New interpretation of Pitfall! for PAL Vic + 16K

[Victragic]

Hi all,

here's a game I've been working on for a while - I loved the original Pitfall! for Atari 2600, and wondered what it would be like to try to create a version for the Vic.



The original was written for a 4k cartridge - my 20k version is quite bloated in comparison. The Atari had some hardware advantages over the Vic, and the game was clearly written with the 2600 hardware in mind.

I've no idea whether this works on a real Vic or not, sorry - I have no way of transferring files to my VIC at the moment.

For anyone who is interested, download at :

https://docs.google.com/file/d/0BypQg4Q ... sp=sharing

Edit 11/9/13:
Thanks to those who offered to host, I think the above link will be a more permanent solution and allow for better document control.


Known bugs :

1. There's a bug that causes the rasters to be set up incorrectly about one in thirty times, not sure why this is happening. Load again if this occurs -- <<EDIT: think this is fixed with Tokra's advice.>>

2. Minor colour glitches. They have to stay as is for the time being.. <<EDIT: fixed the main problem, with the vine>>

3. Sorry, only PAL + 16K. NTSC version not planned.

4. PAL slowdown - unavoidable, so I've added 4 minutes extra to attempt to finish the game.

5. Others bugs and limitations but.. I need to put this project down now <<EDIT: Ha! >>

Hope you enjoy!

-Glen aka Victragic

[pallas]

Very nice! Just played for some minutes on vice, but will do on the real vic asap!

[Kweepa]

Looks amazing!
Did you create a VICE palette specially for the game? Those tree trunks look very brown.

Good to know you haven't abandoned the friendly computer!

[orion70]

Incredibly incredible!!! Congratulations on this. I've always liked Pitfall! soooo much, and this version is VERY good. Thank you so much. We've been tinkering around with the idea of that Wizard of Wor bootleg, and now you come with a VIC version of Pitfall! - and it's right there on my PC

Will try this on the real machine asap.

Did you create a VICE palette specially for the game? Those tree trunks look very brown.

Try THIS palette instead (I use it in VICE 2.3, follow instructions HERE if you can't load it directly from the VICE Video Menu - remember to reload VICE afterwards).

Pitfall! Can't believe it!

[Ghislain]

I'm going to try this when I get the chance.

I'm also a big fan of VIC-20 interpretations of those classic games. Finally, that clunky BASIC version of VICFALL has been surpassed

[Boray]

I just tried it on a real Vic. I don't think I've played Pitfall before, but this is amazing! What a professional feel to this! Just one thing... I tried to load it about 5 times with no success before trying to load it ,8,1 instead of just ,8. So now I just loaded it ,8,1 and re-saved it ,8.

[Mike]

I tried to load it about 5 times with no success [...]

That happens because of a wrong load address in the *.prg file.

Saved BASIC programs (also ML programs with a BASIC stub) are supposed to start at $1201 with a +8K (or bigger) RAM expansion. The byte containing 0 at $1200 is not saved along with the program.

For more details please refer to my reply to Witzo's OP in the thread 'How to compile assembly with a basic start line?'.

While it is an easy issue to resolve, it just again shows that the autostart behaviour of VICE - loading files with ',8,1' and then RUNning them - is a design failure. Either I load a file ',8' and then RUN it, or I load it ',8,1' and then SYS to it.

(proceeding to happily try out PITFALL for the VIC-20 From what I could gather from the screenshots already, you're using in-line splits of the background colour to draw the tree trunks and pits and dynamic updates of the colour RAM positions used by the player character - this puts your implementation in the same league as Dragonfire by Imagic! Please add this release to the Announcement thread for 2013. )

[e5frog]

Tried it in WinVICE, screens doesn't match up...

I start in a screen with no real dangers, just a ladder down and a still log. I go to the left, there's three holes, middle one with a ladder, two rolling logs. If I jump down a hole and go to the right, I get to another screen, now there's a rope and a black pit shrinking and growing, something you have to walk two screens to the left to reach.

If I go down and then left I don't see the crocodiles in the water. The water is now shrink and grow type instead...

So it seems the half screens is out of order.

[tokra]

Pitfall! [...] for the Vic.

Holy smokes! This is brilliant! As Mike said using dynamic updates of $900f for trees, ladders and especially the opening and closing pits is ingenious! And then the dynamic char-colors top it off. Congrats!

Known bugs :

1. There's a bug that causes the rasters to be set up incorrectly about one in thirty times, not sure why this is happening. Load again if this occurs

It may be possible that the check for the first raster actually happens WHILE that rasterline is being displayed. Chances should be 1 in 131, but I noticed this behaviour in developing my graphic modes as well. Since then to be safe I do it like this:

Code: Select all

        ldy        #$01        ; make sure next command really STARTS at line #$09 and not SOMEWHERE in it
raster0 cpy        $9004
        bne        raster0
        ldy        #$03        ; wait for this raster line (times 2)
raster1 cpy        $9004
        bne        raster1     ; at this stage, the inaccuracy is 7 clock cycles

Note: you must do the second check at least 2 values later (like here #$01 then #$03), since you may be at the very end of #$01 when you check and this could again lead to incorrect timing.

3. Sorry, only PAL + 16K. NTSC version not planned.

I've just recently investigated how Dragonfire does its NTSC-compatibility. They use code like this for every rasterline they fiddle with:

Code: Select all

.C:b6ab  24 DF       BIT $DF
.C:b6ad  10 02       BPL $B6B1
.C:b6af  48          PHA
.C:b6b0  68          PLA
.C:b6b1  A2 04       LDX #$04

$df holds the information whether the machine is NTSC or PAL. Depending the branch is taken or not (2 or 3 cycles), another 7 cycles are wasted (PHA, PLA) before continuing to the next code segment. So PAL takes 2+7=9 cycles (no branch+wait), while NTSC takes just 3 cycles (branch) for a difference of 6 cycles which is exactly the NTSC to PAL difference (65 cycles per line for NTSC, 71 cycles per line for PAL).

I need to put this project down now

Well, don't expect to drop such a bombshell of a 98% finished game without starting a vivid discussion. Deep down you know you want to polish the final 2% out of it or you would not have posted it

Again, thanks for such a fine release!

e5frog: I believe in the original Pitfall the screens would jump differently as well if you took the underground-route. I remember reading somewhere you skip up to 4 screens this way. Maybe this is what you are seeing?

[orion70]

e5frog: tokra is right. You can skip levels moving underground. See this excellent map. I wonder if this coversion follows its topography

[e5frog]

Aha, guess I played it too little.

I missed the music but the graphics looks wonderful.

[Victragic]

Thanks for the comments everyone..

Dragonfire was the inspiration for doing this in the first place - I had a few minutes wondering how they did that while playing that on the Megacart. It started me wondering how I might do something similar on the Vic.

An identical NTSC version isn't really possible - *every* byte is used in a raster line, with no branching. To write this for NTSC would mean dropping the dynamic colouring for the main character.

Saved BASIC programs (also ML programs with a BASIC stub) are supposed to start at $1201 with a +8K (or bigger) RAM expansion. The byte containing 0 at $1200 is not saved along with the program.

Had no idea, and again, really wish I had the real hardware to develop this on.

It may be possible that the check for the first raster actually happens WHILE that rasterline is being displayed.

I had suspected this might be the case, will implement as you suggest.

I believe in the original Pitfall the screens would jump differently as well if you took the underground-route. I remember reading somewhere you skip up to 4 screens this way. Maybe this is what you are seeing?

In this version, moving off-screen shifts you three screens across.. now I'm not sure if that is the right number!

Finally, that clunky BASIC version of VICFALL has been surpassed Smile

Hey, I like that version - it's genuine retro, unlike my fabrication.

[Victragic]

Did you create a VICE palette specially for the game?

No, but I knew that the VICE palette I've been using is well out - the orange looks brown, and various other colours have the wrong luminance.. will try that suggested palette.

..would love to see a shot of it running on a real Vic.

Deep down you know you want to polish the final 2% out of it or you would not have posted it Wink

lol - actually I'm just time pressed now, so I set myself this deadline. (Well, the deadline was last week, like all projects it went a little over every line I drew in the sand..)

[/quote]

[tokra]

I knew that the VICE palette I've been using is well out - the orange looks brown, and various other colours have the wrong luminance.. will try that suggested palette.

You may also want to try this one:

http://www.tokra.de/vic/mike.vpl

See this thread
This palette was done by Mike from my VIC when after he S-Video-modded it.

In this version, moving off-screen shifts you three screens across.. now I'm not sure if that is the right number!

According to the map which orion70 linked 3 screens sound about right.

After further trying this game, I just love it how the scorpion advances to you and stops just right at the char-boundary to avoid color-clash

Any particular reason why you changed the music for the vines and player death? The conversion is so perfect I subconsciously was EXPECTING the original Atari VCS-music as well?

[English Invader]

Beats the crap out of the C64 version of Pitfall!