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Chuckie Egg

Posted: Tue Dec 28, 2010 7:41 pm
by PitfallJones
New Game!
ChuckieEgg.png
ChuckieEgg.png (4.81 KiB) Viewed 5829 times

Re: Chuckie Egg

Posted: Wed Dec 29, 2010 3:40 pm
by paul
Man, you work fast! It looks like a great port. Sadly I failed on level 3 my first two tries, but I did get to see the elevators (very cool). How many levels are there?

Great job, Pitfall!

Re: Chuckie Egg

Posted: Wed Dec 29, 2010 8:29 pm
by uze6666
Great game! I never got to play it back then but I know it was a big hit. And this is indeed a very good port. One small thing that could make it even better: add a little leniency when taking the ladders. That is, allow to climb if the player is not exactly aligned on the ladder (i.e: one or two pixels off each side). I've done that for Lode Runner and it speeds up things significantly.

In any case, that's awesome work in such a small timeframe!

EDIT: I've added a Wiki entry for the game.
EDIT2: Been playing more...and more...and more...classic game play!! I noticed we can catch ladders mid air, so my previous comment about leniency is not that much relevant anymore. :D

-Uze

ps: Do you plan to release the sources?

Re: Chuckie Egg

Posted: Thu Dec 30, 2010 11:46 pm
by PitfallJones
Hi,

Thanks for the feedback, chaps - great to see it added to the Wiki!

There's 8 levels in the game then the baddies change their patterns.

Here's a link to the ultimate Chuckie Egg fansite with loads of info:

http://www.bagshot-row.org/chuckie-egg/

I'm afraid I'm not that fast -- Mike Elson wrote a PC remake of the 8-bit BBC Micro version which I used as the core of this version and then I used Donkey Kong Uzebox as the shell.
I was really confused at first as to why sprites wouldn't appear (makefile options) and the mechanism for rom (flash) access.(pgm_read_...)

I found ram usage a real problem and had to remove multiple players and the hi-score to get it to fit.

Also the sprite limit cut down the bad guys on screen.

I've noticed a random crash where the screen freaks out - which is strange as my pc simulation of the program appears to have no memory leaks - maybe it's a too many sprites thing.
Also turning on the noise channel makes it freak out as well.

Still - it's great fun to get something running.

I'll post the source in a couple of days once I've cleaned it up.

- PJ

P.S. I'd be really interested if somebody could set up a 256x192 mode or 160x224 (which is what Chuckie actually uses).
An option to make the sides blanked or stretched to fill the whole screen would be cool as well. (you could have 1:1 pixel aspect game then with a blank border)
There's a whole bunch of 8bit games that could be converted more easily to run on the Uzebox then (and save some memory)!
I have another in mind already ....

Re: Chuckie Egg

Posted: Fri Dec 31, 2010 4:07 am
by paul
Thanks for the backstory, I enjoyed it.

When you talk about removing hi scores, was it the EepromBlockStruct that tipped you over? If so, you can see in Donkey Kong I just re-used the enemies' memory because they're all dead when it's needed :lol:
Incidentally, I had to do the same for the elevators.

Also, if you can remove one of the screen rows (you don't seem to be using the bottom row) you can claw some vram back that may help. I did this in DK and it removed any slowdown (although I never released that version for whatever reason). I'm looking forward to your future games!

Re: Chuckie Egg

Posted: Wed Jan 05, 2011 2:10 am
by uze6666
Crashes are usually created by two things: Having kept not enough free RAM and to many sprites at once which takes more time to process than the free cycles in VSYNC. Both will result is stack overflow and crash the game. Always insure you keep at least 5% of free RAM from the stack, a bit more if you use a lot of local variables. To test if free cycles is the issue, disable all sound channels and see if the crashes stops.
P.S. I'd be really interested if somebody could set up a 256x192 mode or 160x224 (which is what Chuckie actually uses).
An option to make the sides blanked or stretched to fill the whole screen would be cool as well. (you could have 1:1 pixel aspect game then with a blank border)
There's a whole bunch of 8bit games that could be converted more easily to run on the Uzebox then (and save some memory)!
I have another in mind already ....
240 pixels wide is the maximum we can get if you want sprites, so a 256x192 would not be possible. However, 160x224 is quite easy. You could recover RAM for about 4 more ramtiles. If no horizontal scrolling is required, I think it could be made to recover the CPU in the blank sides for the main program. Would you need scrolling for this mode?

-Uze

Re: Chuckie Egg

Posted: Wed Jan 05, 2011 5:09 pm
by PitfallJones
Thanks for the tips about crashes - I'll give it a go.
No - no scrolling is need for the 160 mode.
A method of setting up any X x Y resolution mode3 like screen would be useful - a good way to save a little ram.
I would say the lack of ram is the Uzes biggest limitation - ram always gives flexibility -- which I think is why a C64 or Atari800 is able to do much more varied games than lets say a Atari7800. As those platforms had palletted graphics as well their effective room for sprites is 2x or 4x as large!
A pity about the 256x192 mode - I was thinking about all those great zx-spectrum games!
- PJ

Re: Chuckie Egg

Posted: Thu Jan 06, 2011 3:49 am
by uze6666
Well, for mode 3 you can actually control the vertical display resolution and allocated VRAM using the SCREEN_TILES_V and VRAM_TILES_V compile switches.

Yeah I know RAM is very limited and sometimes it can be tricky to do something with it. More RAM would allow more ram tiles, but even then, we are limited in the number of cycles required to pre-render them during VSYNC. If the Uzebox had the C64 and Atari's dedicated video and sprite hardware, we could indeed get more creative!

256x192 is perhaps not critical to make good ports. Just look at Paul McPhee's Pac-Man and Donkey Kong. He resized a lot of thing to fit with the limitations. In the end it didn't matter much since the game play was intact and that's what counted the most (IMHO of course :) ).

-Uze

Re: Chuckie Egg

Posted: Fri Sep 09, 2011 6:51 pm
by hpglow
I just got done playing, good game. I never played the original so I can't say how close it was. The only glitch I noticed is that I got stuck and un-able to move sometimes when trying to get off a ladder, and jumping off didn't work either. Other than that the game played fine.