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Galaxian calibration fix

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I heard a while ago that the wonky control in Galaxian is due to a case of two swapped pointers somewhere in the machine code. Has there ever been a rom which had this problem fixed?

If not, how hard would it be to fix? It sounds like something someone with a hex editor could do.

 

 

Thanks,

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My Galaxian works fine too. The joystick sideways control potentiometer has to centered exact to get the faster movement at both left and right extremes. You can tweak your 5200 controller by taking it apart and center the swing arm controlling the pot. If a Wico stick, the slide bar on the side can adjust it.

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Anyone ever try to address this in an emulator?

 

I've been seeing this in OpenEMU as well as our own code (Argon) and it was driving me nuts until I saw this thread and another mentioning Galaxian having calibration issues/being sensitive to calibration.

 

The behavior is that sometimes you'll be playing and if you press right, the ship will go left, and if you provide no input, it will drift to the right. It doesn't happen every game, but if you play long enough (in emulation with digital controls) it eventually happens.

 

I presume this is what people are talking about?

 

This is with our 8-way digital control -- we're still tweaking our analog support.

 

It was especially nutty as it would seem to either start happening, or stop happening when you lose a ship, and the clear or resume having the issue on the next ship.

 

I'm wondering if perhaps we need to force the POKEY POT values to be "centered" at machine initialization.

 

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Galaxian is best played with the trakball, in my opinion.  There are no issues when you use that, assuming you have or can acquire one.

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46 minutes ago, Ryan Witmer said:

Galaxian is best played with the trakball, in my opinion.  There are no issues when you use that, assuming you have or can acquire one.

Does the trackball work in proportional mode with 5200 Galaxian, or act as a digital joystick?

 

We have found the issue... The game tries to recalibrate the analog stick range on every new ship spawning. So if you have a digital stick, and have the stick right or left at that time, it treats that as "center" and then you are stuck with the game thinking that the "center" is far right (or far left) and thus you then can't move in that direction, and "center" gets treated as moving the other direction.

 

We're trying to think of a clever way we could work around that in emulation. For sure, we could apply a patch to NOP the calibration code in the game at runtime, but it would be nice if we could come up with a more generalized solution.

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By selecting the trackball in Emulator Altirra, you can get nice digital controls with the keyboard cursor keys. Or, you can assign a mouse and get proportional control similar to the analog 5200 stick.

 

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