Kr0tki Posted May 13, 2009 Author Share Posted May 13, 2009 You're right, the algorithm would work without changes. However the 16 luminance values are based on voltage data from the CGIA.PDF document, so they don't necessarily apply to other consoles. (Although I suspect that TIA and MARIA generate lumiance signal the same way that GTIA does, so maybe it could be left unchanged.) If similar voltage data for TIA or MARIA is available, then it should be used instead. Alternatively, you may forget the whole issue and just compute lumas linearly, sacrificing a little accuracy. Quote Link to comment Share on other sites More sharing options...
Shannon Posted May 13, 2009 Share Posted May 13, 2009 Nice work! Let us know when you have code useable in A800... Or is the current code easily pluggable? If so I can plug it in to use the "normal" values you had listed in the readme. Then I'll add a menu where the user can "adjust" those values as preferred. Well, there might be some work involved if one wanted to integrate it with the existing code that computes palette in the "NTSC filter" mode (as mentioned above). It would be nice if the same color genertation was used in the "NTSC filter" mode and the normal mode; alas Atari800 isn't working that way right now. No biggy I don't have the NTSC filter stuff implemented anyways. Is it anygood? Quote Link to comment Share on other sites More sharing options...
Kr0tki Posted May 14, 2009 Author Share Posted May 14, 2009 Any good? You don't know what you miss till you try it. Go and download the SDL version. It is THE way of emulating artifacting. Its a huge feature, even for the Xbox version. Quote Link to comment Share on other sites More sharing options...
Shannon Posted May 14, 2009 Share Posted May 14, 2009 Was it part of the 2.03 core? I remember there being some type of experimental alternative artifacting code but I didn't really care for the results. Quote Link to comment Share on other sites More sharing options...
Kr0tki Posted May 15, 2009 Author Share Posted May 15, 2009 Yes, it's the thing. Although it is fully stable now, and shouldn't be considered experimental - it even is switchable from GUI now. Quote Link to comment Share on other sites More sharing options...
Shannon Posted August 3, 2009 Share Posted August 3, 2009 Was looking at the NTSC code today and realized it was part of the SDL code which the xbox version does not really work off of. Is it hard to get it working on other platforms? I don't really understand filters that much. Quote Link to comment Share on other sites More sharing options...
Shannon Posted August 12, 2009 Share Posted August 12, 2009 ok. Well I have to say now that "I'm a believer!". I finally got it working in atarixlbox and am really impressed with it. Especially the way artifacting is reproduced!! Nice to see games like Lode Runner, Jawbreaker, AE in their full "artifacting" glory!! I used to always wonder why any one would want to "recreate" old imperfect NTSC style images. Why go backwards? When the image is so sharp now! But after playing through a few titles I could just feel the old nostalgia feeling kicking back in!! It really is worth it to try it out. It may not be the greatest thing for all games but it really does a good job and still keeps the image clean enough to not hamper the enjoyment! Quote Link to comment Share on other sites More sharing options...
ColecoFan1981 Posted October 12, 2009 Share Posted October 12, 2009 (edited) The last thing I'd like to know is how to properly convert hue phase angles into radians, as given by this particular formula: theta = pi * ((cols(z) + hue) / 180) For instance: if I was to plug in a color to this formula which is in column 1, and with a hue of 210 (would this be 1 + 210 = 211?), what would the theta be? I tried it out and this did not give me a consistent result: the theta value returned was 3.6826 radians, which I don't believe is correct. Please help me. But even if 3.6826 radians is correct, I don't believe this part of the equation will be enough to give me a consistent result as to the correct hue to plug into the next formula: R = Y + S * SIN(theta) G = Y - 0.5094 * S * SIN(theta) - 0.1887 * S * COS(theta) B = Y + S * COS(theta) Thank you, Ben Edited October 12, 2009 by ColecoFan1981 Quote Link to comment Share on other sites More sharing options...
Kr0tki Posted October 12, 2009 Author Share Posted October 12, 2009 (edited) The last thing I'd like to know is how to properly convert hue phase angles into radians, as given by this particular formula: theta = pi * ((cols(z) + hue) / 180) I don't quite understand what you mean. Where is this formula coming from? What are cols, z, hue intended to mean? Are you asking how to convert between degrees and radians? For instance: if I was to plug in a color to this formula which is in column 1, and with a hue of 210 (would this be 1 + 210 = 211?), what would the theta be? I tried it out and this did not give me a consistent result: the theta value returned was 3.6826 radians, which I don't believe is correct. Please help me. What do you mean, the result was inconsistent? Was it changing between repeated uses of the formula? But even if 3.6826 radians is correct, I don't believe this part of the equation will be enough to give me a consistent result as to the correct hue to plug into the next formula: R = Y + S * SIN(theta) G = Y - 0.5094 * S * SIN(theta) - 0.1887 * S * COS(theta) B = Y + S * COS(theta) I don't know this formula, either. However if you're trying to devise an algorithm that produces RGB values of Atari colours, I suggest you to look into the palgen-ntsc source that was posted in this thread earlier. Edited October 12, 2009 by Kr0tki Quote Link to comment Share on other sites More sharing options...
Rybags Posted October 12, 2009 Share Posted October 12, 2009 (edited) 2 * Pi is a complete circle in Radians, so 3.6826 radians is a touch under 211 Degrees. Edited October 12, 2009 by Rybags Quote Link to comment Share on other sites More sharing options...
Kr0tki Posted November 26, 2009 Author Share Posted November 26, 2009 (edited) I'm proud to announce that the palette adjustments devised in this thread have been integrated into the source of Atari800, thus it becoming the first emulator with exact emulation of colours Thanks to all for help. Edited November 26, 2009 by Kr0tki Quote Link to comment Share on other sites More sharing options...
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