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About Dionoid

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    Leiden, Netherlands
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    Game development!

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  1. Most of the PAL Super Football cartridges made in Hong Kong do have that "Atari 7800" on the top label. The ones made in China all correctly show "Atari 2600". Sorry, not rare
  2. I really hope someone will write a book about Project AtariBox when the dust settles.
  3. Thanks for the siren code, Thomas! I can see that you're updating the frequency 5 times each frame, which probably gave you the best results. I have a similar experience, and found that around 8 frequency-updates a frame works best for mixing frequencies. If you update the frequency more often (e.g. 50 times a frame) the distortion will get really bad. Here's my code to generate a "falling down" sound effect: falldown_sfx.asm Anyway, I've switched to using 4-bit PCM sound, which has less 'blips' (but isn't as clean as the TIA waveforms)
  4. Lode Runner is also one of my favorite games on the Commodore 64! I wanted to port this game to the '2600 for a long time :-) I'm currently working on implementing the guard AI, based on code from this book:
  5. @Trebor Thanks for the link to the 'Testing CRT Screen Size' page by Thomas Jentzsch. I actually searched the AA forum for information before, but this specific page didn't came up in the results. I have to improve my AtariAge Search-Fu 🙂 Anyway, this is good information! From Thomas' results, it seems 206 visible scanlines should be well acceptable for almost all TVs. @easmith @sramirez2008 Thanks for your responses; I really appreciate it. It is good to know that both your results were similar.
  6. I guess iesposta was referring to my mp3 sample, that has a higher pitch and makes the pops more noticeable. IMO frequency mixing works better for lower pitch notes (like you have used in Star Castle Arcade), where the pops are both less frequent and mingle in with the sound. Personally I never noticed the pops in Star Castle Arcade; only when I was actively listening to it 🙂
  7. Hi, I've started working on a new game for the Atari 2600 that uses 206 scanlines of visible display (instead of the traditionally recommended 192). I know that most CRT televisions can display more than 192 lines, so I've increased the visible screen by both decreasing the scanlines for Vertical-Blank (start of display) and Overscan (end of display). I've been playing around with the display, which now looks fine on my European PAL CRT, but I really like to know if this also works on NTSC televisions. So, if you have an NTSC Atari 2600 and CRT television, and also own a Harmony cartridge, you could help me out: I've attached 3 NTSC versions of my work-in-progress game (note that I probably shouldn't call it a game, as it's not playable) fools-gold-ntsc-40.bin fools-gold-ntsc-44.bin fools-gold-ntsc-48.bin I'd like to know which of these 3 versions (40, 44 or 48) displays fully on your CRT, and which one has the most equally divided margins. Note that for an optimal display, both the big text at the top (spelling FOOL'S) and the score-bar at the bottom should be fully readable (see screenshot below) A photo of your display would be appreciated, but not required (just tell me which version looks best on your display, assuming at least one of these versions displays fully on your CRT) Also let me know if none of these versions display correctly. Also, when you press the fire button on the title screen, does the circular-wipe effect (a.k.a. iris shot) shows without any screen rolling? Thanks for the help !!!
  8. Thanks for the link about the non-linear volumes! Star Castle has the same popping sound, but it's less noticeable because of the lower tones. I can reproduce the sliding sound of Star Castle almost exactly, including the popping sounds, if I mix the frequencies 4 times a frame. Maybe I have sensitive ears 🙂
  9. Hi Thomas, it makes no difference if I set AUDC0 and AUDV0 each frame or just once. The 'popping' sounds are still there. This is the mp3 of my results using frequency mixing on a clear waveform to generate a sliding sound. The popping is way less on lower frequencies, or if a use a waveform other than 4/5 or 12/13. But that is not what I want sliding_sound_freq_mixing.mp3 Also I found that frequency mixing works best if you update the frequencies 4-8 times per frame (so "the more the better" doesn't seem correct). I found that mixing frequencies (e.g. quickly switching between frequencies 14 and 15 within the same waveform) also causes a soft pop, which is only noticeable when you switch frequencies back and forth a lot. 4-bit PCM samples give me better results here: the 'pops' are gone, but the sound isn't as clear as using the normal TIA waveforms. I also did some experiments by playing different frequencies on voice 0 and 1, and then slowly mixing the volumes of voices 0 and 1, so it simulated a note-slide. This kind of works, but the results weren't that great. I think e.g. volume 10 isn't 5 times as loud as volume 2, which makes the volume-mixing hard. Thanks for the replies anyway!
  10. Hi @SpiceWare, I'm trying to add a 4-bit PCM audio sound-effect to my game (writing AUDV0 on every scanline). I got something working in plain 6507 assembly, and now I'm trying to use the ARM to pre-calculate the amplitudes so I can simply read them from a data-stream and write to AUDV0 (instead of calculating them on the 6507 each scanline using a 16-bit cycle register and a 16-bit pitch/delta value). However it looks like (partially?) support for that is already in the example project that you shared (referring to methods like 'setNote' and 'setWaveform' in defines_cdsf.h). But I have no idea how to actually set a note from ARM and which predefined(?) datastream to read and store in AUDV0 from assembly code. Also, I was wondering how to keep writing to AUDV0 during the time the ARM is called on VerticalBlank and OverScan. I found this forum post by you, where you say that the 6507 is being fed NOPs during the duration of an ARM subroutine being called. That makes sense, as the 6507 must be doing something while one of the ARM functions is called. And later in that same forum discussion you mention a ZP routine that can run while the ARM is still running, using the 'ldx PosObject' instruction to check if the ARM has finished yet. Do you maybe have a simple example on how to play a single note using 4-bit PCM audio, using CDJF? Maybe you already explained this in one of your earlier posts on DPC+, but I couldn't find it using the forum's search. Cheers, Dion BTW: programming games using CDJF is an amazing experience! I like how it brings me new possibilities, while still I have to fight the limitations of the '2600. Just like my 6502 assembly code, my C code also has to be highly optimized. You can't get sloppy/lazy 🙂
  11. Hi @Thomas Jentzsch, I'm reviving an old thread, because I'm also trying to do frequency mixing, but I don't get the results I was hoping for. When mixing frequencies, I noticed some 'distortion' in the audio output, even when doing multiple updates per frame. In Star Castle I also do hear some distortion, but way less than during my own experiments. Maybe the distortion is more noticeable for the high pitch notes? Did you use some special tricks to get rid of the distortion when mixing frequencies? I've created a test rom that slowly changes the audio pitch/frequency by mixing frequencies. In the example settings, I'm using the clean waveform/tone (nr. 12), and then starting with frequency #14, gradually mixing in frequency #15 and after 2 seconds mixing back to frequency #14 again. I've added the rom and sources here, in case someone wants to have a look. For now I'm going to look at alternative solutions for slowly sliding frequencies. sliding-audio.zip
  12. Here you have scans for the stickers of Missile Control and Treasure Below (they were torn off a cartridge, so look a bit wrinkled)
  13. Note that for Atari 2600 Jr PAL Rev. F (similar to most '2600 Jr NTSC consoles), the modulator components are integrated on the board. So that's the reason for removing R17, which will basically stop interference from the modulator by disabling it.
  14. I've read several posts about people saying that no composite mod exists for the Atari 2600 Jr PAL Revision F. However, you just need to know which components you have to remove and how to connect a specific composite mod, which I'm showing in this post. For my mod, I've used the Deluxe Composite Video Mod Kit sold by thefuturewas8bit.com (and designed by Tynemouth Software). I like this mod, because it includes a 3.5mm jack socket which perfectly fits the Atari Jr, without the need to drill any holes in the console shell. Also, this mod gives me a crystal-clear composite output. Instructions [warning: these instructions are only applicable to the Atari 2600 Jr PAL Rev. F. For other revisions, please read the online instructions on thefuturewas8bit.com] After opening you Atari 2600 Jr PAL Rev F, you should remove the original RF plug, and then remove components Q4, L6, R17, C33, R48 and R56 (see below). Then solder the 4 wires of the composite mod (yellow, red, black and white) to these positions: Note that I actually soldered the wires to the back of the board, by pulling the 4 wires of the composite mod through the little hole left by removing L6. IMO that looks better. Then I placed the 3.5mm jack socket where the RF connector used to be, using the included double-sided tape to raise it a bit, and a small tie-wrap to keep the socket in place (note that the tie-wrap goes through the holes that were left by removing the RF connector) Then I mounted the inner shield back on: And finally used a black marker to color the double-sided tape black. Hope this helps!
  15. The boxes of the NTSC/US '2600 SEGA games use the "-01" serial numbers (so matching the serial numbers on the cartridge labels). So it appears that the "-10" numbers are used to indicate the PAL/EU versions of the box, but I think they forgot to also use these numbers on the cartridge labels. I guess the only way to determinate if a box-less '2600 SEGA game is PAL or NTSC, is by actually playing it and checking the colors 🙂 [NTSC/US box for Buck Rogers, showing "005-01"]
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