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Alien Swarm + JAC! fixes

5200 conversion

7 replies to this topic

#1 playsoft OFFLINE  

playsoft

    Moonsweeper

  • 370 posts
  • Location:UK

Posted Mon Aug 11, 2014 3:51 PM

This is a 5200 version of Alien Swarm with JAC!'s fixes as described here: http://atariage.com/...m-hack-request/

 

Instructions can be found here: http://www.atarimani...-swarm_202.html

 

JAC! provided me with the source code which I've modified for the 5200 and tested on my 4-port with Atarimax Ultimate SD.

 

Edit: updated version below



#2 Charlie_ OFFLINE  

Charlie_

    River Patroller

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  • Location:NJ, USA

Posted Mon Aug 11, 2014 4:57 PM

Thank you  Paul. :thumbsup:



#3 Aking OFFLINE  

Aking

    Moonsweeper

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  • RetroLover
  • Location:Nintendo Switch and Atari Land

Posted Tue Aug 12, 2014 8:13 AM

amazing work, great game Paul

just had hopes for a JAC! video about the hacking and conversion...



#4 slampam OFFLINE  

slampam

    Moonsweeper

  • 354 posts

Posted Wed Aug 13, 2014 10:19 AM

After awhile of play the colors go funny and the screen goes blank but the game keeps playing unseen.

#5 Charlie_ OFFLINE  

Charlie_

    River Patroller

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  • Location:NJ, USA

Posted Wed Aug 13, 2014 8:45 PM

After awhile of play the colors go funny and the screen goes blank but the game keeps playing unseen.

I haven't been able to get at my 5200 yet so I can try this. I'll check it out soon and see if  get the same problem.



#6 playsoft OFFLINE  

playsoft

    Moonsweeper

  • Topic Starter
  • 370 posts
  • Location:UK

Posted Thu Aug 14, 2014 4:26 PM

I was able to reproduce it - it occurs when you've got far enough in the game that the snake starts planting red saucers.

 

It's a bug from the original game. There is a table of screen addresses and when it plants a saucer (at the bottom of the screen) it reads beyond the end of the table and ends up incorrectly writing to zero page locations. Once the saucer is bouncing around the screen it is fine, it is only the initial placement of it where the issue occurs.

 

The 5200 and A8 use zero page differently which is why the bug is more evident here, although it could still lead to problems on the A8 original.

 

I made the table of screen addresses longer and it now seems fine, as far as I can get in the game anyway.

 

 

Attached Files



#7 JAC! OFFLINE  

JAC!

    Stargunner

  • 1,833 posts
  • Always looking for GFX and MSX for my demos
  • Location:Lebach, Germany

Posted Wed Sep 24, 2014 10:58 AM

Hi there,

 

"poked" by Aking's orginal request and thanks to Paul's excellent help I managed to create a version that compiles both to 5200 and 8000/XL. It includes some more fixes (e.g. 4 digit energy) and is available here:

 

http://atariage.com/...uest/?p=3078433

 

I hope it works on real HW. I never had a 5200 and didn't even know how the controllers work :-)

 

Now I could a least think of a video tutorial. But am actually lacking the time. Yet, the full commented source for the XL/5200 specific parts in the download will be a good start. 


Edited by JAC!, Wed Sep 24, 2014 10:58 AM.


#8 walter_J64bit OFFLINE  

walter_J64bit

    Quadrunner

  • 5,218 posts
  • Location:Goldsboro NC

Posted Wed Sep 24, 2014 5:16 PM

Alien Swarm , I've haven't played this A8 game yet.





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