Amiga Animation and CHIP RAM versus FAST RAM

[amigaksi]

>As for the Graphic superiority of the Amiga- well overall I agree the Amiga was better- but I would argue and have some proof from pictures I've made using Spectrum 512, that some things at 320x200 looked better than the Amiga Ham-6 pictures.

I have one of those pictures you linked to in a Newtek Demo and it's better on the Amiga-- there are more shades in the picture.  The Atari ST is limited to 8 shades/color whereas Amiga is 16 shades/color.

> Spectrum 512 wasn't just a 16 colors per scan line program like Apple IIGS graphics were, you could display almost 50 unique colors per scan line- this offered some advantages over HAM-6 which had to modify one of the 16 unique colors RGB values to display up to 4096 colors- the look would look smudgy at times. I had fun converting GIF and BMP pictures to HAM-6 and Spectrum 512. Amiga wasn't always better...

I would not give credit for scan line changes to Apples IIGS-- they were trying to imitate the Atari/Amiga DLI/CLI on their platform.  I heard that Newtek invented a mode called Dynamic HAM which changed colors every scan line in HAM mode to prevented that problem where you had to wait up to 3 pixels to change a RGB completely.  Perhaps, someone knows the link to that new mode.

By the way, you mentioned Mega ST w/4MB RAM for animations; well if you are going to go to high end machines, I just ran that same code on the Amiga 4000 and it does 120fps in 16 color mode and 85 frames/second in HAM-6 mode.  And that code was brute force frame painting with no compression.

[Rowbeartoe]

amigaksi wrote:

"I have one of those pictures you linked to in a Newtek Demo and it's better on the Amiga-- there are more shades in the picture.  The Atari ST is limited to 8 shades/color whereas Amiga is 16 shades/color."

That picture was an Amiga picture just converted to Spectrum 512- so of course it would look better on the Amiga- I'd love to have the orginal photograph and then convert it to Spectrum 512- otherwise at best, it can only look the same.  BTW- two of those pictures were also VGA 256 color GIF pictures converted as well (I wonder how they would look in HAM-6?.  The picture on the top right I believe was an Amiga SHAM picture converted to Spectrum 512 format- so that too would look better on the Amiga since that's what it was.

SHAM was HAM-6 per scan line, so same limitations only you get a fresh 16 colors every line.  Sham was soon after I left the computer store I believe.  1990 probably or even later- and by that time- Amiga and Atari had better machines available.  I'm sure there was better hacks after Spectrum 512 for Atari ST as well to display more colors per scan line with overscan etc.  But back to my comparison- around 1987-1989 the software available for the ST and Amiga used HAM-6 and Spectrum 512 for animations.


amigaksi wrote:

"By the way, you mentioned Mega ST w/4MB RAM for animations; well if you are going to go to high end machines, I just ran that same code on the Amiga 4000 and it does 120fps in 16 color mode and 85 frames/second in HAM-6 mode. And that code was brute force frame painting with no compression."

I mentioned the Mega ST4 because it was available in 1987 about the same time Amiga released the 500 and 2000.  As I'm sure you know, the 500 and 2000 were basicly a 1000 with either more expansion slots, or a closed case like the 1040ST.  The Mega ST2/4 offered the ST its first Blitter Chip and limited expansion- it was more like the Amiga 1000.  These computers are what I'm trying to compare for animation speed as these were what was available when I was a computer salesman.  By 1990- Atari released the STE (4,096 colors, blitter, better sound) and the TT- the first true next generation Atari after the ST.

But lets get back to my question.. this can get way out of hand.  =)

Thanks again everyone for your help.

[bloodline]

Rowbeartoe wrote:

By 1990- Atari released the STE (4,096 colors, blitter, better sound) and the TT- the first true next generation Atari after the ST.

Note that while the STE palette was 12bit (like the OCS Amiga) upgraded from the ST's 9bit palette, it was still only able to display 16 colours at any one time on the screen without the interrupt tricks we have already mentioned.

You must not confuse the palette width with the display depth.

If the palette width of the STE is 12bit, that means each colour gun has 4 shades associated with it... But the STE's RAMDAC can only hold 16 of these 12bit colour registers, this means that the display has a 4bit depth... So each of the 16 colours that can be displayed can be any one of 4096 colours.

And the addition of 2 PCM audio channels isn't really much of an improvement over the original ST... Certainly nothing on the Amiga's 4 PCMs :-)

[Rowbeartoe]

Like I said we can easily get side trackd from my question on this forum.  The STE was a slight improvement but it was overall outdated when it was released in my opinion- when compared to the Amiga 1000 or the 520ST released 5 years prior.  Lets keep with the Amiga 500/1000/2000 versus 520/1040/Mega ST RAM and Animation comparison.  Thanks again everyone.

[amigaksi]

>SHAM was HAM-6 per scan line, so same limitations only you get a fresh 16 colors every line. Sham was soon after I left the computer store I believe. 1990 probably or even later-...

It's not the same limitations since you have fresh 16 colors out of 320 pixels and the hold-and-modify option for those 16 colors.
Well, if we are talking hardware capabilities, it was possible to have a better HAM in 1985.  I'm sure people were modifying palettes on the Amiga using copper list before the dynamic HAM mode.

>But back to my comparison- around 1987-1989 the software available for the ST and Amiga used HAM-6 and Spectrum 512 for animations.

Was the animation compressed with delta compression?  How much space did it take up on the disk?

>I mentioned the Mega ST4 because it was available in 1987 about the same time Amiga released the 500 and 2000.

Didn't they make accelerated Amigas or accelerator boards by 1987?  The 120fps I got was in OCS mode on an Amiga 4000.  I got 39 fps on Amiga 500/1000 at 7.16Mhz.  

[Rowbeartoe]

I said "SHAM was HAM-6 per scan line, so same limitations only you get a fresh 16 colors every line. Sham was soon after I left the computer store I believe. 1990 probably or even later-..."

amigaksi
"It's not the same limitations since you have fresh 16 colors out of 320 pixels and the hold-and-modify option for those 16 colors.
Well, if we are talking hardware capabilities, it was possible to have a better HAM in 1985. I'm sure people were modifying palettes on the Amiga using copper list before the dynamic HAM mode."

Isn't that what I said "a fresh 16 colors every line" plus hold and modify?  Well if not, that's what I meant.  Still even so- I could do some things in Spectrum 512 that would still cause even SHAM problems.  But obviously, the reverse is possible as well- even more so with SHAM.  And like I said, by the time SHAM was available (I'm not sure if paint programs supported it?) I know the demo world was even pushing the ST with more colors on scan lines and overscan etc.  

BUT! and this is a big BUT (notice the one T) my question was to the common folk who could only make animations using programs such as Scult 3D for example or CAD 3D for the ST.  Followed by was it possible at all for the Amiga since I still witnessed demos such as Juggler (a HAM-6 demo) not doing 60fps.  Or boing (a low color demo) apparently wasn't doing 60fps either.  I know for a fact, the Atari ST did allow users of Spectrum 512 and it's 16 color programs such as CAD 3D and Cyper paint to do 60fps as well.  And the time frame of course I was asking was no later than 1989 when I was a computer salesman.  I'm just fascinated by this.  The ST got away with this apparently because of it's 16 MHZ RAM- 8MHz for 68000 and 8MHz for video.  Simple, cheap, and effective at a time when RAM was faster than CPU's.  It's MMU and Shifter chip allowed some cool intrupts too, but required major CPU time to edit the pictures, but once you put those pics in memory- BAM- you had up to 60fps 320x200 500 color page flipping animations.  Not bad at all. As for the Amiga- Well Im not sure about it's 4,096 color HAM-6 mode or it's 32/64 color modes being able to page flip at 60fps at 320x200.  Amiga clearly was graphicly more capable overall, but I'm just curious if the software or demos ever did 60fps for the Amiga 500/1000/2000.  That's all.  And if future demos could, why did the orginal ones fail?   BTW- I loved Fuji Boink on the ST- it was boing, but with raster color intrupts back in 1986.  It was the first "high color" demo I saw on the Atari ST about the same time I saw the "high color" Juggler demo on the Amiga.  Boy that was an exciting time.

Thanks everyone.


amigaksi
"Didn't they make accelerated Amigas or accelerator boards by 1987? The 120fps I got was in OCS mode on an Amiga 4000. I got 39 fps on Amiga 500/1000 at 7.16Mhz."

Yes, and by 1989 I remember Transputer boards available for everybody- Atari really went crazy with that for a bit too.  But I'm not asking about board accelartors- I put one in my ST too.  Just curious about the stalk machines, because as a saleman, I could never answer that question.  

Thanks again everyone for your help.
 

[Britelite]

As for the Amiga- Well Im not sure about it's 4,096 color HAM-6 mode or it's 32/64 color modes being able to page flip at 60fps at 320x200.  Amiga clearly was graphicly more capable overall, but I'm just curious if the software or demos ever did 60fps for the Amiga 500/1000/2000.  That's all.

Is it so damn hard to understand that the hardware is perfectly capable of full framerate pageflipped animations? I don't know why the few pieces of software you used didn't allow you to do this, but they probably had their reasons. So to put an end to this discussion: both the amiga and st (and 99% of all other computers) are able to flip screens at full framerate. The only limitation being how much memory is available for the individual frames.

[shoggoth]

JetRacer wrote:
Fun fact: even modern PC's have major difficulties working under similar conditions (read: massive MB 320x200 raw animation replayed with flawless 60hz fps). It's ofcourse the OS of Win/Linux/Mac that bogs down performance and nothing else.

I beg to differ. Having programmed low level VGA stuff, I can assure you that this is not an issue. Maybe if you're running XP with little memory and virus scanners and {bleep}, but well... that's not a proper comparison.

[shoggoth]

bloodline wrote:
And the addition of 2 PCM audio channels isn't really much of an improvement over the original ST... Certainly nothing on the Amiga's 4 PCMs :-)

Most true, no offence, didn't you sort of miss the point with the original post?

[shoggoth]

Rowbeartoe wrote:
Now when I had side by side comparisons I noticed that the Amiga 500 never could do 60fps animations?

Ofcourse it could. Maybe you watched som early Amiga material or something, because it definitely could. I remember some older games being completely crap on the amiga, since they were basically straight off ports from the ST (and bad ones, too) (for example, Bubble Bobble has a horrible framerate at times, when in fact it could run perfectly if using the sprite hardware). And for the record - I'm an Atari geek.

[shoggoth]

Rowbeartoe wrote:
Spectrum 512- well believe it or not this graphic program gave the Atari ST some advantages over Amiga HAM-6.  Spectrum 512 wasn't the standard way (Apple IIGS like) to achieve lots of colors 16 per scan line.  

I wouldn't call it an advantage over HAM at all. It's about HBL interrupts and code running synchronized with the electron beam. It chews up like 75% of the CPU, if not more, which is not the case with HAM.

Rowbeartoe wrote:
The enginneers hooked an oscilloscope to teh Atari ST MMU chip and reverse-enginneered its timers.  Using this information, they designed a method to manipulate those times and stuff more colors into extra simlulated bit planes, before the signal even gets to that Atari ST's graphic Shifter chip.

You're making it sound like rocket science, which it is not. The MMU has no timers, maybe you're referring to the MFP.

O- to understand the memory in the Atari ST- I read that the engineers gave the ST 16 MHz unified RAM- giving 8-MHz to Video, and 8-MHz to the 68000.  The ST didn't have anything fancing like CHIP RAM and FAST RAM.

Well, the TT and Falcon (and any 020+ machine) made a distinction between ST-RAM and Fast Ram, where the former could be accessed by the SDMA, blitter and shifter, and the latter could not.

Thanks everyone for still trying to resolve this.  I'm starting to accept that perhaps software engineers didn't feel pressed to push the Amiga to 60fps with there animation software.

Dude, you've got it wrong. The Amiga, and the software for it, was able to do 60fps. You've watched some old software which couldn't, and based your opinion on that. When people claim you've got it wrong, you still return to your perception from the old days. That's silly, no offence, but it really is. I'm an Atari guy too, for the record.

[shoggoth]

Rowbeartoe wrote:
My question once again was why did Juggler, Sculpt 3D, and this Demo of CAD 3D on the Amiga never allow speeds to go faster than 30fps as they did on the Atari ST?  

Perhaps because the Amiga versions of those apps were crap?
Just a theory.

[shoggoth]

Rowbeartoe wrote:
Spectrum 512 and other paint programs that followed on the ST did offer some advantage over Ham-6.  But Ham-6 had advantages 2.  But this isnt about spectrum 512 versus Ham-6.  

Spectrum 512 is not even a videomode, whereas HAM is. It cannot be compared. The Amiga could do the same thing even without using the CPU (Copper). You're talking apples and oranges.

Ok, not quotes, but anyway:
"Can the Amiga display animations at 60FPS? I've only seen 30FPS".
 - Yes.

"But I've only seen 30FPS. Can it really play at 60FPS."
 - Yes.

"But I've only seen 30FPS."
 - But it can.

"No it can't, I've only seen 30FPS."
 - Sure it can.

"But I watched this app 1988 which couldn't."
 - It can.

"No, are you sure?"

Get a grip, dude.

[meega]

@shoggoth

Hi, Atari-friend.  :-D

[Zac67]

Never heard of Spectrum 512 before, but as I understand it, it's a software hack to change the ST's palette beam synced on each scanline. Of course this puts a load on the CPU, allows for >16 colors on the screen but OTOH doesn't allow >16 colors per scanline.

The same method can be used on the Amiga, only that - of course - you'd use the Copper instead to do the palette rewrite stuff, completely supported by the OS.

Also you could use 5 bit planes to display 32 colors, use EHB or even HAM which could definitely display better colors. In other words: you could convert a Spectrum 512 pic to the Amiga (16 color lores plus dynamic palette). Actually SHAM uses the same method, so it MUST look better - provided the same care is taken when converting the pic. All examples I could find on the 'net seem to support this statement...

[bloodline]

shoggoth wrote:

bloodline wrote:
And the addition of 2 PCM audio channels isn't really much of an improvement over the original ST... Certainly nothing on the Amiga's 4 PCMs :-)

Most true, no offence, didn't you sort of miss the point with the original post?

Ok, then... on topic...

The Original poster states, from memory, he felt that the Amiga seemed to only play at 30fps when the Atari ST appeared to play at 60fps.


First off, this statement is based on apparent observation, not a testable examination, of an event that happened 18 years or more in the past.

Secondly, no one seems to be able to test this... are there really that few Atari ST's around? Does no one have the software in question?

Thirdly, in answer to the OP question... Yes the Amiga can display animations at 60fps with out problems. In fact, these animations can even be in HAM-6 mode and use very little CPU time. I or in fact anyone with a modicum of programming ability can easily write a program to prove this, if need be.

Fourthly, The ST used an alternate bus cycle design, to share the memory between the CPU and the Display chips. This means that on a 16Mhz bus, each chip only gets access to the memory half the time, ie 8MHz. On the Amiga the GFX chips could steal (dynamically allocate) cycles from the CPU if needed (beneficial since the GFX chip do most of the work on the Amiga). On a related note the Atari Scanline Interrupt trick, to increase the effective number of colours displayable (essentially a new 16 colour palette every scanline) was also available on the Amiga (and probably every other 68k based machine of the time), but it uses a huge amount of CPU time, leaving nothing left for any other code to run.

I hope that sums everything up.