Genesis color counts, myths shattered?
Scott H
update' thread I was further educated as to the shadow and lighting
techniques of the Genesis hardware and how this was used to simulate
more colors on screen, or for other purposes. As a result, I have
completed a short comparison page showing a screenshot of a Demo
demonstrating the Genesis displaying 256 colors simultaneously in a
non-game environment. Then there are screenshots of Sonic 2 in
"nightmode" which is using the shadow effect, and Castlevania Bloodlines
doing the same in normal gameplay. Sonic 2's nightmode is the only game
so far that I've seen actually hit the 61 (non-transparent) colors on
screen limit, while Bloodlines is still displaying 54 on screen like
most Genesis games.
Also, since it's been unanimously accepted that Eternal Champions
Challenge from the Darkside was the first and only 256 color Sega CD
game, I decided to take emulation shots of it in action, and have Gif
movie gear tell me the actual colors being output. Not surprisingly, it
too is only displaying 54 colors on screen and in FMV, and the blurring
from the A/V out was used to cover up the extensive artistic usage of
dithering and other techniques for color transitions. So, as it stands,
no Genesis or Sega CD game actually outputs (technically) more than 64
colors on screen, but many use effects and the blurring of the output to
cause the illusion of more colors being displayed at once.
http://www.gamepilgrimage.com/TheSegaGenesis.htm
Lighting effects:
http://www.gamepilgrimage.com/GENlighting.htm
Eternal Champions:
http://www.gamepilgrimage.com/EC-CFTDS.htm
--
Scott
LocalH
look at the screenshot you've got when you're checking the number of
colors, and you'll see that the color gradations are a lot less smooth
in that "253" color shot than they are in the fullscreen shot. But there
are definitely 1536 colors in that demo (the 512 hardware colors
multiplied by three - shadow, normal, hilight - gives 1536).
As for Eternal Champions CD, I haven't checked it, so I don't know how
much of the "256 colors" was dithering (although on a stock Genesis with
RF or composite output, that dithering works beautifully).
TapamN
> So, as it stands,
> no Genesis or Sega CD game actually outputs (technically) more than 64
> colors on screen, but many use effects and the blurring of the output to
> cause the illusion of more colors being displayed at once.
The Traveller's Tales logo on Sonic 3D Blast has 100 colors.
BelPowerslave
That game...well, let me say "what happens before it starts" is pretty
advanced. ;) Has the full motion video intro and everything. Sadly, the
actual game doesn't look nearly as what happens before it. :( (though the
Saturn version is great)
More than anything, I'd be interested in this rumor that Toy Story is using
more than 64 on screen colors. I read that in a GameFan...and doing my quick
review on the game, I don't remember any screenshot using more than 64...
Bel
--
Whip Ass Gaming: http://www.whipassgaming.com/
"Did you just meow?"
- Me
Scott H
Hmm, if it had stated 256 I'd have supposed Gif Movie Gear had trimmed
it down and looked more closely. You're right, there are way more color
gradients in the original screenshot. I'll change that.
> As for Eternal Champions CD, I haven't checked it, so I don't know how
> much of the "256 colors" was dithering (although on a stock Genesis with
> RF or composite output, that dithering works beautifully).
Well, according to the GENS .BMP pics and Gif Movie Gear, it's not over
the normal limit of 55 or so.
--
Scott
Scott H
Cool, I'll try to check that out tomorrow or Monday to see.
Thanks,
--
Scott
Scott H
> LocalH wrote:
>
>> As for Eternal Champions CD, I haven't checked it, so I don't know how
>> much of the "256 colors" was dithering (although on a stock Genesis
>> with RF or composite output, that dithering works beautifully).
>
>
> Well, according to the GENS .BMP pics and Gif Movie Gear, it's not over
> the normal limit of 55 or so.
>
>
But you're right, with A/V or RF it looks great, and I've tried to
demonstrate that with the comparison page for EC-CD.
--
Scott
Scott H
> http://www.gamepilgrimage.com/TheSegaGenesis.htm
>
> Lighting effects:
> http://www.gamepilgrimage.com/GENlighting.htm
>
> Eternal Champions:
> http://www.gamepilgrimage.com/EC-CFTDS.htm
>
>
I should clarify a bit. Exciting thread title aside, the Genesis'
shadow technique does effectively, technically, double the colors on
screen with each time the effect is used. The reason I think my
software doesn't recognize this is because it is effectively only making
a darker version of the lighter color, and it's not different enough for
the software to recognize it. I think this effect was also used in some
of the 3D effects in Gunstar Heroes to make the various sides of things
look shaded on one end. So, while the effect is visually creating new
colors, they aren't radically different like comparable Snes games, and
the effect does little for the gradients between colors, but merely
increases perceivable the on screen color count. I'd like to find out
what Sonic & Knuckle's color trick was, because I remember statements of
it doing more colors than the Genesis was capable of, but I think it
was in the color palette, not the on screen colors.
--
Scott
LocalH
mid-frame. This is how the Sonic games do water, they keep track of the
current on-screen water position, and place sprites over the area where
the pallet is changed. The sprites help hide any possible "garbage" that
results from writing to CRAM during the visible screen, and also any
garbage resulting from not being able to change all 16 colors in one
line. You can't change all 16 colors of a pallet line during vblank, but
you can modify several colors (a friend of mine made code that used DMA
and was able to change 8 colors during one hblank period, so it should
only take two scanlines to fully change a 16-color pallet).
It's also possible to change the backdrop at any arbitrary point on the
screen, even right smack dab in the middle of a scanline. Many games use
this for simple gradients in the background (a good example is Shadow of
the Beast). I've written proof-of-concept code that did 18 "raster
splits" (where the backdrop was changed mid-line), but due to various
issues the splits jittered. I could probably do more if I used CPU
registers instead of memory to store the values, but I digress.
There are definitely ways of making a machine display more than the
"official" color limit - this really applies to quite a few systems (for
example, the Commodore 64 can display 16 hardware colors, and at a
160x200 resolution is can display 3 colors plus background in a 4x8
character bitmap (two bits per pixel). However, very ingenious coders
have blown that "limit" completely away - through techniques such as
interlacing and sprite overlay, I've seen images with upwards of 90
apparent colors at an apparent resolution of 320x200.
Scott H
Hmm, so the water in Sonic 1 isn't using a varient of this shadow
technique? It's odd that two different palettes can be displayed on
screen while Gif Movie Gear still only detects about 45 colors. I
mean, the level design might simply be limited to half the colors per
palette, but it isn't noticably so. Aquatic Ruins in Sonic 2 shows up
as 75 colors though, that's the first time I've seen a Genesis pic go
over 61 colors. That at least demonstrates the changed color palette.
If that could be used in a game like Sonic 2 (especially with the amount
of apparent parallax in that level), then it's more fair to say that the
Genesis color limitation is more of a limit per sprite or background
(like it was on the TG16), rather than an absolute on screen limitation.
In other words, that it's only limited in the sense that color
gradients on a single object would be less than that of the Snes. Which
brings the question of how many Snes games didn't use the mode with 16
color sprites, and how they overcame the background limitation of that
higher sprite color mode.
> It's also possible to change the backdrop at any arbitrary point on the
> screen, even right smack dab in the middle of a scanline. Many games use
> this for simple gradients in the background (a good example is Shadow of
> the Beast). I've written proof-of-concept code that did 18 "raster
> splits" (where the backdrop was changed mid-line), but due to various
> issues the splits jittered. I could probably do more if I used CPU
> registers instead of memory to store the values, but I digress.
>
> There are definitely ways of making a machine display more than the
> "official" color limit - this really applies to quite a few systems (for
> example, the Commodore 64 can display 16 hardware colors, and at a
> 160x200 resolution is can display 3 colors plus background in a 4x8
> character bitmap (two bits per pixel). However, very ingenious coders
> have blown that "limit" completely away - through techniques such as
> interlacing and sprite overlay, I've seen images with upwards of 90
> apparent colors at an apparent resolution of 320x200.
I'd be very interested to see things like this in action. I can't
really picture what it would look like.
--
Scott
LocalH
> Hmm, so the water in Sonic 1 isn't using a varient of this shadow
> technique? It's odd that two different palettes can be displayed on
> screen while Gif Movie Gear still only detects about 45 colors. I
> mean, the level design might simply be limited to half the colors per
> palette, but it isn't noticably so. Aquatic Ruins in Sonic 2 shows up
> as 75 colors though, that's the first time I've seen a Genesis pic go
> over 61 colors. That at least demonstrates the changed color palette.
> If that could be used in a game like Sonic 2 (especially with the amount
> of apparent parallax in that level), then it's more fair to say that the
> Genesis color limitation is more of a limit per sprite or background
> (like it was on the TG16), rather than an absolute on screen limitation.
> In other words, that it's only limited in the sense that color
> gradients on a single object would be less than that of the Snes. Which
> brings the question of how many Snes games didn't use the mode with 16
> color sprites, and how they overcame the background limitation of that
> higher sprite color mode.
>
lines for a total of 64 colors as the hardware "limit", so that's why
you hear people saying that the Genesis can display 64 colors "max". The
Genesis can choose from 512 base colors (8 bits per color component, and
8*8*8=512). So yeah, the only real limits are 16 colors per tile, which
can be any of four pallet lines, so you can only have 64 "base" colors
at any one time. The techniques to increase the colors are just
basically changing those colors mid-frame and using shadow/highlight to
get extra colors.
Theoretically, you could have a "screen mode" on the Genesis similar to
that of the Amiga's "Dynamic Hires" mode, which changed all 16 pallet
entries every scanline - the Genesis can't quite do this, but you could
change 8 of the colors each line, so you could change the first 8 colors
on even scanlines and the second 8 on odd scanlines. You could probably
also use other graphics on-screen at the same time (sprites or the other
scroll layer), but they'd have to stay away from the pallet that you're
changing every line.
>
>> It's also possible to change the backdrop at any arbitrary point on
>> the screen, even right smack dab in the middle of a scanline. Many
>> games use this for simple gradients in the background (a good example
>> is Shadow of the Beast). I've written proof-of-concept code that did
>> 18 "raster splits" (where the backdrop was changed mid-line), but due
>> to various issues the splits jittered. I could probably do more if I
>> used CPU registers instead of memory to store the values, but I digress.
>>
>> There are definitely ways of making a machine display more than the
>> "official" color limit - this really applies to quite a few systems
>> (for example, the Commodore 64 can display 16 hardware colors, and at
>> a 160x200 resolution is can display 3 colors plus background in a 4x8
>> character bitmap (two bits per pixel). However, very ingenious coders
>> have blown that "limit" completely away - through techniques such as
>> interlacing and sprite overlay, I've seen images with upwards of 90
>> apparent colors at an apparent resolution of 320x200.
>
> I'd be very interested to see things like this in action. I can't
> really picture what it would look like.
>
Well, I lost my work on the raster splits in a hard drive semi-failure
(the drive still spins up, but it's bad enough where I can't boot from
it, but I think I could salvage some of the data). Also, just in case I
wasn't quite so clear, the 90-color thing I mention was of course on the
C64. You can see a lot of the C64 stuff at http://www.demodungeon.com,
it can be quite amazing.
LocalH
> Well, you have a maximum of 16 colors per pallet line, and four pallet
> lines for a total of 64 colors as the hardware "limit", so that's why
> you hear people saying that the Genesis can display 64 colors "max". The
> Genesis can choose from 512 base colors (8 bits per color component, and
> 8*8*8=512). So yeah, the only real limits are 16 colors per tile, which
> can be any of four pallet lines, so you can only have 64 "base" colors
> at any one time. The techniques to increase the colors are just
> basically changing those colors mid-frame and using shadow/highlight to
> get extra colors.
>
3bpp, essentially, and not 8bpp. In memory, the colors are stored in hex
as $0BGR, with the low bit of each component being unused (normally kept
as 0).
Scott H
I've noticed that some games look more crisp than others as well.
The Sonic games have a much better overall look than stuff like Bubsy,
and the Street Fighter games have a strange kind of shimmer on edges
that shows up in screenshots, that's not in other native titles like
SOR2. Some games look blurrier still than the output alone should
provide. Then there's EA's games, as much as people like to praise them
during this era, why they insisted on using their own engines which
limited the games to what looks like 16 colors ON SCREEN, is beyond me.
That, and ports like the MK games using dithering in the backgrounds
instead of just making the backgrounds up of more sprites really bugs
me. Actually, dithering bothers me in general, I can usually notice it
even with the blurred output and much prefer a simple image that doesn't
expose the limits of the colors.
> Theoretically, you could have a "screen mode" on the Genesis similar to
> that of the Amiga's "Dynamic Hires" mode, which changed all 16 pallet
> entries every scanline - the Genesis can't quite do this, but you could
> change 8 of the colors each line, so you could change the first 8 colors
> on even scanlines and the second 8 on odd scanlines. You could probably
> also use other graphics on-screen at the same time (sprites or the other
> scroll layer), but they'd have to stay away from the pallet that you're
> changing every line.
I wonder if something like this might have been used in cutscenes in
some games. Wouldn't the palette swap mid frame result in a shimmering,
rather than a solid color?
>>
>> I'd be very interested to see things like this in action. I can't
>> really picture what it would look like.
>>
> Well, I lost my work on the raster splits in a hard drive semi-failure
> (the drive still spins up, but it's bad enough where I can't boot from
> it, but I think I could salvage some of the data). Also, just in case I
> wasn't quite so clear, the 90-color thing I mention was of course on the
> C64. You can see a lot of the C64 stuff at http://www.demodungeon.com,
> it can be quite amazing.
Some of the low color animations turned out amazing! Shows what
artistic ability can do with "limited" colors.
--
Scott
LocalH
>> Theoretically, you could have a "screen mode" on the Genesis similar
>> to that of the Amiga's "Dynamic Hires" mode, which changed all 16
>> pallet entries every scanline - the Genesis can't quite do this, but
>> you could change 8 of the colors each line, so you could change the
>> first 8 colors on even scanlines and the second 8 on odd scanlines.
>> You could probably also use other graphics on-screen at the same time
>> (sprites or the other scroll layer), but they'd have to stay away from
>> the pallet that you're changing every line.
>
> I wonder if something like this might have been used in cutscenes in
> some games. Wouldn't the palette swap mid frame result in a shimmering,
> rather than a solid color?
>
won't cause shimmering, as long as you change the pallet in the hblank.
As long as you use the same colors on the same scanlines consistently on
each frame, then you should have a rock solid image.
Scott H
I'm still trying to picture the results. Would the intended use be to
create a color not present in the palette? I can't picture how this
technique would result in objects with more colors in them at once.
--
Scott