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2 Games with 60hz mode, doubts

Started by Joseman, 20:30, 17 March 24

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Joseman

Hi

these days I've been doing loaders compatible with 60hz for Amstrad

This 2 games, Comando Quatro and Mad Mix game (links at the bottom of this thread) are playing the music with more speed on 60hz, but no better scroll and nothing more perceptible.

My theory is that the music is updated on int syncronizing with the Vsync, then in 60hz more calls to the music routine.



My doubts are, in CRTC 60hz mode, the CPU and GA are still on 50hz?

if this is right, then no better speed on any routine outside the ints? no better scroll, no better FPS?

I can say more, if the INT music routine is called more times on 60hz... then the routines outside de int will be more slow?

to sum up... CPC on 60hz mode doesn't have any advantage besides the display being more high? Is possible to be more slow in some cases?

Regards

https://github.com/sJoseman/amstrad/blob/master/Comando%20Quatro%20%5BJoseman%20mass%20storage%20compatible%5D.zip

https://github.com/sJoseman/amstrad/blob/master/Mad%20mix%20game%20%5BJoseman%2C%20mass%20storage%20compatible%5D.zip


andycadley

At 60Hz you'll have less cycles per frame, so the only way you'll see a speed up is if a game spends a lot of time HALTed waiting. In the worst case (most of the frame time consumed then HALT, the frame rate may actually drop.

Bear in mind that the CPC is doing a lot with the CPU, unlike consoles like the NES, SNES, Genesis, where the auxiliary hardware often carries most of the load.

McArti0

60 Hz has 5 int per frame and frame has 260 lines. That's all.
CPC 6128, Whole 6128 and Only 6128, with .....
NewPAL v3 for use all 128kB RAM by CRTC as VRAM
TYPICAL :) TV Funai 22FL532/10 with VGA-RGB-in.

Joseman

Quote from: McArti0 on 21:11, 17 March 2460 Hz has 5 int per frame and frame has 260 lines. That's all.
50hz has 6 ints if i'm not mistaken?

then on 60hz we lose 1 int but more time per int?





Joseman

Quote from: andycadley on 21:08, 17 March 24At 60Hz you'll have less cycles per frame, so the only way you'll see a speed up is if a game spends a lot of time HALTed waiting. In the worst case (most of the frame time consumed then HALT, the frame rate may actually drop.

Bear in mind that the CPC is doing a lot with the CPU, unlike consoles like the NES, SNES, Genesis, where the auxiliary hardware often carries most of the load.
it's interesting the HALT waiting, i wan't thinking about halt...

do yo have in mind some game that use the halt wainting a lot to make a test on 60hz mode?

andycadley

Quote from: Joseman on 21:48, 17 March 24then on 60hz we lose 1 int but more time per int?
No, it would be the same time per int. The horizontal line length is the same and we get an int after a fixed number of lines. There are just less lines per frame.

Quote from: Joseman on 21:51, 17 March 24it's interesting the HALT waiting, i wan't thinking about halt...

do yo have in mind some game that use the halt wainting a lot to make a test on 60hz mode?


Not off the top of my head. And it doesn't strictly have to be HALT, just busy looping checking for flyback would have the same effect. In fact I'd forgotten there may be less ints, so code which is counting them and assuming there are 6 per frame may have other unwanted side effects whilst still not running any faster.

I suspect running games designed on 50Hz systems at 60Hz will cause more problems than it solves. The issue was usually the other way around on the consoles, the games designed for 60Hz ran slower and weren't really taking advantage of the extra CPU time available to them.

Joseman

Hi

i found a game that uses ints for sprites: Commando.

I made a 50/60hz and mass storage friendly loader (well the original loader was mass storage friendly too)

@andycadley Test the game in 60hz mode if you can and tell me what do you think about it.

https://github.com/sJoseman/amstrad/blob/master/Commando%20%5BJoseman%2C%20Mass%20Storage%20Compatible%5D.zip

eto

isn't there also the problem that the (official) monitor starts to roll when you switch between 50/60Hz? Sure you can adjust it but I guess it's quite annoying if that happens every time you start the game or reset the computer. 

Joseman

Quote from: eto on Yesterday at 10:18isn't there also the problem that the (official) monitor starts to roll when you switch between 50/60Hz? Sure you can adjust it but I guess it's quite annoying if that happens every time you start the game or reset the computer.
Yes, you need to adjust the CPC monitor, I'm using a surveillance monitor compatible with 60hz, any TV is compatible too.

XeNoMoRPH

your amstrad news source in spanish language : https://auamstrad.es

andycadley

I don't have suitable hardware to test it on, but I can't say I can see an appreciable difference in that video. It'd also be interesting to see the end of level bit as that's probably where the most sprites come onto the screen and where it's therefore most likely to start running out of cycles.

Having to constantly fiddle with v-hold would also have made it a bit of a non-starter back in the day (admittedly modern displays probably just cope but it's not quite the same).

Joseman

Quote from: andycadley on Yesterday at 11:09I don't have suitable hardware to test it on, but I can't say I can see an appreciable difference in that video. It'd also be interesting to see the end of level bit as that's probably where the most sprites come onto the screen and where it's therefore most likely to start running out of cycles.

Having to constantly fiddle with v-hold would also have made it a bit of a non-starter back in the day (admittedly modern displays probably just cope but it's not quite the same).

I think that the soldiers are more speedy, i reach zone 3, no problem with the end level.

Of course with a real monitor looks better, and (I think) more high than in ACE.

XeNoMoRPH

Quote from: andycadley on Yesterday at 11:09I don't have suitable hardware to test it on, but I can't say I can see an appreciable difference in that video. It'd also be interesting to see the end of level bit as that's probably where the most sprites come onto the screen and where it's therefore most likely to start running out of cycles.
Having to constantly fiddle with v-hold would also have made it a bit of a non-starter back in the day (admittedly modern displays probably just cope but it's not quite the same).

I have changed the video for a new one, captured from a real machine.

your amstrad news source in spanish language : https://auamstrad.es

McArti0

And now 75Hz or ... EGA v50Hz - H22kHz 8 ints
CPC 6128, Whole 6128 and Only 6128, with .....
NewPAL v3 for use all 128kB RAM by CRTC as VRAM
TYPICAL :) TV Funai 22FL532/10 with VGA-RGB-in.

Joseman

Quote from: McArti0 on Yesterday at 13:46And now 75Hz or ... EGA v50Hz - H22kHz 8 ints
I tried 75HZ already, but my monitor doesn't support this resolution.

are there any crt tv/monitor 15khz with such hertzs?

McArti0

Quote from: Joseman on Yesterday at 18:12are there any crt tv/monitor 15khz with such hertzs?
Green GT65 up to 88Hz  768x168  3,5 int 182 line.
CPC 6128, Whole 6128 and Only 6128, with .....
NewPAL v3 for use all 128kB RAM by CRTC as VRAM
TYPICAL :) TV Funai 22FL532/10 with VGA-RGB-in.

lightforce6128

Back in the days, I had a CPC 6128 combined with a green monitor. After initialization, the operating system does no longer care about the screen frequency. There was a short BASIC command to switch the display to 60 Hz. When writing text (longer programs, homework for school, etc.), I did this regularly, because it clearly reduces image flickering, what could be tiring for the eyes. As far as I remember, adjustment of the screen was necessary sometimes, but not always. There was a position of the control dial where both display frequencies (50 Hz and 60 Hz) were stable, although this required some fiddling. The normal EDIT command or the text processing software I used did not have problems with the shortened frame time or less interrupts per frame. But for tightly optimized games, this is something completely different.

So, besides of making games (maybe) faster, 60 Hz are also much more comfortable for the eyes.

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