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Wrathchild

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Wrathchild last won the day on December 7 2022

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    Reading, UK.
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    Porting games the A8 never had

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  1. Yes, text does state "...has no relation to the 1985 Atari arcade game of the same name"
  2. Happy to take a look at this and the workaround, is history on github?
  3. My biggest beef with that was probably Paperboy
  4. https://www.atariprotos.com/5200/software/roadrunner/roadrunner.htm
  5. A fair few http://www.atarimania.com/list_games_atari-400-800-xl-xe-p_total-page-step-genre_50-1-25-28_8_G.html
  6. You could get the vector from the device table at $E400, the "keyboard get" being at $E424. This is a push and RTS value and so -1 from the actual address, i.e. stored lo/hi as $FC $F2 for $F2FD. GetKeyVec: JMP $FFFF InitGetKey: LDA $E424 CLC ADC #1 STA GetKeyVec+1 LDA $E425 ADC #0 STA GetKeyVec+2 RTS TestGetKey: JSR InitGetKey JSR GetKeyVec ...
  7. You can read the chip id and make a decision (sector #) based on that
  8. I coded this across for my NYD 2024 entry: https://demozoo.org/productions/335309/ Taken from: https://www.youtube.com/watch?v=1maqxva0W3c
  9. Isn't the true horror hearing the knocks on the door of a good pilot slow to nothing 🤔
  10. @Steril707 needs to be a clearer about what they are trying to achieve My feeling is it could be something like @popmilo experimented with when working on Wonderboy's level scrolling using a font per line.
  11. Kroah might have done some... I have too in looking at what's needed for a cartridge port but not gone into gameplay calcs. I did study the map building however and that uses rules for placement etc and runs multiple passes over the data, so re-loads/saves sectors as it builds.
  12. 256 chars still a problem as 40 chars x 6 lines is only 240. On the C64 the 'bitmap' is 8 bytes down then 1 across (BBC is similarly arranged). x 0 4 8 12 152 156 y 0 0 8 16 24 ... 304 312 1 9 17 25 ... 305 313 2 10 18 26 ... 306 314 3 11 19 27 ... 307 315 4 12 20 28 ... 308 316 5 13 21 29 ... 309 317 6 14 22 30 ... 310 318 7 15 23 21 ... 311 319 8 320 328 336 24 ... 624 632 321 329 337 25 ... 625 633 322 330 338 26 ... 626 634 323 331 339 27 ... 627 635 324 332 340 28 ... 628 636 325 333 341 29 ... 629 637 326 334 342 30 ... 630 638 327 335 343 21 ... 631 639 16 640 648 656 24 ... 944 952 641 649 657 25 ... 945 953 So to write on the 9th, 17th, 25th line requires a multiple of 320. Hence all the data is contiguous but for the A8 'fake' char based bitmap model a few font chars are unused and so the calculations need adjusting to take that into consideration. With Sentinel this isn't so bad as the game uses a table of "n x 320" as a lookup and so this is why the screen rendering worked. The issue is the scrolling code block copies and hence can use the assumption of the contiguous areas to do things quicker.
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