Question about Combat's programming

[MaximRecoil]

Are the tanks one object, or are the barrel and the rest of the tank two separate objects? The reason I ask is because my "heavy sixer" is acting strange. I posted about it in the "Hardware" section of this forum, so I'll paste what I posted there:

 

In Combat, in games 1-5 (with the light green background), the player 1 tank (red) barrel turns the same color green as the background when you rotate (when the barrel is facing strictly to the left or to the right is the only time it is red like the rest of the tank). Also, the bullets it fires are always the same color green as the background, making them difficult to see (it is only due to RF artifacts that you can see them at all). The player 2 tank (blue) doesn't have these issues. Its bullets are blue (the same color as the tank, just as they should be), and its barrel doesn't change color as it rotates. None of my other 5 Atari 2600s have these issues.

 

Swapping the TIA chip with one from a light sixer didn't make a difference, and neither did swapping the RIOT chip or the CPU. Also, the issue disappears in B&W mode, for whatever that's worth.

 

 

If the tank is just one object, I don't see how just its barrel could change color as the tank rotates. In any event, I'm hoping that knowing more about how the game was programmed will help me figure out what's wrong with my heavy sixer hardware.

Edited October 12, 2015 by MaximRecoil

[+SpiceWare]

tanks are one object. You can use Stella's Debug Color Mode to determine things like that. See reply 45 in this other topic for more info.

 

 

[MaximRecoil]

tanks are one object. You can use Stella's Debug Color Mode to determine things like that. See reply 45 in this other topic for more info.

 

Combat (1977) (Atari).png

 

Combat (1977) (Atari)_1.png

 

Thanks. Do you have any idea how only the barrel of the tank could be changing color as it rotates?

[R.Cade]

That's really strange... I would have expected the TIA swap to fix something like that. I guess there must be support circuitry at fault here... (obviously)

[+bcombee]

Did you try a different TV? That looks like a color phase detection issue on the monitor end, not an Atari problem.

[MaximRecoil]

Did you try a different TV?

 

No, but I tried 5 other Atari 2600s with the same Combat cartridge (3 light sixers and 2 4-switch woodgrain versions), and none of them had this issue (nor any other issue, for that matter), which rules out the TV and the cartridge.

Edited October 12, 2015 by MaximRecoil

[MaximRecoil]

I fixed it. See this thread for details.