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DEBRO

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DEBRO last won the day on March 21 2010

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About DEBRO

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    Stargunner

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  • Gender
    Male
  • Location
    Atlanta, GA
  • Interests
    Atari game programming

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  1. Hi there, I have planned to move all my source code (disassemblies and original work) to Github. I only have 5 at the moment but more will come. Alternatively, you can find links to my disassemblies on AA from this list. https://github.com/DNSDEBRO Disassembling 2600 Games Topic
  2. Hi there, I'm sure something like this has been shared or posted before. Still, I thought I'd share a spreadsheet I created to help me with player color clock position values. I used something similar when constructing Climber 5 and Pacman4K to help me with object positioning and playfield graphic positions. Changing the "RESPx strobe ends at cycle" value will automatically compute the machine cycle and color clock position for me. Using this, I can then play with position values or RESPx strobe values to get the results I'm looking for. Atari_VCS_Horizontal_Positioning_Chart.xls
  3. Hi there, Sorry...my cycle counts were off. Yes, you are strobbing RESP0 at the desired cycle 23. Really? My calculations show a value of 134 is the maximum before you spill to another scan line. A value of 134 should strobe RESP0 at cycle 63 with a 8 pixel right shift. Adding 6 more cycles for the RTS you are now at cycle 69 on the return with enough time to do a WSYNC. A value of 135 should strobe RESP0 at cycle 68 with a -6 pixel left shift. Adding 6 more cycles for the RTS you are now at cycle 74 on the return and no time to do a WSYNC without spilling to the next scan line.
  4. Hi there, Constant cycle counting.
  5. Hi there, If I'm understanding correctly, your new routine hits the player reset at a minimum of cycle 22. This would give a player horizontal resolution of 60 - 224 without spilling over to the next scan line. The importance of hitting the player reset at a minimum of cycle 23 gives a player horizontal resolution of 63 - 227 before spilling over to the next scan line.
  6. It is me. My Stella had the fire button configured to a different button than normal.🤦‍♂️
  7. First let me pick my jaw off the floor. This is impressive!! I would have never thought Robotron would have existed on the VCS. Am I the only one experiencing control issues in Stella? The SELECT key doesn't seem to work for me. Also, I can't seem to fire missiles. Even when I place the left difficulty on A, the continues to fire in the direction I was pressing when I set the left difficulty.
  8. Hi there, Thank you @ferghead for sharing this with the community. I'm curious to know about these game graphics and why they changed or who changed them. This may be lost with time. Thank you @Ballblaɀer for recommending I take a look at this. I originally thought this would be done quick. I didn't anticipate too many differences from the released version. Of how surprised I was to find so many differences.
  9. Hi Thomas, I noticed a similar coding in Astroblast. In the TimerWait routine there is a NOP instruction after the read to T1024T expires. This is located as locations $F453 - $F460. Since your display rolls in your example without your NOP; try modifying the Astroblast code by removing the NOP at $F458 and see if the screen rolls for you.
  10. Hi Thomas, Sorry, my hardware isn't setup at the moment for me to try.
  11. Hi Thomas, This is strange. BTW, is this the same VCS and TV you used to test SWOOPS!? I remember you reporting a similar issue on [stella] that I believe we never diagnosed completely. (Without looking it up) I believe we thought it had to do with activity during VSYNC or not disabling the TIA. I see you are disabling the TIA in this code though. This is very strange.
  12. Hi David, I haven't been following and keeping up as I planned. This still looks promising. Sorry to read you were under the weather. Hoping you were able to shake the sickness and continue with this.
  13. Hi there, I've been reverse-engineering Missile Command off and on. It's one of the many on my to do list. Rob does a similar technique of a linear question found in Activision's Laser Blast, Fishing Derby, and Pitfall! Look at my reverse-engineering of Laser Blast. It may help. Start looking at label .determineAttackerLaserDirection. This is where David Crane determines the direction of the attacker laser and the slope. Then in the kernel at .drawLeadShipKernel he uses the tankLaserSlopeFractionValue to increment tankLaserSlopeIntegerValue. When a carry is determined (i.e. time to increment the integer value) he sets the HMM1 register to fine adjust the tanks laser.
  14. Hi David, You should be able to this without flicker. Hopefully @Atarius Maximus is okay with me linking directly to his site. Take a look at my (embarrassing to look at) source for Climber5 or Joe Grand's UltraSCSIcide. We both used Oystron by Piero Cavina as a model. They are good examples of vertically separated sprites. Also look at my reverse-engineering of Atari's Air-Sea Battle or 20th Century Fox's Turmoil. These are good examples as well.
  15. Hi there, I would have thought the title was done with tiles.
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