $3C
     .byte $3F, $3F, $3F, $3F, $3F, $3F, $3F, $3F, $3F, $3F, $3F, $3F, $3F, $3F, $3F, $3F
     .byte $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0
     .byte $C3, $C3, $C3, $C3, $C3, $C3, $C3, $C3, $C3, $C3, $C3, $C3, $C3, $C3, $C3, $C3
     .byte $CC, $CC, $CC, $CC, $CC, $CC, $CC, $CC, $CC, $CC, $CC, $CC, $CC, $CC, $CC, $CC
     .byte $CF, $CF, $CF, $CF, $CF, $CF, $CF, $CF, $CF, $CF, $CF, $CF, $CF, $CF, $CF, $CF
     .byte $F0, $F0, $F0, $F0, $F0, $F0, $F0, $F0, $F0, $F0, $F0, $F0, $F0, $F0, $F0, $F0
     .byte $F3, $F3, $F3, $F3, $F3, $F3, $F3, $F3, $F3, $F3, $F3, $F3, $F3, $F3, $F3, $F3
     .byte $FC, $FC, $FC, $FC, $FC, $FC, $FC, $FC, $FC, $FC, $FC, $FC, $FC, $FC, $FC, $FC
     .byte $FF, $FF, $FF, $FF, $FF, $FF, $FF, $FF, $FF, $FF, $FF, $FF, $FF, $FF, $FF, $FF
LoNibble: 
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF
     .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF

This demonstrates a high degree of repetition though, so at the sacrifice of cycles to obtain the values, this can also be done:

DblNibble: 
    .byte $00, $03, $0C, $0F, $30, $33, $3C, $3F, $C0, $C3, $CC, $CF, $F0, $F3, $FC, $FF

    PHA
:4  LSR ; A
    TAY
    LDX DblNibble,Y 
    PLA
    AND #$F
    TAY
    LDA DblNibble,Y

    
    

 

Edited December 1, 2021 by Wrathchild

[glurk]

Fantastic, thank you!

 

[+ZeroPage Homebrew]

ZeroPage Homebrew is playing Barnstorming on tomorrow's stream LIVE on Twitch, hope you can join us!

 

Tue Dec 7 @ 6PM PT | 9PM ET | 2AM GMT+2Day

WATCH: https://www.twitch.tv/zeropagehomebrew/

Games:

• Gacek (2021 | A8) by Janusz Chabowski @shanti77
• Castle Defender (2021 | A8) by Martin Simeček @matosimi (Code & Design), Piotr Radecki (Title Screen), Michal Radecki (Music)
• Barnstorming (2021 | A8) by glurk @glurk
• Pang (2016 | A8) by Tomasz Biela @tebe /Madteam, Kamil Walaszek (Vidol) & Adam Pwroznik (Ooz / Agenda) & Maciej Hauke (Rocky / Madteam) (Graphics), Michal Radecki (String / Agenda) (Music)

 (WATCH AT 1080P60 FOR BEST QUALITY)

 

 

 

 

[bfollett]

Just a minor observation:  Looking at the original game and box art.  There is a white fence across the bottom of the screen.  Your fence is tan and appears offset by a pixel in the middle, so it looks more like railroad tracks than a fence.  Not sure if it was on purpose but I thought I'd point it out in case it wasn't intentional.

[glurk]

3 hours ago, bfollett said:

Just a minor observation:  Looking at the original game and box art.  There is a white fence across the bottom of the screen.  Your fence is tan and appears offset by a pixel in the middle, so it looks more like railroad tracks than a fence.  Not sure if it was on purpose but I thought I'd point it out in case it wasn't intentional.

It's intentional.  It's one of my little graphics touches, it's supposed to look like a split-rail type fence, with added perspective.  I think it looks good.  Can't please everyone, LOL!