 No.22563
Robbbert Moderator
Dec 8, 2024, 21:27
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Could be because of resistors. |
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 No.22565
125scratch Tester
Dec 8, 2024, 22:59
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How so? |
 No.22566
hap Developer
Dec 8, 2024, 23:23
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Like this (yiear.cpp in this example) Then yes, max blue will have slightly lower voltage than max red or green. bit 7 -- 220 ohm resistor -- BLUE -- 470 ohm resistor -- BLUE -- 220 ohm resistor -- GREEN -- 470 ohm resistor -- GREEN -- 1 kohm resistor -- GREEN -- 220 ohm resistor -- RED -- 470 ohm resistor -- RED bit 0 -- 1 kohm resistor -- RED |
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No.22567
125scratch Tester
Dec 8, 2024, 23:35
edited on: Dec 8, 2024, 23:42
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I suppose that makes some amount of sense, but I'm wondering why drivers like pacman and mappy used to be like this but aren't anymore. I always thought it was a bit of an inconsistency, and felt like since Galaga hardware is similar, it should also have higher blue values in most cases, and Galaga and Dig Dug cabinets I've played don't seem to have that issue, though I know analog video and CRTs are a factor. |
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No.22568
hap Developer
Dec 8, 2024, 23:41
edited on: Dec 9, 2024, 00:00
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pacman (I mean, the pacman.cpp driver) uses resnet.h, maybe more accurate that way? |
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No.22569
125scratch Tester
Dec 8, 2024, 23:45
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I realize I haven't provided any real hardware examples, I did look for some but found them hard to find, and analog video is somewhat inconsistent anyway. |
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No.22687
125scratch Tester
Dec 23, 2024, 22:20
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I wonder if it would technically be more accurate to use the galaxian color system, since I noticed its colors are darker, and the blue is slightly lower but not to the same extent. It could be too dark, but it's something to think about. |
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No.24329
125scratch Tester
1 day ago
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Noticed hap has been making some "normalize blue palette" changes to some sources like snk6502.cpp and jack.cpp. I wonder if these could also be applied to galaga.cpp, rallyx.cpp, and other sets. (As for galaga.cpp, I'm not really sure how Xevious handles color but it seems to have a larger palette than other galaga.cpp games so maybe it could be handled differently) |
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No.24330
125scratch Tester
1 day ago
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meant "other sources", not sets |
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No.24335
hap Developer
11 hours ago
edited on: 11 hours ago
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galaga white will become blu-ish if I normalize blue. The same thing happens if I emulate the palette with a resnet (which matches schematics, nothing complex about it). I can do that commit later today, but I'm not 100% sure the lightblue white correct, or if it's just a case of increased contrast on the display (contrast of 1.15 = white). Similarly, I'm also not sure if mappy or pacman's white is supposed to be lightblue either. |
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No.24336
125scratch Tester
10 hours ago
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Yeah, that's fair. I personally always thought the higher blue levels were intended for galaga, but maybe there's something about the original hardware that makes the whites less bluish. I still think the normalized blue looks more "correct", mostly because it's consistent with other 8x8x4 RGB palettes, and also because to me the blues on real hardware look brighter, for example the sky in Dig Dug. Could be CRT stuff though, but I'm not sure. |
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No.24337
hap Developer
8 hours ago
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resnet added here for galaga,bosco,digdug: https://github.com/mamedev/mame/commit/84ffd54c16f670524918ee4d96d283d1a9012962 rallyx was already correct, it has a 1k pulldown on blue (double checked with schematics) |
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No.24338
125scratch Tester
5 hours ago
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Huh, that makes me wonder if the normalized blue on galaga is correct then. It might not be, but it's your call. |
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No.24339
hap Developer
4 hours ago
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All I can say is it matches schematics, and also matches MAME's pacman/mappy emulation (they also have lighblue white). It's not easy to determine if it's correct by looking at PCB videos just from a single color, since it depends too much on monitor knobs (contrast, brightness, ..) |