[Searching for the "AI" in "Video Olympics"]

Great! This works!

[Searching for the "AI" in "Video Olympics"]

50 minutes ago, splendidnut said:

You're trying to skip the routine too early.  F1F2 needs to be hit because it loads that data that is saved at F202.  It would work better if you placed your jump code patch at F1F4.

Then to Pong Robot stops moving.

I thought of adding/subtracting #$0:

f1fe    adc #$00
f200    sbc #$00

[Searching for the "AI" in "Video Olympics"]

Just now, Microprofessor said:

The common typo! How often have I made it??

 

Would it be possible to bypass the routine with:

f1e3: jmp $f202
f1e6: nop

... make the "Pong Robot" invincible?

Hmm... the game freezes if I change this. The routine seems to be used by other parts of the program, too.

[Searching for the "AI" in "Video Olympics"]

The common typo! How often have I made it??

 

Would it be possible to bypass the routine with:

f1e3: jmp $f202
f1e6: nop

... make the "Pong Robot" invincible?

[Searching for the "AI" in "Video Olympics"]

Great, thank you. In the next days I will tinker around with the code in Stella to see what happens if I change the mask.

 

µP/Stefan

[Searching for the "AI" in "Video Olympics"]

  

Hi,

 

I am searching for a specific function in the "Video Olympics" code: The AND mask that is used to "diffract" the Robot's paddle from the vertical ball position.

 

I found a hint to this in a quote from Bogost's/Montfort's "Racing the Beam":

 

Quote

Robot Pong’s AI slows itself down, never quite following the ball exactly while still appearing to do so.

The effect is accomplished very simply. When the ball is first served, the computer positions the AI paddle so that its top edge is vertically aligned with the ball. To move the ball, the program adjusts its vertical position by an offset value each frame of up to ±2 scan lines. This value corresponds with the direction in which the ball is moving (up or down),

as well as with its speed. Each time the kernel adjusts the vertical position of the ball, it also adjusts the paddle.

To help simulate the human error inherent in precise paddle posi- tioning, the AI paddle skips its vertical adjustment every eight frames. The resulting behavior is visibly unnoticeable, but it allows the computer player’s aim to drift enough that it occasionally misses the ball. It is also technically trivial to implement, requiring only a simple mask using the binary AND operation, for which there exists a corresponding 6502 instruction. The programmer can test to see whether the result is zero with another single opcode, branching if needed to skip the instructions that move the paddle.

Even this behavior must be modified slightly for the game to work at all. If the AI player simply stopped tracking the ball every eight frames, it would be hopelessly out of sync within a few seconds. To prevent this, the AI follows a secondary ball-tracking plan near the top and bottom of the playfield. If the ball collides with one of these walls when the paddle is also aligned with it, the paddle readjusts, recovering from any drift that had accumulated since the ball last struck the wall. The result is a stochas- tic misalignment and realignment of computer paddle and ball.

Together, these two techniques produce a convincing robot player of Pong—one that makes mistakes, but not too frequently.

(p. 39–40)

 

Does anybody know where this AND mask is located within the code? (And is there a disassembly of the "Video Olympics" code with comments anywhere on the internet?)

 

Thanks!

 

µP/Stefan

[Vectrex lightpen with buttons]

2 hours ago, rastislav said:

Hi guys, I have made a list of you interested in buying a lightpen and I will start making and shipping them to those still interested, just pls tell me again which version of the lightpen would you like (and if you like the version with the connector, on which side you prefer to have it) and if you like righ or left handed (difference is only on which side of the buttons is the Vectrex logo). The prices are: 100$ for A version, 125$ for C version and 150$ for B version. Shipping worldwide is free. 

I'd like to order one of the "RZ Pen-B".

 

µP

[Ultimate Cart (SD multicart) - preorders thread]

Please add me to the order list.

[Picture of "E.T." cartridge board needed]

Thank you so much for your helpful hints!

[Picture of "E.T." cartridge board needed]

noone?

[Picture of "E.T." cartridge board needed]

Hi,

 

for a lecture about the Atari VCS game "E.T." I need a photography of the cartridge's circuit board (upper side with the ROM chip).

 

Does anyone know where I can find one or can anybody take a picture of it and post it here for me?

 

THANKS!

 

µP