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Rybags last won the day on September 1 2016

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  1. Looks pretty good, it even has hills. It's reasonable to think it could run on our machine as well or better. We have a slight speed advantage in standard graphics mode and the Plus4 has no PMGs.
  2. Self-modifying code version of the above also 12 cycles. Or 10 if the DLI code is on z-page.
  3. NTSC palette I agree is entirely possible, what I meant was a dual palette probably isn't.
  4. I didn't realise the newer version had the select jumper. But from what I can determine, it has onboard clock crystals to cover both systems which is what the jumper is for. Now the thing I wonder is, you could probably run a PAL machine at NTSC speed for a handy little overclock and the VBXE video signal should still be perfectly valid.
  5. Additional - AFAIK the core is at capacity as I requested bug fixes & extra features... but can't be done.
  6. Antic isn't emulated - VBXE gets its socket as that's the obvious way to give the bus access it needs as well a the AN signaling which is for GTIA PF graphics generation. The core doesn't need to be system specific (aside from the palette differences) since it can sense PAL by the number of scanlines between VSync commands.
  7. There's no provision for screen codes as such. And no provision either for doing such things as adding an constant value, setting or flipping the high bit or other tricks that modern cross-platform assemblers usually have as standard. The OS just runs the character codes through a translation based on the top 2 bits and text mode in use, so you could do the same. Try and put all the text screen assets in a continuous block then do a single run over at startup time assuming it's a Ram-based program.
  8. I'm not sure if I looked further into this. In theory the palette should be in the flashable firmware so you could just put your own one in there and flash into a vacant slot and try it out. Possibly the palette is compressed in some way or procedurally generated which could make things a bit trickier.
  9. Unsure if this is commonly known info (from that link) C012294B-01 AMI C012294-03 Signetics C012294-22 OKI C012294-31 IMP There must be others too.
  10. Maybe you'll have to create one? Get an existing stereo song, modify the instruments. Then create a merged executable with the original, modifying the addresses for the extra 2 Pokeys.
  11. I've got my doubts. I'm not sure that the boss fight methodology was even conceived for the game. You can stand part way up a ladder which makes you invulnerable to the stomping, so maybe that was to be part of the strategy. From memory you can also accumulate a surplus of swords especially towards the end so maybe that was to be part of it as well. I used to play the game a lot and was disappointed that there was no way to complete it. Then years later, almost equally disappointed at the feeble effort that was the commercial release of Montezuma's Revenge. It's almost an ironic twist to the whole saga and a play on the name - create a proto of a promising game that leaves you hanging for the conclusion but then get fed an end product that fails to deliver.
  12. Don't forget these guys http://atari.vjetnam.cz/index.php?frame=games
  13. I bought (2nd hand) the book "Fundamentals of Interactive Computer Graphics" by James D. Foley, Andries van Dam about 20 years ago (original publication was 1982). The target systems were more along the lines of high end workstations of the time, and the programming examples are more along the lines of psuedo-code and explaining the algorithm than any specific language. There's colour plates with sample images and the Atari 800 even makes an appearance. The thing about 3D graphics, and that's inclusive of wireframe all the way to bump-mapping, light sourcing and reflection, occlusion, z-buffer processing etc etc is that the techniques predate the modern hardware based equivalents by decades. The shiny new nVidia is just doing the same thing that software was doing 40 years beforehand (though of course about 100,000 times or more faster).
  14. All I can say is bring it on! And if it takes a 1 Meg cartridge and/or 320K Ram then so be it. Quality over compromises.
  15. The next problem you'll face - regardless of how tall the screen is, the OS routines will only support 320x192. To draw in the extra area you'd need to set the screen base forward then allow for the new origin with your graphics operations. And contiguous video memory - you'll hit trouble once you cross into a 3rd 4K region since 40 won't divide into 4096 evenly. But, given the OS limitation as mentioned, you could leave padding between the normal 192 and extra scanlines since you need to change the OS screen pointer to do operations there.
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