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A8 Donkey Kong Jr. Arcade HACK


darryl1970

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Also note that the position of player's 0 and 1 (left half of JR) are used in the boundry computations. This is why the boundry limits are offset to the left. On an NTSC screen, the boundry's are offset upwards by 16 scan lines.

 

Following the GTIA HPOS values for all 4 players - it looks like Jr is composed of all 4 players - is that true? P0+P1 for left half, P2+P3 for right half? P2/P3 are 8 pixels further right than P0/P1.

 

I do see how the left half of Jr - thus P0/P1's HPOS - is used to calculate boundaries, as mentioned above. (I thought that the literal hex values seemed shifted to the left a bit when I was testing!). Thus on stage 1 platform 1 , Jr's HPOSP0 = 59 and he is still safe standing at the edge. But if you move to $5A (the right boundary), he falls.

 

This is always true, regardless of which animation frame Jr is stuck on at the edge. If he has his feet together, you can more clearly see that one more step and he'll slip off. But if he is in his wider arms-out frame , it looks like you might be able to step a bit further - but Jr is still at HPOSP0=$59 and if you move rightwards one more pixel, he'll fall to his doom! If Jr jumps standing still, he seems to always default to his feet together frame when he lands, so that is one way to visually be sure you are at the edge.

 

If the edges were extended by even +$1, that would reduce the slippage. +$2 would make the game even easier, but testing would reveal if too much.

 

also adding to the findings above, I also noticed that if you extend the earlier platforms (like Platform2 for example) across the screen, the game engine doesn't let you stand on platforms 3 , 4 or 5, and also doesn't allow you to grab a vine, even though you can jump to them. This makes me think the game tracks which was the last platform you were standing on. You can jump from Platform2 to 3 , and Platform 3 to 4. But if you try to jump from extended across-screen Platform2 to Platform 4 or 5, the game doesn't recognize it.

 

However, being practical, the extending of the platforms by just +$1 or +$2 won't cause these types of bugs.

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Following the GTIA HPOS values for all 4 players - it looks like Jr is composed of all 4 players - is that true? P0+P1 for left half, P2+P3 for right half? P2/P3 are 8 pixels further right than P0/P1.

 

I do see how the left half of Jr - thus P0/P1's HPOS - is used to calculate boundaries, as mentioned above. (I thought that the literal hex values seemed shifted to the left a bit when I was testing!). Thus on stage 1 platform 1 , Jr's HPOSP0 = 59 and he is still safe standing at the edge. But if you move to $5A (the right boundary), he falls.

 

This is always true, regardless of which animation frame Jr is stuck on at the edge. If he has his feet together, you can more clearly see that one more step and he'll slip off. But if he is in his wider arms-out frame , it looks like you might be able to step a bit further - but Jr is still at HPOSP0=$59 and if you move rightwards one more pixel, he'll fall to his doom! If Jr jumps standing still, he seems to always default to his feet together frame when he lands, so that is one way to visually be sure you are at the edge.

 

If the edges were extended by even +$1, that would reduce the slippage. +$2 would make the game even easier, but testing would reveal if too much.

 

also adding to the findings above, I also noticed that if you extend the earlier platforms (like Platform2 for example) across the screen, the game engine doesn't let you stand on platforms 3 , 4 or 5, and also doesn't allow you to grab a vine, even though you can jump to them. This makes me think the game tracks which was the last platform you were standing on. You can jump from Platform2 to 3 , and Platform 3 to 4. But if you try to jump from extended across-screen Platform2 to Platform 4 or 5, the game doesn't recognize it.

 

However, being practical, the extending of the platforms by just +$1 or +$2 won't cause these types of bugs.

Yes. Junior is made up of all 4 players, and that explains a lot. In the arcade version, the snapjaws do not collide with Jr.'s back legs. I know that the A8 is not as forgiving.

I know the latter was a little outside of the scope of ground slippage, but you gotta love scope creep! :)

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Hey! I have been pretty busy this weekend, but I made some time to check out the new boundaries. I think I prefer extended by two.

I played the arcade tonight, just to get a feel. I think it feels the most arcade.

 

Here's version 10!

 

Playsoft tweaked Mario's head color to be all one color, and he helped me to plug the floor offsets into the program.

I tweaked the floors to be a little more arcade accurate in design.

(The girder at the top was due to the color changes. It looked weird with the two shades of floors, so I borrowed a girder from DK!)

 

This version includes the new platform data, thanks to Tep392 and Cafeman!!

 

Turning out to be a great community effort!

 

post-13491-0-49558800-1449975356_thumb.png post-13491-0-49833900-1449975366_thumb.png

 

DkJr_V10.xex

 

Playsoft is going to get the graphics for Mario's hideout and the intermission when he has time.

Let me know if there's anything else that you guys have to make this more arcade accurate!

Edited by darryl1970
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I like V10. But its still really hard! I have a hard time outwitting the snapjaws on stage 1, and I have a hard time getting past the birds on the spring stage. And, even though you've improved the platforms, I still fall off and die, so the platform adjusts certainly didn't make it TOO easy.

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Another existing glitch is the flashing life on the top left at end of level.

 

v10 some feedback (playing on PAL/130XE/CRT)

On the first go after loading Jr is stuck for a while and can't move!

I didn't like the colours - though it looks a bit dull.

Didn't like the new snap-jaws, look a bit weedy - but I guess this is what they should look like?

The lives remaining heads don't look like anything!

 

Most importantly it plays well though :thumbsup: 81,900 didn't fall off once and wasn't being overly cautious.

 

Is it a tad faster than it was?

Please can you make reset reboot too ;)

 

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First: Totally love all the work you guys putting in these updates of old favorites of mine !!!

 

I do have one remark though: I think "improving" the game mechanics is sometimes not a good idea. F.I. the DK "arcade" version for the A8 completely screws up the game because of it's changed collision detection, because hammers do not hit barrels which are on the overhead girders anymore....

Anyway....I am very much used to the game mechanics as they are. It would be awesome to have an option to select "improved" game mechanics or original game mechanics.

 

 

Now let's see if I can play this on an emulator, as my hardware is tucked away at the moment....

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Just played both Popeye and DKjr. and what can I say..........absolutely brilliant work !!!!! I actually prefer Popeye's collision detection for the punches...they were very extreme on the original...

 

Well done well done, keep up the great work !!!!

 

Can't wait to play these on original hardware and using a proper joystick :)

Edited by Level42
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I really enjoyed your tweaked version of Popeye, but I am afraid this is fix-up is not working for me :_(

 

The new colours are drab, and whilst the new snap-jaws are nearer the arcade in shape their coloration is weak, likewise Mario, he looks "weird" now. The feel in V10 is odd, probably a result of the platform collision tweaks, I cannot seem to un-learn 32 years of training!

 

I can see some tweaks to the DKJ sprite which are nearer the original, and they look nice :-D

 

If you can add DLI to tweak the colours then I suggest you do that, but if not the new colours are not as good a compromise as the original IMHO...

 

sTeVE

 

P.S. Looking back at the thread the colours in V7 seem more like the arcade's vibrancy and lose the Atari Purple ;)

Edited by Jetboot Jack
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I really enjoyed your tweaked version of Popeye, but I am afraid this is fix-up is not working for me :_(

 

The new colours are drab, and whilst the new snap-jaws are nearer the arcade in shape their coloration is weak, likewise Mario, he looks "weird" now. The feel in V10 is odd, probably a result of the platform collision tweaks, I cannot seem to un-learn 32 years of training!

 

I can see some tweaks to the DKJ sprite which are nearer the original, and they look nice :-D

 

If you can add DLI to tweak the colours then I suggest you do that, but if not the new colours are not as good a compromise as the original IMHO...

 

sTeVE

 

P.S. Looking back at the thread the colours in V7 seem more like the arcade's vibrancy and lose the Atari Purple ;)

Thanks. Glad you liked Popeye.

 

I would like to get this as close to the arcade colors as possible. Sometimes I do feel that the floor is a little too dark.

Playsoft has executed some DLI's. He said adding more seems to cause slowdown.

I changed a lot in Popeye before the final, so I'll probably do the same here too.

Sometimes I have to look at it with fresh eyes.

 

However, I have been a little more on the go lately, so it's harder to make the time.

Just curious. Do you play on NTSC or PAL?

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Just played both Popeye and DKjr. and what can I say..........absolutely brilliant work !!!!! I actually prefer Popeye's collision detection for the punches...they were very extreme on the original...

 

Well done well done, keep up the great work !!!!

 

Can't wait to play these on original hardware and using a proper joystick :)

Thanks! It's still a work in progress. :)

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Here's version 12.

  1. Color Changes
  2. Graphic Changes (Update Mario's Hideout, Birds, Intermission, and a few tweaks here and there!)
  3. Corrected platform boundaries

post-13491-0-32740900-1450276449_thumb.png post-13491-0-55353700-1450276466_thumb.png

 

post-13491-0-63854000-1450276484_thumb.png post-13491-0-18977400-1450276501_thumb.png

 

Before / After

post-13491-0-08319500-1450276519_thumb.png post-13491-0-56611200-1450276534_thumb.png

Intermission graphics HERE

 

Edit: Almost forgot the File!!

DkJr_V12.xex

 

Edited by darryl1970
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I like the birds now. I know the other version was a bit closer to the arcade, but I always thought the arcade birds were ugly too.

Thanks. These are actually modeled after the birds on the locks screen. The other birds were modeled after the birds from the Springs, and I added features from the lock birds. I really hated them.. I thought I made birds that looked like giant, winged cockroaches! LOL.

 

Thanks. Glad you like them better too.

 

The colors are trickier than I thought, because tweaks look better in one place, but they look worse in another. I tried to find the best MIDDLE ground. :)

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