
New Pacman for Atari 2600 - shawndumas
http://atariage.com/forums/topic/229152-new-pacman-for-atari-2600/
======
sandebert
"Currently the rom is about 120 bytes free, so I'm trying to add other
things."

It's so easy to love old-school programming. (For comparison, my comment here
is 178 characters.)

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mlrtime
The same guy did Mario Bros for Atari 2600

[http://atariage.com/forums/topic/229153-a-better-mario-
bros-...](http://atariage.com/forums/topic/229153-a-better-mario-bros-for-
atari-2600/)

demo:
[https://www.youtube.com/watch?v=joYIDR4CMu0](https://www.youtube.com/watch?v=joYIDR4CMu0)

~~~
danielweber
to compare to the original:
[https://www.youtube.com/watch?v=GouYMH1K4nE](https://www.youtube.com/watch?v=GouYMH1K4nE)

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apunic
This is mindblowing.

Just check out how the original Pacman port looked on the 2600:
[https://www.youtube.com/watch?v=HL2p2ANFlQ4](https://www.youtube.com/watch?v=HL2p2ANFlQ4)

~~~
lowlevel
This is mind blowing... I'de say about 7 million people who purchased Pac Man
for the Atari 2600 were ripped off. (Myself included.)

~~~
Someone
Think of it this way: you paid for a Kickstarter project to be delivered in 40
years time, got an early proof of concept showing game play and a nice display
box, and the real thing was finished before those 40 years were up.

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flohofwoe
I always wondered how the video output was controlled without video memory. Do
you have some sort of 'current color' register which need to be set to
different values during video output, timed with nop loops?

I have coded on several 8-bit machines in 80s, but never on one without video
memory. I stumbled over this curious property of the Atari 2600 when Ed Fries
wrote 'Halo 2600' a couple of years ago (boss of the Microsoft games business
during the late 90' and early 00's).

~~~
bane
The book "Racing the Beam" has a great survey of how the 2600 worked and it's
a pretty quick and breezy book to read through.

But basically you set various display registers as the scan-line was being
drawn. Then you have the time it takes for the electron beam to move down and
across to the next scanline to do some setup and calculations and so on. And
then at the bottom of the display you have the time it takes for the scanline
to get back up to the start position for a frame to do more number crunching.

Basically instead of RAM, you read right out of ROM and fiddle with various
display registers either between lines of while lines are being drawn.

It's an old 8-bit "trick" as most people assume the registers get set and then
you do something not knowing that you can play with them while things are
going on.

~~~
Someone
That trick wasn't limited to 8-bit. The original Macintosh used a variant of
this to generate sound and to adjust the rotation speed of floppy disks. Just
past the bitmap for the screen, it had two 740-byte buffers.

It read a single byte from those buffer at the end of each horizontal scan
line, and fed it into the sound system/as a PWM signal for the motor of the
floppy drive
([http://en.m.wikipedia.org/wiki/Macintosh_128K/512K_technical...](http://en.m.wikipedia.org/wiki/Macintosh_128K/512K_technical_details#Sound).
I think the section on the floppy drive is incorrect; the original Mac didn't
have a IWM; it was all done in software)

If you wanted to generate continuous, non-repetitive sound, you had to fill
the sound buffer with new values at the end of each vertical blank interrupt.

Quite a bit easier than on the 2600, as the update frequency is only 60 Hz and
the CPU a lot faster, but the same principle, and still quite a challenge at
the time, if you wanted to do something in the screen at the same time.

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acomjean
Wonder if how close they managed to make the ghosts move like the arcade
version. Someone reversed engineered how the ghosts chase you, each one chases
using a different algorithm which ends up making the game really interesting
to play.

[http://home.comcast.net/~jpittman2/pacman/pacmandossier.html...](http://home.comcast.net/~jpittman2/pacman/pacmandossier.html#Chapter_4)

~~~
bitwize
Actually all four of the ghosts have different chase algorithms: Blinky
aggressively chases you, Pinky and Inky try to get in front of you (setting
you up for a pincer attack with Blinky), and Clyde chases you until he gets
within a certain distance, then makes a break for the lower left. (Hence why
he's considered the stupid one.)

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certainly_not
The embedded video is not showing up for me. I believe this is the one though:
[https://www.youtube.com/watch?v=clddb79LQcM](https://www.youtube.com/watch?v=clddb79LQcM)

~~~
danielweber
I think the embedded one is
[https://www.youtube.com/watch?v=n4tFhEQFs7I](https://www.youtube.com/watch?v=n4tFhEQFs7I)
but your link is of better quality.

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JoeAcchino
I didn't know that there are homebrew games for Atari 2600.

They also assembled a tutorial for beginners:
[http://atariage.com/forums/topic/33233-sorted-table-of-
conte...](http://atariage.com/forums/topic/33233-sorted-table-of-contents/)

~~~
fit2rule
Oh, there are new homebrew games being made for a lot of the major 8-bit
machines, still today. Myself, I've been enjoying the revival immensely,
especially since the 8-bit machine of my youth rarely got much attention at
all from the major industry developers (Oric-1/Atmos), yet today - in the 21st
Century - its getting a regular stream of releases from the die-hard holdouts
.. and some of them are absolutely amazing products which would have been huge
hits back in the day.

(See
[http://www.oric.org/index.php?page=software&fille=top150game...](http://www.oric.org/index.php?page=software&fille=top150gamesoverall))

We got Space:1999, 1337 (Elite clone), SchoolDaze, Impossible Mission,
Oricium, 4K Kong .. a lot of really awesome titles .. in the last few years.
Also, new techniques have been discovered and continually refined by the core
die-hards, meaning we're seeing things on the platform that we in the 80's
could only ever have dreamed of seeing .. new color modes, new ways of
handling animation, etc. It really is astounding to return to these platforms,
30 years later, and see new titles being pushed out by the ever-eager hackers
who are keeping the platforms alive. Heck, we even got new hardware for the
Oric-1/Atmos platform in the form of a dedicated disk emulation system, whose
microcontroller alone, itself, is more powerful than the Oric ever was, but
which nevertheless is being pressed into the disk-emulating duties that makes
the Oric-1, at last complete. ;)

So if you've got an old 8-bit machine in your closet, get it out, wire it up,
dust if off, and get out there on the 'net to find the elite groups keeping
these systems alive. And remember: old computers never die - their users do!

~~~
RodgerTheGreat
The surplus of resources on modern PCs makes it possible to make development
tools which would have been positively indulgent by the standards of their
day- sophisticated debuggers, the ability to pause, freeze and replay
execution while inspecting every byte of memory at will, fancy languages that
remove tedium, etc.

For my part I made a pretty nice high-level assembler and IDE for the
venerable Chip8: [http://octo-ide.com](http://octo-ide.com)

~~~
fit2rule
Wow, looks really useful! Its amazing to think how far we've come, and yet
return to these limited machines and push them as far as possible. Something
we have to keep future generations of developers enlightened about, I think.

