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rensoup

Unicorns season: Prince of Persia for the A8!

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18 hours ago, rensoup said:

The thing is, with the extended RAM window overlapping the ROM one, I don't see how this would work without changes... and if doing changes, then might as well make it work with existing schemes.

 

The background graphics use extended RAM bank 0 at $4000 for instance and get plotted to the screen at $Bxxx so with your scheme that doesn't work anymore.

 

I understand. Unfortunately, the cartridge area is restricted to $8000-$BFFF.

 

By my side, I will continue developing this project. In case the cartridge works and if you don't mind, I would take a look if it's possible to convert it to this cartridge model.

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3 hours ago, Wilheim said:

I understand. Unfortunately, the cartridge area is restricted to $8000-$BFFF.

 

By my side, I will continue developing this project. In case the cartridge works and if you don't mind, I would take a look if it's possible to convert it to this cartridge model.

Seems a little crazy to make a cart for a single game but it's your time after all...

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On 8/31/2021 at 12:36 AM, Luke210 said:

Yup, i've also experienced this bug

 

 

On 8/31/2021 at 1:11 PM, Level42 said:

Sadly I have neither of those machines....and I lack the time to install emulators etc.

 

Finally got around taking a look at this... it is a game bug and occurs on the C64 as well.

 

Outcome is different though... you fall through the floor never to reappear on the XL but on the C64, the position byte wraps and you end up falling from the ceiling and die after landing on the top floor.

 

I don't know if I'll attempt to fix this because of possible knock-on effects...

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17 hours ago, rensoup said:

Finally got around taking a look at this... it is a game bug and occurs on the C64 as well.

 

Outcome is different though... you fall through the floor never to reappear on the XL but on the C64, the position byte wraps and you end up falling from the ceiling and die after landing on the top floor.

 

I don't know if I'll attempt to fix this because of possible knock-on effects...

Could it be possible to add some sort of boundary checks where if the player is outside of the screen, it's triggering an instant warp back to the last valid position on the screen (eg the spikes) to prevent getting softlocked?
Or is that too much of a big change to the engine to a point more things would break as a result?

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1 hour ago, VinsCool said:

Could it be possible to add some sort of boundary checks where if the player is outside of the screen, it's triggering an instant warp back to the last valid position on the screen (eg the spikes) to prevent getting softlocked?
Or is that too much of a big change to the engine to a point more things would break as a result?

That sounds crazy 🙂. The player being outside the screen can be a valid position, just hang from a ledge which is on the bottom floor and you're outside (the player base Y coordinate is at its feet)

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On 8/30/2021 at 9:24 PM, Level42 said:

After this there was nothing I could do but reload the game.

I managed to reproduce the exact same thing happening on the next run.

I might be able to film it if necessary....

Strange, while both characters disappear, I get the death tune and I'm able to start over...

 

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34 minutes ago, rensoup said:

Strange, while both characters disappear, I get the death tune and I'm able to start over...

 

 

Sadly I can’t see videos posted directly in the forum (IOS devices).

 

I’ll see if I have some time tomorrow to film what happens here…

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1 hour ago, Rybags said:

That video doesn't show here either - Win 7 over 3 different browsers.

It's h264 output from Altirra. Try Brave ?

 

C64 version... (h264 from the same machine but compressed with different software)

 

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That one works.  And no thanks, I use Firefox.  Not interested in yet another 3rd party Chrome based browser.

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On 8/31/2021 at 2:35 PM, rensoup said:

Seems a little crazy to make a cart for a single game but it's your time after all...

Other companies did that with some of their Game Cartridges too, like Nintendo.

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15 hours ago, xxl said:

can you put a savestate out of this error? I can't duplicate it.

 

 

atarivid.avi

it's pretty simple:

-enter screen from bottom entrance

-climb up to second floor

-wait for fighting stance

-move 1 step forward

-parry (UP UP UP UP UP UP ...)

 

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3 hours ago, tjlazer said:

Other companies did that with some of their Game Cartridges too, like Nintendo.

You mean like Starfox which sold 3 million copies ? It does make more sense if your projected sales are between "insane" and "it prints money!"

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In other news, it doesn't look like I've got anymore code to add...

 

Just waiting for assets ( You know who you are 😏 )

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2 hours ago, rensoup said:

You mean like Starfox which sold 3 million copies ? It does make more sense if your projected sales are between "insane" and "it prints money!"

Nah, just trying to give my 2 cents.

 

I do really appreciate your efforts, and that encourages me to bring my help anyway I can.

 

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on real machine I couldn't get it to fail, perhaps not Atari ROM but Altirra rom instead? (vice verso) or some other such issue?

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11 hours ago, rensoup said:

it's pretty simple:

-enter screen from bottom entrance

-climb up to second floor

-wait for fighting stance

-move 1 step forward

-parry (UP UP UP UP UP UP ...)

for me this error is not manifested. could someone do a savestate right before pushing the hero onto the spikes?

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20 hours ago, Wilheim said:

Nah, just trying to give my 2 cents.

 

I do really appreciate your efforts, and that encourages me to bring my help anyway I can.

 

Thanks, although I think a cart designed for a single game should really allow the game to do more than what would be possible without it, in this case it is already possible to make PoP run with 64KB of RAM without any RAM expansion, it's more work but your cart is extra work too because ROM & RAM windows overlap.

 

Didn't know earlier that they couldn't be moved.  It would have been nice to have a RAM cart usable with any software (although I guess it would been done decades ago had it been possible)

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20 hours ago, _The Doctor__ said:

on real machine I couldn't get it to fail, perhaps not Atari ROM but Altirra rom instead? (vice verso) or some other such issue?

It looks like @Level42 got it on a real machine though... plus it happens with the C64 version too.

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so it's an original bug from back in the day rather to say since inception?

Edited by _The Doctor__

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59 minutes ago, rensoup said:

a cart designed for a single game

Obviously it isn't, its a variant model that simply has potential for lots of other things, PoP just being the first ;)

 

 

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On 9/5/2021 at 9:55 PM, rensoup said:

It's h264 output from Altirra. Try Brave ?

 

C64 version... (h264 from the same machine but compressed with different software)

 

It plays perfectly on FireFox Win XP32.

 

 

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4 hours ago, _The Doctor__ said:

so it's an original bug from back in the day rather to say since inception?

The C64 version was started by hacking the A2 version so yeah... there are many bugs in the original, not a surprise given its complexity.

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