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Early machines and hardware scrolling, sprites, etc. [message #101526] Fri, 04 February 2005 11:27 Go to next message
Blake  Patterson is currently offline  Blake Patterson
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It's interesting to me....

The Apple II came out in 1977 and can really be forgiven for not having
hardware assisted screen scrolling, sprites, etc. The Atari 800 came
out in 1979 and had lots of custom hardware (I think the first rev had
128 rather than 256 colors in the palette tho) for scrolling, sprites,
etc. The C64 came out in 1982 and has sprites and (it seems from what
I have recently read) hardware scrolling.

The Amiga came out with quite the custom hardware in 1985 and wowed us
all. The Amiga combined a very fast CPU with this hardware and was a
thing of beauty.

What I find odd is that the Apple IIgs came out in 1986 and did not
have a fast CPU - a 2.8MHz 65C816 w/ a 1MHz bus and had screenmodes not
unlike the Amiga and Atari ST, but lacked sprites, hardware scrolling
etc. (The ST had no gfx acceleration either, but it at least had a
fast CPU so the lack seems less grievous.) I got to thinking about
this when I was looking at Shadow of the Beast on my newly setup C64
system...

http://www.blakespot.com/list/images/c64c_1.jpg

....and was amazed at what a 1MHz 6510-based system was doing. I am
quite certain that the Apple IIgs could not have pulled that off. I
wonder why it is that there was no acceleration in the GS? And I _am_
correct tha the C64 has hardware scrolling, yes?

Was just thinking about all this, reading the threads. It seems the
Amstrad CPC had hardware scrolling as well. I guess the IIgs (and IIe
/ IIc really) were in the minority at their time of introduction.



bp
Re: Early machines and hardware scrolling, sprites, etc. [message #101527 is a reply to message #101526] Fri, 04 February 2005 12:08 Go to previous messageGo to next message
Hg[1][2] is currently offline  Hg[1][2]
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The C64 would have been even more beautiful had it possessed the Atari's
1.79Mhz CPU speed and colour palette.
Re: Early machines and hardware scrolling, sprites, etc. [message #101533 is a reply to message #101527] Fri, 04 February 2005 14:17 Go to previous messageGo to next message
Blake  Patterson is currently offline  Blake Patterson
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Yea, I can never really seem to reconcile that. The Atari had a far
greater palette and a faster CPU, but the C64 is perhaps considered the
better "graphics gaming machine." It seems the C64 can paint a 320x200
16-color screen. Could the Atari not do such a mode? It seems it
might need to run at a lower res to get that many colors onscreen?
Like the Apple II could do 280x192 in b&w pixels but 140x192 w/ color.
(560x192 w/ double high res b&w pixels but 140x192 w/ 16-color double
high res - similarly.)

Is the Atari the better game machine? There's a loaded question.

I think a lot of Free Fall's and Ozark's games were Atari first.


bp
Re: Early machines and hardware scrolling, sprites, etc. [message #101560 is a reply to message #101526] Fri, 04 February 2005 14:30 Go to previous messageGo to next message
David Murray is currently offline  David Murray
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Well, I just don't think the Apple II series was ever targeted or
marketed as a game machine, just like the IBM PC. The Apple II had
several advantages over the C64 that really boosted in for other
applications. For example, lets face it, the disk access was much
better. The speed was better, and the memory was better. The internal
expandability was also better. But its graphics and sound sucked. I
have played many games that were developed for both machines and was
always blown away how much better the C64 version was. I actually own an
Apple IIe but haven't fired it up in years. But I have copies of some of
the same games.. Just what comes to mind are: Ms. Pac Man, Spy vs. Spy,
and Ghostbusters. The C64 version of each of these are way better.

Not only that.. but honestly I prefer to use an Apple II on a black and
white monitor. I'd rather not see the terrible color skew that you see
on plain text. Since most anything I'd do with one would be a black &
white type application anyway.
--DavidM

"Blake Patterson" <blakespot@gmail.com> wrote in
news:1107534469.719450.52490@g14g2000cwa.googlegroups.com:

> It's interesting to me....

>

> The Apple II came out in 1977 and can really be forgiven for not having

> hardware assisted screen scrolling, sprites, etc. The Atari 800 came

> out in 1979 and had lots of custom hardware (I think the first rev had

> 128 rather than 256 colors in the palette tho) for scrolling, sprites,

> etc. The C64 came out in 1982 and has sprites and (it seems from what

> I have recently read) hardware scrolling.

>
Re: Early machines and hardware scrolling, sprites, etc. [message #101563 is a reply to message #101560] Fri, 04 February 2005 16:35 Go to previous messageGo to next message
Blake  Patterson is currently offline  Blake Patterson
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The Apple II was the 8-bit machine that I primarily used back in the
day. I have an Apple IIgs now to run the full lot of Apple II
software. The color skew is not a problem with an RGB monitor tied to
the IIgs.

On the IIgs, G = graphics, S = sound. It is curious to me that we did
not see some hardware assistance in the animation department on that
machine that was released in 1986. It had much better sound hardware
than even the Amiga, but it was held back by only 64K of audio RAM.


bp
Re: Early machines and hardware scrolling, sprites, etc. [message #101564 is a reply to message #101563] Fri, 04 February 2005 16:41 Go to previous messageGo to next message
de Selby is currently offline  de Selby
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> On the IIgs, G = graphics, S = sound. It is curious to me that we did

> not see some hardware assistance in the animation department on that

> machine that was released in 1986. It had much better sound hardware

> than even the Amiga


....but you need expensive third party hardware to make use of it.
Re: Early machines and hardware scrolling, sprites, etc. [message #101570 is a reply to message #101564] Fri, 04 February 2005 17:10 Go to previous messageGo to next message
Blake  Patterson is currently offline  Blake Patterson
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No, you don't, actually.

The IIgs has a small internal speaker and a 1/8" headphone jack. The
heaphone jack outputs the IIgs' Ensoniq DOC's audio in mono only.
There is a connector inside the machine that breaks out the audio
signals. Users wanting the sound in stereo would typically add a
stereo card that sat in a slot to draw power and had a ribbon cable
connecting to the sound connector to get at the stereo signal. The
card amplified the signal and provided an 1/8" stereo headphone jack.
Often the cards contained hardware that allowed sampling of audio to
disk.

It is possible to build a stereo card and many users did so. Or you
can make due with mono sound. You definitely did not need any hardware
to hear the GS' 32-oscillator sound in full quality (if mono).



bp
Re: Early machines and hardware scrolling, sprites, etc. [message #101574 is a reply to message #101526] Fri, 04 February 2005 17:50 Go to previous messageGo to next message
Cameron Kaiser is currently offline  Cameron Kaiser
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This is more comp.sys.apple2 territory, but what the heck.

"Blake Patterson" <blakespot@gmail.com> writes:

> What I find odd is that the Apple IIgs came out in 1986 and did not

> have a fast CPU - a 2.8MHz 65C816 w/ a 1MHz bus and had screenmodes not

> unlike the Amiga and Atari ST, but lacked sprites, hardware scrolling

> etc. (The ST had no gfx acceleration either, but it at least had a

> fast CPU so the lack seems less grievous.) I got to thinking about

> this when I was looking at Shadow of the Beast on my newly setup C64

> system...

> http://www.blakespot.com/list/images/c64c_1.jpg

> ...and was amazed at what a 1MHz 6510-based system was doing. I am

> quite certain that the Apple IIgs could not have pulled that off. I

> wonder why it is that there was no acceleration in the GS? And I _am_

> correct tha the C64 has hardware scrolling, yes?


The C64 has hardware fine scrolling, although you have to do the
heavy lifting for coarse scrolling.

The IIgs should not have been as crippled as it was (I'm a IIgs owner;
I have a Woz converted to ROM 03 with 2MB of RAM, an AE SCSI card and
drive, and GS/OS; I'll get a ZipChip one of these days). The reason
was very simple: Apple didn't want to be in the Apple II line anymore,
and didn't want people flocking to the IIgs when they should have been
buying a Macintosh. As a result, the CPU speed was intentionally
crippled.

Nevertheless, the IIgs does have nice graphics and sound, and the 65816
in that unit is "good enough." It just could have been better, and the
lousy part is that it was not better, on purpose.

--
Cameron Kaiser * ckaiser@floodgap.com * posting with a Commodore 128
personal page: http://www.armory.com/%7Espectre/
** Computer Workshops: games, productivity software and more for C64/128! **
** http://www.armory.com/%7Espectre/cwi/ **
Re: Early machines and hardware scrolling, sprites, etc. [message #101580 is a reply to message #101533] Fri, 04 February 2005 18:34 Go to previous messageGo to next message
Peter van Merkerk is currently offline  Peter van Merkerk
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Blake Patterson wrote:
> Yea, I can never really seem to reconcile that. The Atari had a far

> greater palette and a faster CPU, but the C64 is perhaps considered the

> better "graphics gaming machine." It seems the C64 can paint a 320x200

> 16-color screen.


It can, but there are restrictions though. You can have only two colors
(out of palette of 16 colors) in every 8x8 pixel block. Suppose you want
to paint a blue and a red line that cross each other on a black
background (so in total 3 colors). Everything is fine with exception of
the pixel block in which the lines cross. In that pixel block the red
line has to be draw blue or the blue line has to be drawn red. This
effect is known as color bleeding. The C64 is not unique in this
respect; there are several other home computers, like the Sinclair
Spectrum which have similar restrictions. There are undocumented tricks
to improve the color resolution, but since these require very acurate
timing and a lot of CPU time, they are rarely used except for demos.
Because of the color restictions in the 320x200 mode, many programs use
the 160x200 mode, which can display 4 colors in every 4x8 pixel block.

> Could the Atari not do such a mode? It seems it

> might need to run at a lower res to get that many colors onscreen?

> Like the Apple II could do 280x192 in b&w pixels but 140x192 w/ color.

> (560x192 w/ double high res b&w pixels but 140x192 w/ 16-color double

> high res - similarly.)


Both the Atari and the C64 have only a limited amount of memory for
display purposes. In both cases the video memory is insufficient to
display 320x200 with 16 colors without restrictions. Atari deals with
this by lowering the number of colors or lowering the resolution, the
C64 deals with this by making some restrictions on the number of colors
that can be displayed within a pixel block.

I'm not too familiar with the Atari, but I believe one can increase the
total number of colors shown simultaneously on a screen by using display
lists. But the number of possible colors on a single line would still be
restricted to 4.

> Is the Atari the better game machine? There's a loaded question.


It is not just about numbers; for example the hardware sprites on the
C64 are much more flexible that the player/missile graphics found on the
Atari. From the hardware perspective I think the C64 is a better
balanced machine. The relatively weak CPU is more than compensated by
the video and audio chips. If it only would have had a faster disk drive
and more colors...
Re: Early machines and hardware scrolling, sprites, etc. [message #101581 is a reply to message #101574] Fri, 04 February 2005 18:41 Go to previous messageGo to next message
Blake  Patterson is currently offline  Blake Patterson
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I, too, have a IIgs currerntly and enjoyed one during '87-'88. Current
IIgs has:

- 500MB Focus IDE hardcard
- ZipGS accelerator
- 5.125MB RAM (SiriusRAM card)
- SoundMeister stereo card
- 2x 3.5", 1x 5.25" floppy
- ROM 03 mobo in a Woz case

I guess I am answering my own question here a bit, but I knew the GS
was intentionally crippled at the CPU, but keeping a slowish CPU and
adding some hardware accelerated gfx would still keep the computational
power down, reducing the competition w/ Mac. Well, the GS does have
FillMode. :-)

I don't think the GS could pull off Shadow of the Beast graphically,
though. Not that much animation. I kept a close watch on my friend
Arnold Kim (runs MacRumors.com now) who coded some GS demos in asm back
in the late 80's - Nemesis Productions. What he showed me of the GS'
outer limits falls short of SOTB on the C64.



bp
Re: Early machines and hardware scrolling, sprites, etc. [message #101583 is a reply to message #101580] Fri, 04 February 2005 18:45 Go to previous messageGo to next message
Blake  Patterson is currently offline  Blake Patterson
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Yes Spectrum graphics make the limitation quite visible and obvious.
Much moreso than the C64. Are you sure the C64 is as limited as you
describe? Looking at the gfx it seems not so while, again, it is
obvious on the Spectrum.

Spectrum allows I think 2 colors/ 8x8 block if I am not mistaken.

So can the C64 scroll the entire screen w/ little CPU impact?



bp
Re: Early machines and hardware scrolling, sprites, etc. [message #101596 is a reply to message #101583] Fri, 04 February 2005 22:37 Go to previous messageGo to next message
White Flame \(aka Dav[1] is currently offline  White Flame \(aka Dav[1]
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"Blake Patterson" <blakespot@gmail.com> wrote in message
news:1107560714.419887.214810@f14g2000cwb.googlegroups.com...
> Spectrum allows I think 2 colors/ 8x8 block if I am not mistaken.


Yep, same as c64's hires mode, but their bitmap layout is wonky in a
different way, iirc.

> So can the C64 scroll the entire screen w/ little CPU impact?


The 64 has finescroll of 8 pixels in both x/y directions. To move more than
that, redrawing the buffer is necessary, but since it's 8x8 char/tile based
in most games' modes, that only takes 1000 bytes max to redraw, which is a
whole lot faster than redrawing a bitmap.

There are also some tricks for freaking out the video chip so that it does
scroll large distances, but some of them crash older machines or are limited
to how much they can display, so they weren't used all that much in
commercial games. Demos, on the other hand, use them all the time.

--
White Flame (aka David Holz)
http://www.white-flame.com/
(spamblock in effect)
Re: Early machines and hardware scrolling, sprites, etc. [message #101603 is a reply to message #101583] Sat, 05 February 2005 05:18 Go to previous messageGo to next message
Peter van Merkerk is currently offline  Peter van Merkerk
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Blake Patterson wrote:
> Yes Spectrum graphics make the limitation quite visible and obvious.

> Much moreso than the C64. Are you sure the C64 is as limited as you

> describe? Looking at the gfx it seems not so while, again, it is

> obvious on the Spectrum.


Yes, but the advantage of the C64 is that it also has sprites which
don't have the color bleeding problem.

On the spectrum the player graphics are part of the bitmap. If the
player is moved the bitmap has to be redrawn, and if the player is
between two 8x8 pixel blocks with different color attributes the color
bleeding will become very appearant.

On the C64 player graphics are usually sprites which are completely
independant of the underlying bitmap.

> Spectrum allows I think 2 colors/ 8x8 block if I am not mistaken.


That is correct.

> So can the C64 scroll the entire screen w/ little CPU impact?


The C64 can scroll the screen 8 pixels both vertically and horizontally.
After that the image data has to be moved in memory. Since moving up to
10 kilobytes during the vertical retrace is more than a 6510 @ 1 MHz can
handle, scrollers use character based screen modes which require much
less bytes to be moved in memory.

--
Peter van Merkerk
peter.van.merkerk(at)dse.nl
Re: Early machines and hardware scrolling, sprites, etc. [message #101673 is a reply to message #101581] Sat, 05 February 2005 23:38 Go to previous messageGo to next message
Anton Treuenfels is currently offline  Anton Treuenfels
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"Blake Patterson" <blakespot@gmail.com> wrote in message
news:1107560474.922704.200390@f14g2000cwb.googlegroups.com...
> I guess I am answering my own question here a bit, but I knew the GS

> was intentionally crippled at the CPU, but keeping a slowish CPU and

> adding some hardware accelerated gfx would still keep the computational

> power down, reducing the competition w/ Mac. Well, the GS does have

> Fill Mode


I dunno - scanning through my copy of the "Apple IIgs Hardware Reference
Guide" doesn't make it seem like Color Fill Mode is all that exciting.
What's more interesting is that one of the new graphics modes is 320x200x16,
where those 16 colors represent indexes into a 16-slot palette of 12-bit
colors. So, any pixel on the screen can be one of sixteen colors selected
from a potential 4096, with no restrictions on placement.

The analog RGB output as well as composite video is also nice.

But it also appears that the screen buffer location in this mode is fixed.
There's no apparent way to do double-buffering, and that hurts animation
quite a bit.

- Anton Treuenfels
Re: Early machines and hardware scrolling, sprites, etc. [message #101711 is a reply to message #101526] Sun, 06 February 2005 09:11 Go to previous messageGo to next message
anoneds@netscape.net is currently offline  anoneds@netscape.net
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Blake Patterson wrote:
> It's interesting to me....

>

> The Apple II came out in 1977 and can really be forgiven for not

having
> hardware assisted screen scrolling, sprites, etc. The Atari 800 came

> out in 1979 and had lots of custom hardware (I think the first rev

had
> 128 rather than 256 colors in the palette tho) for scrolling,

sprites,
> etc. The C64 came out in 1982 and has sprites and (it seems from

what
> I have recently read) hardware scrolling.


<snip>

And the TI-99/4 came out in 1979, and had sprites (32 with foreground
color only, automatic motion, limited to four on a line), 256x192
screen, no bitmap and no real hardware scrolling, only page flipping.
The 99/4A came out about 1.5 years later and added bitmap, with its
color bleeding problems. But with the memory usage of this mode you
could not do page flipping.

Ben
Re: Early machines and hardware scrolling, sprites, etc. [message #101716 is a reply to message #101603] Sun, 06 February 2005 10:23 Go to previous messageGo to next message
Payton Byrd is currently offline  Payton Byrd
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Peter van Merkerk wrote:

> Blake Patterson wrote:

>

>> Yes Spectrum graphics make the limitation quite visible and obvious.

>> Much moreso than the C64. Are you sure the C64 is as limited as you

>> describe? Looking at the gfx it seems not so while, again, it is

>> obvious on the Spectrum.

>

>

> Yes, but the advantage of the C64 is that it also has sprites which

> don't have the color bleeding problem.


Interesting. That means you could draw your bitmap in 320x200 and leave
out the intersection blocks, and then use sprites to display the mixed
colors over the missing blocks. Combine this with the hacks to get more
sprites on the screen and you could have quite a complicated and color
rich image. Add in the easy ability to animate sprites and well placed
sprites over a well laid out background could accomplish some very nice
320x200 animations such as an erupting volcano or twinkling stars
through a nebula or something.


--
Payton Byrd
Homepage - http://www.paytonbyrd.com
Blog - http://blogs.ittoolbox.com/visualbasic/dotnet/
Store - http://stores.ebay.com/Collectible-Commodores-and-More
Re: Early machines and hardware scrolling, sprites, etc. [message #101719 is a reply to message #101716] Sun, 06 February 2005 11:51 Go to previous message
Peter van Merkerk is currently offline  Peter van Merkerk
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Registered: July 2003
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Payton Byrd wrote:
> Peter van Merkerk wrote:

>

>> Blake Patterson wrote:

>>

>>> Yes Spectrum graphics make the limitation quite visible and obvious.

>>> Much moreso than the C64. Are you sure the C64 is as limited as you

>>> describe? Looking at the gfx it seems not so while, again, it is

>>> obvious on the Spectrum.

>>

>> Yes, but the advantage of the C64 is that it also has sprites which

>> don't have the color bleeding problem.

>

> Interesting. That means you could draw your bitmap in 320x200 and leave

> out the intersection blocks, and then use sprites to display the mixed

> colors over the missing blocks.


You are not the first with that idea, check out the "SuperHires - SH"
part on this page:
http://www.studiostyle.sk/dmagic/gallery/gfxmodes.htm

--
Peter van Merkerk
peter.van.merkerk(at)dse.nl
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