OS wide gamma correction.

[Thorham]

Having an old SVGA monitor for my Amiga that's a little on the dark side due to usage (phosphor wear), I thought it might be a good idea to implement system wide gamma correction.

Seems to me a good way would be to patch all the RGB setting functions in the graphics library.

Would it be safe to just turn off task switching and interrupts, alter the graphics library jump table, and then turn everything back on? Somehow it seems a little dirty...

[meynaf]

You can use exec.library's SetFunction() call. It will do all the work for you.

This will not bring you far however. Only programs that use the OS for display will be fine (oh, well, ok, this includes mine ).
Also be aware that gamma correction will reduce the r,g,b value precision and this might cause more damage than benefit. And it can't, of course, go beyond the maximum possible lightness so if your monitor has "too dark" image for all colors then this won't be fixed.

Perhaps just switching to another monitor would be a better solution

[Thorham]

Originally Posted by meynaf

You can use exec.library's SetFunction() call. It will do all the work for you.

That sounds much better than dirty hacks, thanks

Originally Posted by meynaf

This will not bring you far however. Only programs that use the OS for display will be fine

That's what it's for. I only really use OS friendly software anyway.

Originally Posted by meynaf

oh, well, ok, this includes mine

Indeed, nice for Dungeon Master.

Originally Posted by meynaf

Also be aware that gamma correction will reduce the r,g,b value precision and this might cause more damage than benefit.

It's worth trying, seeing how simple it is to do (or it should be ).

Originally Posted by meynaf

And it can't, of course, go beyond the maximum possible lightness so if your monitor has "too dark" image for all colors then this won't be fixed.

Too dark is a bad description. The monitor's gamma curve is wrong due to phosphor wear. Dark colors are too dark, very light colors like maximum white are fine. I use it with a monitor switcher on my peecee as well, and the video card driver's gamma correction works great.

Originally Posted by meynaf

Perhaps just switching to another monitor would be a better solution

Indeed, but I don't want to carry a heavy CRT around. Maybe I should just call a cab or something if I can find a CRT locally.

[meynaf]

Originally Posted by Thorham

That's what it's for. I only really use OS friendly software anyway.

No whdload games ?
No custom copperlists on screen ?

Originally Posted by Thorham

It's worth trying, seeing how simple it is to do (or it should be ).

I see no reason why it shouldn't work.
Oh, wait.
Anyone using a HAM screen will get garbage because only fixed pixels will be altered...

Well, for the sake of curiosity, it's probably worth trying anyway.

Originally Posted by Thorham

Too dark is a bad description. The monitor's gamma curve is wrong due to phosphor wear. Dark colors are too dark, very light colors like maximum white are fine. I use it with a monitor switcher on my peecee as well, and the video card driver's gamma correction works great.

And even playing with contrast/lightness doesn't help ?

Originally Posted by Thorham

Indeed, but I don't want to carry a heavy CRT around. Maybe I should just call a cab or something if I can find a CRT locally.

Yikes ! CRT

Perhaps you can go to your local Stan's Previously Owned LCD Monitor shop

[Thorham]

Originally Posted by meynaf

No whdload games ?

Haven't seriously played any in years because I need a good joystick. I have a video box for that anyway, and that has brightness controls (gamma would be better).

Originally Posted by meynaf

No custom copperlists on screen ?

Under the Os? What for?

Originally Posted by meynaf

Anyone using a HAM screen will get garbage because only fixed pixels will be altered...

Can probably be handled somehow (turn off gamma correction on HAM screens).

Originally Posted by meynaf

And even playing with contrast/lightness doesn't help ?

Absolutely not. The problem is the gamma curve, not contrast or brightness, that's why it doesn't work. Only gamma correction gives good results.

Originally Posted by meynaf

Yikes ! CRT

You used to like them and dislike LCDs, what happened?

Originally Posted by meynaf

Perhaps you can go to your local Stan's Previously Owned LCD Monitor shop

No way. I don't like crappy up scaling. CRTs are great for Amigas. Until flat panels can upscale at CRT quality levels, I'll stick to CRTs for as long as possible (not as my main peecee monitor, of course ).

[meynaf]

Originally Posted by Thorham

Under the Os? What for?

AGA sliced HAM ?

Originally Posted by Thorham

You used to like them and dislike LCDs, what happened?

Good old CBM monitors are still OK. But they're wearing off and have become near to impossible to repair (no spare parts available, no repairmen wanting to do it).

Current LCD screens seem to have a better image than a decade ago.
So they have become quite bearable.

Originally Posted by Thorham

No way. I don't like crappy up scaling. CRTs are great for Amigas. Until flat panels can upscale at CRT quality levels, I'll stick to CRTs for as long as possible (not as my main peecee monitor, of course ).

I've heard some LCD might have a good enough scaling.
In addition it might be less problematic for 31khz modes.
However you never know before trying...

[Thorham]

Originally Posted by meynaf

AGA sliced HAM ?

Good one.

Originally Posted by meynaf

Good old CBM monitors are still OK. But they're wearing off and have become near to impossible to repair (no spare parts available, no repairmen wanting to do it).

I can't say I miss those after using an SVGA monitor for years. Too small and no double scan.

Originally Posted by meynaf

Current LCD screens seem to have a better image than a decade ago.
So they have become quite bearable.

Yeah, I have a spare from 2005 that I got for free. It ain't pretty.

Originally Posted by meynaf

I've heard some LCD might have a good enough scaling.
In addition it might be less problematic for 31khz modes.
However you never know before trying...

The problem is indeed the trying.

[meynaf]

Originally Posted by Thorham

I can't say I miss those after using an SVGA monitor for years. Too small and no double scan.

SVGA usually can't sync to 15khz.
For old monitors, I miss the integrated loudspeakers - but now that's about all.

Originally Posted by Thorham

Yeah, I have a spare from 2005 that I got for free. It ain't pretty.

When i got my laptop i was surprised about the great image quality.

But perhaps next one will have an OLED display


Btw. For your gamma project, you can patch graphics.library's LoadRGB4(), LoadRGB32() and similar functions.
For custom screens that may be enough, but for the WB itself you may run into trouble. Apps must use the unmodified value for color matching, not the new one.

[Thorham]

Originally Posted by meynaf

SVGA usually can't sync to 15khz.

Mine certainly can't, and it's not a problem. I usually only use OS friendly software anyway.

Originally Posted by meynaf

For old monitors, I miss the integrated loudspeakers - but now that's about all.

You miss crappy built-in speakers? Once you use a proper amplifier with some half decent headphones, that will surely change, because the quality is sooooooo much better. Different universe kind of better.

Originally Posted by meynaf

When i got my laptop i was surprised about the great image quality.

Yeah, flat panels have become very good. I have a cheap 150 Euro one from five years ago, and it's already not bad (does have a shitty viewing angle).

Originally Posted by meynaf

For your gamma project, you can patch graphics.library's LoadRGB4(), LoadRGB32() and similar functions.

That's what I was thinking about. I was also thinking about using an invalid color index as a mode setting to allow setting the gamma value. Set the index to -1, and for the 32bit functions you can use red for the gamma value. For the 4bit functions use all channels. Should work well, because when you call these functions with an invalid color index, nothing happens (documented).

Originally Posted by meynaf

For custom screens that may be enough, but for the WB itself you may run into trouble. Apps must use the unmodified value for color matching, not the new one.

Perhaps, but I'm not expecting much trouble to be honest, although I wonder what will happen with PeterK's icon library

[meynaf]

Originally Posted by Thorham

You miss crappy built-in speakers? Once you use a proper amplifier with some half decent headphones, that will surely change, because the quality is sooooooo much better. Different universe kind of better.

Not the crappy ones, no
On some monitors (like 1084, 1085) they're crappy.
Not on others (like 1083).

A good monitor doesn't value a hi-fi system but it's certainly better than the small beepers of headphones, which eat all the bass.

Of course the worse is integrated loudspeakers in laptops

Originally Posted by Thorham

That's what I was thinking about. I was also thinking about using an invalid color index as a mode setting to allow setting the gamma value. Set the index to -1, and for the 32bit functions you can use red for the gamma value. For the 4bit functions use all channels. Should work well, because when you call these functions with an invalid color index, nothing happens (documented).

Doc says : "if the color value is unused then nothing will happen".
Sounds unclear to me. It doesn't say you're allowed to call the function with wildly out-of-range values.

[Thorham]

Originally Posted by meynaf

A good monitor doesn't value a hi-fi system but it's certainly better than the small beepers of headphones, which eat all the bass.

You clearly haven't heard even half decent headphones. If the headphones you've heard have less bass than the speakers of that 1083, then you've heard some absolutely worthless headphones.

Good headphones have good representations of all the audible frequencies, and cheap monitor speakers can't ever mach that. Only good loudspeakers do better. Not to mention that those weak, crappy little built-in amplifiers can't ever match a decent, dedicated stereo amplifier.

I actually have some powerful loudspeakers (old Kef Cadenza's), but they quickly become too loud, and I have neighbors. The headphones I have, have decent bass, so I use them. I was actually pleasantly surprised at how good those 45 Euro Sennheiser's are (not just bass, everything). I suspect that when you shell out around 250 Euros for a decent brand, you'll be blown away completely.

Originally Posted by meynaf

Doc says : "if the color value is unused then nothing will happen".
Sounds unclear to me. It doesn't say you're allowed to call the function with wildly out-of-range values.

It implies that it's alright to filter out negative index values. Basically, the patched functions detect that the index is -1, they set the gamma, and just exit without calling the original function. That way nothing happens.

[meynaf]

Originally Posted by Thorham

You clearly haven't heard even half decent headphones. If the headphones you've heard have less bass than the speakers of that 1083, then you've heard some absolutely worthless headphones.

How can you be sure of that, not having heard the 1083 ?
Where is your knowledge about how monitors sound is ?

I know how good headphones can sound. They damage the bass, even if of course you still hear them. They raise high frequencies.

Originally Posted by Thorham

Good headphones have good representations of all the audible frequencies, and cheap monitor speakers can't ever mach that. Only good loudspeakers do better. Not to mention that those weak, crappy little built-in amplifiers can't ever match a decent, dedicated stereo amplifier.

The amp can't beat a dedicated one maybe, but who cares. The signal is destroyed at the headphones level.

Even the most basic acoustic knowledge is against you. The monitor makes a quite nice subwoofer, especially in comparison to these ridiculously small headphones.

Only poor amp can be responsible of poor sound - and on this model it's quite okay (I know, I got a 1085 and, believe me, this one's near useless for playing sounds !).

Originally Posted by Thorham

I actually have some powerful loudspeakers (old Kef Cadenza's), but they quickly become too loud, and I have neighbors. The headphones I have, have decent bass, so I use them. I was actually pleasantly surprised at how good those 45 Euro Sennheiser's are (not just bass, everything). I suspect that when you shell out around 250 Euros for a decent brand, you'll be blown away completely.

It's just my money that would be blown away. 250 euros for just headphones ?
For that price i can get a whole stereo system !

Originally Posted by Thorham

It implies that it's alright to filter out negative index values. Basically, the patched functions detect that the index is -1, they set the gamma, and just exit without calling the original function. That way nothing happens.

The point isn't that. The trick is that you can't be sure that calling the function with -1 without the patch installed won't crash.

[Thorham]

How can you be sure of that, not having heard the 1083 ?

Because the 1083 is highly unlike to produce hi-fi level sound. If that monitor produces better quality sound than decent 50 Euro headphones, then that's absolutely astonishing. Won't believe it until I hear it

Originally Posted by meynaf

I know how good headphones can sound. They damage the bass, even if of course you still hear them. They raise high frequencies.

Good headphones don't damage the sound quality. What model would you call good?

Originally Posted by meynaf

It's just my money that would be blown away.

It depends on what you want.

Originally Posted by meynaf

250 euros for just headphones ?

Yes. You can't get good ones for 10 bucks. Same with loudspeakers. Good ones cost cash.

Originally Posted by meynaf

The point isn't that. The trick is that you can't be sure that calling the function with -1 without the patch installed won't crash.

So what? With the patch it can't crash, because the original function isn't called.

Anyway, I'm probably not going to do it. I forgot about the color table functions. Having to deal with those means modifying the calling program's allocated memory, and I'm not copying those tables over.

[meynaf]

Originally Posted by Thorham

Because the 1083 is highly unlike to produce hi-fi level sound. If that monitor produces better quality sound than decent 50 Euro headphones, then that's absolutely astonishing. Won't believe it until I hear it

Headphones don't produce hifi level sound either, or we have to first agree on the definition of "hifi".

Yes the monitor does produce a better quality sound than decent 50-eur headphones.
You may come to hear it, m'kay

That said, of course, nothing values a good hifi system with 7-band equalizer fine tuned for the miggy

Originally Posted by Thorham

Good headphones don't damage the sound quality. What model would you call good?

What model would i call good ? Now that you ask, i think it might well be 'none'

Originally Posted by Thorham

So what? With the patch it can't crash, because the original function isn't called.

I'm speaking about what happens without the patch.

Originally Posted by Thorham

Anyway, I'm probably not going to do it. I forgot about the color table functions. Having to deal with those means modifying the calling program's allocated memory, and I'm not copying those tables over.

If you're not going to do it, then this whole thread is pointless

[matthey]

Originally Posted by Thorham

Yes. You can't get good ones [head phones] for 10 bucks. Same with loudspeakers. Good ones cost cash.

I recently bought some Logitech h110 head phones from Walmart for 15 bucks and was very impressed. They don't have as much base as a sub-woofer but they have descent base. The clarity and higher pitches are amazing for such cheap head phones. I actually bought them as much for the microphone (in game voice chat) which is also very good quality. I play Dungeons and Dragons Online multiplayer with family and friends and I have to say that the sound quality of even cheap PCs have exceeded the Amiga (which still sounds good today considering the old and low specs). The DDO stereo effect in a 3D environment reminds me of a modern re-implementation of the Dungeon Master 3D environment sound. My "multimedia" PC is only about a $300 U.S. setup as DDO does not have high requirements. Too bad the Amiga elites block affordable hardware, 68k AmigaOS development and standardization so games like this will never happen on the Amiga.

[Thorham]

Originally Posted by meynaf

Headphones don't produce hifi level sound either

That's, of course, not true. I don't know where you're getting that from.

Originally Posted by meynaf

Yes the monitor does produce a better quality sound than decent 50-eur headphones.

When was the last time you heard headphones? Which ones did you hear? What kind of audio source? What kind of sound system?

With what I have at home it seems completely inconceivable that a Commodore monitor is better. My headphones certainly don't damage the bass and they don't increase the high frequencies, either. Headphones that do that are crap.

Originally Posted by meynaf

That said, of course, nothing values a good hifi system with 7-band equalizer fine tuned for the miggy

A simple stereo amp is already a million times better than those built-in crapz0r ampies.

Originally Posted by meynaf

What model would i call good ? Now that you ask, i think it might well be 'none'

People shell out over a thousand bucks for headphones. I'm sure they'd do that just to get a lower sound quality than cheapo built-in speakers

I'm also pretty sure that there wouldn't be a dedicated headphones forum for headphone enthusiasts if headphones were all bad.

There was undoubtedly a time when headphones weren't very good, just like flat panels. But those times are gone.

Originally Posted by meynaf

I'm speaking about what happens without the patch.

Yes, but does it matter? If you don't get crashes with the patch, that's better. I also doubt it would crash, actually. The documentation specifically says that out of range indexes do nothing. This implies that the input value is tested against a range (which it should).

Originally Posted by meynaf

If you're not going to do it, then this whole thread is pointless

Well, maybe it's not so bad to copy the table. What software changes the color table in a tight loop anyway?

[Thorham]

Originally Posted by matthey

I recently bought some Logitech h110 head phones from Walmart for 15 bucks and was very impressed.

I'd like to hear that...

Originally Posted by matthey

I have to say that the sound quality of even cheap PCs have exceeded the Amiga (which still sounds good today considering the old and low specs).

Of course they sound better. 14 bit can sound quite good, though.

Originally Posted by matthey

Too bad the Amiga elites block affordable hardware, 68k AmigaOS development and standardization so games like this will never happen on the Amiga.

But what's the point of trying to approach peecee specs? To me the whole charm is exactly that Amigas don't have peecee like specs. It seems far more interesting to see what can be done with AGA and a '030. I actually obtained permission to use the Grimrock 2 3D assets for an Amiga game. Should be interesting to see what's possible with full screen pre-rendered graphics.

[matthey]

Originally Posted by Thorham

But what's the point of trying to approach peecee specs? To me the whole charm is exactly that Amigas don't have peecee like specs. It seems far more interesting to see what can be done with AGA and a '030. I actually obtained permission to use the Grimrock 2 3D assets for an Amiga game. Should be interesting to see what's possible with full screen pre-rendered graphics.

I appreciate the few new classic Amiga games which push the old hardware like never before. This is difficult though, requiring low level and efficient code often using old tools. We need to make Amiga programming easier and more available to attract programmers and developers. Higher spec and more affordable hardware is one of the easiest ways to achieve this (it will still not have PC hardware specs but could be more efficient much like a console). Right now, the Amiga is a tech follower instead of leader. There is still great untapped potential for online games when many Amigas aren't even online. I suppose you don't play PC games with all the libraries of Amiga games coming out? You never wished the Amiga could play those games and never developed any ideas from PC games? The Amiga was once a creative platform but now most of the software is decades old ports. What is left of the Amiga is declining and dying as the old users age. Many Amiga users gave up and have already left for greener pastures. Who is going to play your game in 10 years?

[Thorham]

Originally Posted by matthey

This is difficult though, requiring low level and efficient code often using old tools.

It's a challenge, which, for me, is part of the fun. As for tools, all you really need is a good editor and a good assembler. The only annoying things about developing on an Amiga (for me) are the lack of memory protection and enough sanity checks in the OS.

Originally Posted by matthey

We need to make Amiga programming easier and more available to attract programmers and developers.

That's only going to happen when people are actually interested in the platform. People need more reasons than that to start working with such a niche system.

Originally Posted by matthey

Higher spec and more affordable hardware is one of the easiest ways to achieve this (it will still not have PC hardware specs but could be more efficient much like a console).

Same problem as above.

Originally Posted by matthey

Right now, the Amiga is a tech follower instead of leader.

The time of Amiga being a leader is long past, and likely won't ever return. Certainly not with things like a pi costing chicken feed.

Originally Posted by matthey

There is still great untapped potential for online games when many Amigas aren't even online.

Not necessarily a big deal. The only problem is connectivity for non A600/1200.

Originally Posted by matthey

I suppose you don't play PC games with all the libraries of Amiga games coming out?

I almost exclusively play peecee games. Just about the only game I play on my Amiga is meynaf's Dungeon Master port, and that's because it's a genuinely good game, even with it's dated graphics, and holds up very well to games like the Grimrock games.

Originally Posted by matthey

You never wished the Amiga could play those games

Not that much, no. Only when I see games that may work on Amigas in some nice form, like Grimrock, which could be great with pre-rendered graphics. Games like Fire Emblem and Advance Wars would work well, too. There are probably a few others I haven't played.

But for the rest, why? I have no problem with using my peecee for most games. It's also very easy. Just download from Steam and play. Amiga will never have that.

Originally Posted by matthey

The Amiga was once a creative platform but now most of the software is decades old ports. What is left of the Amiga is declining and dying as the old users age. Many Amiga users gave up and have already left for greener pastures.

Yes, but that's to be expected. Amigas are a thing of the past. An important part of early modern computers, but a thing of the past never the less.

It's also the best retro platform, and I'd like to keep it that way. What's the point of turning an Amiga into glue logic by adding ghz CPUs, 3D graphics cards and sound cards? I also already have stuff like that and don't need an Amiga for it.

To me, trying to force Amigas to be what they're not is a pointless exercise. I'd rather see better software that's engineered to perfection, because Amigas as they are now can do much better. Especially the OS could be miles better on 68020+ with fastmem.

[meynaf]

Originally Posted by Thorham

That's, of course, not true. I don't know where you're getting that from.

I could have said the exact same thing to you

Originally Posted by Thorham

When was the last time you heard headphones? Which ones did you hear? What kind of audio source? What kind of sound system?

With what I have at home it seems completely inconceivable that a Commodore monitor is better. My headphones certainly don't damage the bass and they don't increase the high frequencies, either. Headphones that do that are crap.

Seems we're not getting anywhere. The only way to check would be a real comparison...

Originally Posted by Thorham

A simple stereo amp is already a million times better than those built-in crapz0r ampies.

And also a million times better than any headphones you can find.
This is really getting nowhere.

Originally Posted by Thorham

People shell out over a thousand bucks for headphones. I'm sure they'd do that just to get a lower sound quality than cheapo built-in speakers

I'm also pretty sure that there wouldn't be a dedicated headphones forum for headphone enthusiasts if headphones were all bad.

There are no longer monitors with built-in speakers nowadays, so people are looking for alternatives.

Originally Posted by Thorham

There was undoubtedly a time when headphones weren't very good, just like flat panels. But those times are gone.

Or maybe people just got used to them. Like they got used to MP3 in spite of the poor quality.

Originally Posted by Thorham

Yes, but does it matter? If you don't get crashes with the patch, that's better. I also doubt it would crash, actually. The documentation specifically says that out of range indexes do nothing. This implies that the input value is tested against a range (which it should).

Well, this is building castles in the air. You don't have any patch for now

Originally Posted by Thorham

Well, maybe it's not so bad to copy the table. What software changes the color table in a tight loop anyway?

Changing the whole palette by calling a function for each color would indeed be a little on the stupid side.

Originally Posted by Thorham

Of course they sound better. 14 bit can sound quite good, though.

It does. If dynamics are correctly used, then there is no hearable difference with 16 bits. Only problem is the output frequency limitation.

Originally Posted by Thorham

But what's the point of trying to approach peecee specs?

Because we could then do better than real peecees. You seem to forget (or just don't know) that Amigas have always done better than peecees with a similar config on the paper. Try to imagine what we could do with todays tech.

Also you miss the fact that coding on the Amiga is a magnitude easier than coding on the peecee. I would NEVER code a whole app in pc asm !

Originally Posted by matthey

Many Amiga users gave up and have already left for greener pastures.

That's due to lack of hardware. Give me a brand new 500Mhz 68k system with decent graphics and a real Amiga keyboard, and you could even count on me to rewrite the full OS !

Originally Posted by Thorham

The only annoying things about developing on an Amiga (for me) are the lack of memory protection and enough sanity checks in the OS.

Lack of memory protection isn't exactly the reality. We still have memory protection tools. That's basic, ok but if that counts so much for you, why not writing your own memory protection tools ?

About sanity check, i don't miss that at all. My own system framework does that already (and the resource tracking as well).

Originally Posted by Thorham

I almost exclusively play peecee games. Just about the only game I play on my Amiga is meynaf's Dungeon Master port, and that's because it's a genuinely good game, even with it's dated graphics, and holds up very well to games like the Grimrock games.

Didn't know you were still playing it

Originally Posted by Thorham

It's also the best retro platform, and I'd like to keep it that way. What's the point of turning an Amiga into glue logic by adding ghz CPUs, 3D graphics cards and sound cards? I also already have stuff like that and don't need an Amiga for it.

Just putting PC hardware into the Amiga indeed doesn't make it better. It just turns it into another peecee.
Doesn't mean we don't need a few more horsepower.