[Video Chess level 7]

Ok. I now have enough data to write a very informative article on Video Chess and some of the techniques that were used in its code.

 

However, I disassembled it because I wanted to know about the level 6 and 7 bug. I've a very good suspect based on the small stack space available, but I need to find a way to prove it.

 

Also some code triggers a pattern in my mind, and I need to compare against an older chess program.

[Video Chess level 7]

18 hours ago, davyK said:

I'm guessing each node in the decision tree holds the evaluation score for both players and the last move, but how does it evaluate the score without encoding the entire board at each node? Unless it stores the difference between each board state at each node too and work the new eval score from that? Hair raising stuff.

Would be really interesting to see a commented listing. (I presume the games uses a decision tree with an evaluation function since that was the prime way to day these game back in the 70s/80s).

So far there is nothing like trees and nodes.

 

This is what I've got so far (still work to do, because I'm searching how it validates legal moves, and where it returns to video chores).

 

It is based on a simulated stack using 4-bit values preserved in the same bytes as the chessboard (lower 4 bits for board).

 

It starts analyzing the board from the bottom-right corner, and once it finds an own piece, it saves the current state in this simulated stack, it does the movement, and it starts another board analysis with the opposite side (it can deepen even more), once this is finished, it reverts the movement using the information on the stack, and it continues where it was.

 

[Video Chess level 7]

I'm curious enough so I've started disassembling and analyzing the code of Video Chess.

 

Edit: So far I found the Reset/Select buttons code operation and how the chessboard is setup so now I know how the pieces are represented and the board addresses.

 

Edit 2: Now I know where it handles the joystick movement and button, along with the chessboard editing feature. I found the movement generator, the code to restore the board after a movement, and the code to change the background color as the Atari "thinks". Now I need to find the code that saves the board state before a movement.

[Failed Crystal in Heavy Sixer, Anyone?]

I never have found a failed crystal.

 

I would suspect the TIA is having an "almost" short-circuit.

[Princess Quest for Intellivision ROM now free]

3 hours ago, SpiceWare said:

Reviewed by the Video Game Critic.

 

VGC Forum discussion here:

 

 

Thanks! It is a nice review 😃

[Adventure Game, or: Initial Memory Concerns]

It depends on how much dialogue you expect to have.

 

My suggestion would be to code the first few screens, and then having a semi-playable game you can estimate/calculate the size of your dialogs.

 

For a first game it is entirely possible everything can fit without compression.

[Maybe another Chess game?]

Mr. Chess review by Gray Defender

 

 

 

[Ignore this thread.]

I saw the title... but... resistance is futile 😂

 

[Maybe another Chess game?]

I've wrote a small article about the development of Mr. Chess for Intellivision. It includes the source code of the earliest version (though not a full game) Enjoy it!

 

https://nanochess.org/mr_chess.html

[Intellivision Booblet]

It is a special type of dress for women.

[HEEELP! Ladder bug in scrolling platformer]

1 minute ago, DZ-Jay said:

 

So, to recap, the only problem was when copying the position to the SPRITE command for display; the rest of the functions and variables were correct.  Right?

 

(That is apart from the problem of not truncating the fraction when the sprite is "snapped" to the ladder column.)

 

Apparently yes. The mystery was why the red block wasn't shown the way it was supposed to.

 

[HEEELP! Ladder bug in scrolling platformer]

Hi @Lillapojkenpåön I revised your code and it is working fine.

 

However, the thing that is bothering you is logical.

 

My first test was to make sure your right macro was calculated correctly. To do this, I marked each floor tile as red as the square walks, using this code (just before SPRITE 2):

 

temp4 = right
#backtab(220 + temp4) = BG00 + FG_BLACK  + BG_RED 'stones

 

With this code I was sure your right macro is correct. You can see how each stone gets red in turn in the correct place.

 

The second test took me a little longer because a logical fallacy. The important things is: the background is affected by hardware scrolling counters, but MOB's aren't affected by hardware scrolling counters.

 

So this means that any position used for sprites is the real position in screen as if scrolling isn't happening, and that's why we need to adjust sprites with the scrolling offsets. However, if you are going to use a sprite to pinpoint a card on the screen, you need to use the real coordinate.

 

The correct code to make your red sprite to pinpoint correctly the card is this:

 

    temp4 = right * 8 + PF_DIFF
    'temp4 = left * 8 + PF_DIFF
    SPRITE 2,   temp4 + HIT + VISIBLE,    (#playerY AND 255) + ZOOMY2,    SPR16 + SPR_RED

 

Notice the removal of the fine adjustment.

 

So the code was always right. It was only the display code that wasn't right, but you weren't aware of the coordinate differences between the card background world and the sprite world.

 

Probably I'm not using the standard STIC language for describing these, but I'm sure @DZ-Jay can correct any of my non-sense

 

 

 

[Sound effect not working]

When envelopes are used, the "command code" for the envelope should be loaded a single time at the start. Otherwise the envelope is "resetted" continuously creating a "motor" noise.

 

if throw_sound = 1 then

    IF SND = 0 THEN
      sound 4,$0f,$0007
      sound 2,$0BB8,$30
      sound 3,$0800,$0004

    END IF
    snd = snd + 1


if snd = 20 then
  SOUND 4,,0
  SOUND 2,,0
  SOUND 3,,0
  snd = 0
  throw_sound = 0
 end if
end if

 

[2022 Homebrew Awards - Closing and Final Results]

Congratulations to the winners!

 

[Maybe another Chess game?]

4 hours ago, Morpheus said:

Fantastic Oscar!👍👍👍
Are you going to make 200 copies in total?

 

The final number depends entirely on the publisher. But of course I would be happy of reaching 200 copies.

[Maybe another Chess game?]

Boxes are ready! And games are being built!

 

[Upcoming book on Atari 2600 programming (now available)]

On 4/19/2023 at 7:50 AM, turbo graphics 220 said:

I've got this book now, I really want to get into programming on all retro systems. I tried to buy your boot sector books on amazon and they said they wouldn't deliver to my address which was odd since I got a bunch of other books but I might just buy them from another place. I thought amazon just prints them on demand. Anyway book looks great. You also have an intellivision book but I want to concentrate on atari first.

Thanks for your comments!

 

You can also try https://lulu.com/spotlight/nanochess

 

It doesn't require registration to shop.

 

[Maybe another Chess game?]

Overlays ready!

 

Btw one set of four games is available because it wasn't paid.

 

[Upcoming book on Atari 2600 programming (now available)]

Just in case you like fast-camera movements: (and yep, I was unable to change the automatic pronunciation to English)

 

 

[Coming soon, World's Largest Donkey Kong Arcade Game]

I thought someone was playing 24 hours of Donkey Kong on Intellivision 😂

 

My second thought was that someone made a room-size Intellivision. 😅

[Maybe another Chess game?]

Manuals are now printed

 

 

 

[Maybe another Chess game?]

Just I've been informed there are (still) two sets of four games (it was miscounted before).

 

People ordering the four games together will get ROM files for the four games, PDF manuals, and JPG of the boxes, and this is immediately after your payment.

 

BTW cartridges are being built 😉

 

[Tower attack!]

Now that is Apr/02 here is a video of the game

 

 

[Tower attack!]

Hi all!

 

Again, an state-of-the-art game from nanochess, including poliphonic music, big animated sprites, and many colors!!! Even it includes my new feature: Download levels from the Internet using my patented Inteliwifi code.

 

This game is set in the future, when big evil corporations dominate the whole world (wait, it sounds familiar! well I don't mind), and Rev Corp. finally has adquired all the Intellivision cartridges of the world. However, our hero has the last 10 loose Intellivision cartridges in his house, and now the hordes of Rev Corp. clones will try to stole these cartridges!!!

 

The only salvation is the ability of our hero to throw Atari cartridges at light speed towards the clones. (Yes, even in the future, everyone has access to tons of Atari cartridges for just cents a copy)

 

Download it NOW to WATCH THE AMAZING GRAPHICS!!!

 

Enjoy it!

 

tower.zip

[Maybe another Chess game?]

Only remains a single package of the four game set!

 

Last chance!