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Author Topic: whats the deal with OS9 and BW/16color modes?  (Read 1943 times)

goodoldmacs

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whats the deal with OS9 and BW/16color modes?
« on: May 18, 2024, 11:03:14 AM »

i have read conflicting information like you can enable the modes if you use particular monitors or if you replace the monitors extension with some specific older version, etc etc

it seems like one of those things though where the only reason programs wont run in higher color modes is just because the program itself is set to stop running?  like even if the system were in 256 or higher, the program would still run fine...if it wasn't closing itself down?

in all the years of mac tweaking is there no trick to either 1) get those modes available in OS9 or 2) trick the program into running anyway?
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joevt

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #1 on: May 19, 2024, 06:05:29 AM »

It has nothing to do with the display and everything to do with the hardware and driver.

SheepShaver's emulated graphics device supports all color depths and resolutions in Mac OS 9.0.4.

A program shouldn't depend on a color depth unless it's using its own drawing routines.

A game that's made for the original black and white Macs, on top of requiring a black and white mode, may also require a specific resolution (512x342) and even a specific framebuffer address.

I suppose you could make an emulated framebuffer in a newer Mac and copy that buffer to the real framebuffer at 60fps (or less if that takes too much processing power). Changing the framebuffer address is probably not possible (unless you can do something tricky with virtual memory?) - it may be easier to patch the program.
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goodoldmacs

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #2 on: May 21, 2024, 11:13:02 AM »

 maybe i should have been more specific:

there are a fair number of games made for OS7 that won't work in OS9 on a standard GeForce MX 20, because when you try to run them they say in an error, "please set to 16 colors mode and try again"...but in the monitors panel, there's no option.

so that was the problem i was trying to understand if there is some solution.

anyway your explanation makes sense, it's just...ok so a program requires black and white mode, a specific resolution, and a framebuffer address....why is that impossible to work around after 20+ years of OS9/OS10?

also there are some programs that run in 16 colors, lower resolution, yet you can use these on OS9.  they just run in a typical finder window in the middle of the screen.

i'm sure some programs do have advanced frame codes but isn't it also possible that some are just simply programmed to get the user to switch to 16 color mode not because it is technically required but just because...no real reason?  except maybe it caused the game to run better at the time it was released?
  like for example, classic 16 color sim city has this lock, but there is nothing so advanced or particular about its graphics.

so yes the point i was making is surely someone must have figured a workaround?  either an extension that adds a framebuffer emulation like you say, or maybe a method using resedit to simply remove the check?  after all, if it simply didnt have the check run at the beginning, then tried to run the game anyway, what's the worst that could happen?  a crash and restart?  at least then there would be a chance to play it.
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robespierre

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #3 on: May 21, 2024, 02:14:23 PM »

Graphics APIs are complicated and there are operations that are not fully generic for efficiency reasons.

Let's say there is a program that displays graphics using QuickDraw. It sets the pen color using the 16-color QuickDraw API, then calls QuickDraw commands to display text and circles and lines etc on the screen. This program will work fine when the monitor is set to 16 colors, 256 colors, thousands, or millions. Actually, it will even work fine in black and white, although some of the graphics may be harder to read.

Now suppose that a second program, just like the first, is designed with 16-color graphics in mind. But besides what the first program does, it does something more. It calls the QuickDraw function to grab the screen as a display buffer and then writes data to that array directly (not through the pen/pattern API). Now this program really only will work if the display is in 16-color mode and the screen array is in the packed 4 bit/pixel format it expects. In any other display depth or format, the assumptions it makes will be violated. If it checks for this situation it will exit with an error like "Please set your display to 16 colors and try again", but if it does not check, it will corrupt the display with garbage. Whether or not an error message is displayed, it cannot work because its assumptions have been violated.
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joevt

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #4 on: May 22, 2024, 12:45:12 AM »

Nothing is impossible if you through enough time / software / hardware at it.

Stepping Out II is a virtual framebuffer.
  https://www.macintoshrepository.org/40033-stepping-out-ii
Does it have B&W, 4 color, and 16 color modes? I think so. Can it add B&W, 4 color, and 16 color modes when the graphics controller is limited to 256 or more colors? I don't know. It may not be suitable for games because there's probably a terrific amount of overhead to copy 60 fps. Color translation on top of that would make it even worse.

I suppose an app could require a color mode for no real reason but it's unlikely. You're not going to get it to run unless you do as it says, or you patch the app.
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ssp3

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #5 on: May 22, 2024, 01:21:02 AM »

Have you tried:
* older Monitors control panel?
* Griffin SuperRes?
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IIO

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #6 on: May 22, 2024, 02:21:30 AM »

Have you tried:
* older Monitors control panel?
* Griffin SuperRes?

the core of the original question was "can you run OS9 in 16 color mode and if yes, how?"

it is an interesting question, but my personal experience with that goes to zero.

i have, however, tested about 300 OS9 extensions, and cant remember one for that kind of thing.
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goodoldmacs

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #7 on: May 24, 2024, 01:04:32 PM »


the core of the original question was "can you run OS9 in 16 color mode and if yes, how?"


thanks, that helpfully sums it up

also i would add:  and if a game has a check for a certain color mode at startup, how can you trick or remove that check?

like for example, sim city returns this error on an OS9 G4...yet is it reasonable that there's a real requirement?  and since there are no real consequences why not run it anyway and if it crashes, who cares, you just restart?

i will try to look for the extensions mentioned in this thread, and keep trying to use an earlier monitor panel (when i tried it before i just got an error opening the old panel, i forget the exact wording).
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IIO

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #8 on: May 25, 2024, 07:48:53 AM »

i am clueless when it comes to the truth, but i want to guess:

i think in times of 16 and 256 colors those numbers were absolute requirements already on the conjunction between a monitor and a PC.

and until today, if an app sets the colormode to 256 colors, that is a systemwide thing, which affects the OS and the GPU and also switches something in the monitor. what i want to say with that is that it is not just a value truncation (=downsampling) of the colors, it is a operational mode of your whole setup.

that still does not really explain why OS7 and higher do not offer a 16 color mode any more. or maybe they were absolutely sure that no hardware components will still support it?
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ssp3

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #9 on: May 25, 2024, 08:19:25 AM »

that still does not really explain why OS7 and higher do not offer a 16 color mode any more. or maybe they were absolutely sure that no hardware components will still support it?

For what it's worth, it is possible to set 16 colors when running 9.0.4 in emulation (Sheep Shaver).
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IIO

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #10 on: May 25, 2024, 12:49:40 PM »

aha. so the bad guy is the GPU or something later.
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joevt

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #11 on: May 25, 2024, 01:18:13 PM »

The Power Mac 6100 has a graphics controller that support B&W, 4 color, 16 color, 256 color, and Thousands of colors up to Mac OS 9.1.
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Jubadub

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #12 on: May 26, 2024, 12:54:35 AM »

The Power Mac 6100 has a graphics controller that support B&W, 4 color, 16 color, 256 color, and Thousands of colors up to Mac OS 9.1.

Is that controller a PCI module? I think I had one of those, with 2 MB VRAM, which I had obtained specifically for the purpose of trying out less-than-256 colors on my MDD under Mac OS 9.2.2. (Unfortunately a lot happened and it got stolen from me before I could even test it.)
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ssp3

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #13 on: May 26, 2024, 01:14:27 AM »

PM 6100 is a NuBus machine. No PCI in sight  ;)
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IIO

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #14 on: May 26, 2024, 01:18:29 AM »

2mb VRAM, upgradeable to 4, was what the 7300 / 8600 had onboard - the last machines which shipped without dedicated GPU when i am not wrong.

can´t remember a 16 colormode there, but definetly b/w. (but was that b/w really b/w or actually greyscaled 8-bit?)
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joevt

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Re: whats the deal with OS9 and BW/16color modes?
« Reply #15 on: May 26, 2024, 04:03:01 AM »

2mb VRAM, upgradeable to 4, was what the 7300 / 8600 had onboard - the last machines which shipped without dedicated GPU when i am not wrong.

can´t remember a 16 colormode there, but definetly b/w. (but was that b/w really b/w or actually greyscaled 8-bit?)
256 color was the minimum color depth on the PCI Macs.

Modes that are less than Thousands of colors use a color palette to choose the colors so all of those modes have a gray scale option.
4 colors, 4 grays, 16 colors, 16 grays, 256 colors, 256 grays.
A gamma table may be applied to the colors in the color palette.

For thousands and millions of colors, the color palette may be used for the gamma table but DingusPPC ignores the color palette in these modes which is why you might see a difference in colors for an emulated machine with two displays where one of the displays is using index color (≤ 256 colors) and the other display is using direct color (≥ Thousands of colors).

The Power Mac 6100 AV models have a separate graphics controller for a second display. DingusPPC doesn't emulate that. The AV model's extra display output allows up to millions of colors.
« Last Edit: May 26, 2024, 04:18:19 AM by joevt »
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