| From: | Bart King |
| Date: | 5 Jul 2000 at 19:07:33 |
| Subject: | Re: Gfx cards + AGA |
Matt Sealey <matt@kittycat.co.uk> wrote:
> That's funny, because my system has sped up quite a bit but not because of
> a simple memory bandwidth problem: it's because the CPU is doing all the work
> and my 50MHz '060 just happens to be about 4x the speed when running at
> full whack.
Yep, because the CPU accesses Fast RAM direct, and FBlit puts it in Fast
RAM (or at least, tries to; still a few programs that will not work with it).
> In fact, I'm wondering why you even brought it up: are you always this
> pedantic? :)
You're the one that uses FBlit, and yes, I am - it's a thing that I do :)
[scrolling + layers]
> Poorly implemented how?
While I did not program the AGA chip set, don't forget it is 8 years old.
Graphics development has come along way since then, and you could even say
that AGA was what opened the eyes of hardware manufacturers for certain
graphics operations.
What Commodore did was to develop a graphics chip set which was
state-of-the-art at the time. It does amazing things if
a) You can figure it all out; don't forget that Commodore never actually
got around to releasing full-blown AGA documentation.
b) You keep resolutions television compatible
c) You bypass all system routines and program (hack) AGA direct.
Although AGA was not developed to be fixed at a specific resolution (that's
the beauty of it), the way things like layers and scrolling give poor
performance when resolutions increase.
Take for example a 320x256 screen and a 1024x768 screen - one four times
the size of the other. Memory issues aside, scrolling both screens 32
pixels to the left, would require the Blitter (not CPU) to shift all the
pixels.
BitMap's on the Amiga are planar. This is a special format used by Amiga
and only Amiga which allows shortcuts to be taken on how the graphics
chip sets figure out what should be passed to video out. Such shortcuts
include "masking" pixels in with each other to give the appearance of one
color for one or more pixels. This masking is actually a visual effect,
and works if the resolution and frame rate/frequency match up with the
video display.
The Blitter has its work cut out to shift 761,856 (992x768) pixels to the
left, where as it'll manage 73,728 (288x256) with some ease. If the
Blitter does not complete the scrolling operation before the next video
beam sweep, you'll get the effect of a blurred scrolling, which can look
cool or shit depending on how you look at it.
This method of scrolling has long been surpassed with special components on
graphics devices to handle scrolling which can achieve fast scrolling in
graphics memory at blistering speeds.
> Can you cut with the patronising speak? I'm not five.
Who's patronizing? This is a public discussion forum so I tend to word my
replies in a way the all can read, expert or not.
> How many people do you know with an AGP 4x graphics card? Now count
> on one hand the number of people you know with a motherboard capable
> of using AGP 4x.
Quite a few, believe it or not. A lot of the nerds I know seem to spend
more cash on their PC's than they spend on basic household needs :)
Been pre-advised to stay away from Voodoo 5's, even though I'll never get
one ;)
> should be on screen at any one point: on high colour screens, you get patches
> of colour which don't QUITE match and look strange. On 256 colour screens
No, the idea of using high-color displays is so you can have lots of
individual 256 color images on the same display. I don't create web
graphics, but a lot of the sites I've visited tend to use unique palettes
on all images - it's just easier, makes the graphics card sort out all the
colors.. why bother when hardware does it for you :)... oh, AGA, right ;)
> and below, you get dithering like you've never seen. I'd hate to think what
> something like a Palm would do to them...
I never have liked dithering, especially on small displays - looks far to
pixelated :)
> I can't stand 16bit graphics modes, tbh, when I'm on a PC - the dithering makes
> my eyes hurt. I don't know whether that's me being elitist, or my monitor at work
> being so damned crispy ;)
Strange, I fail to notice any dithering. Of course, 16-bit or higher
images are dithered, but most of (if not all) of the images I use tend to
have less than 32,768 colors. As long as there are less than 65,536
individual colors on the screen it's all great (no palette).
> I do it all the time.. the in-look on the 'net these days is pixellated graphics,
Argh, no :)
> So what's the difference between your large 16 bit desktop, with all this stuff
> on it, and this large (well, maximum size for a PAL screen at 724x568) 256
> colour screen with... umm.. all this stuff on?
Nothing, it's all a matter of personal taste. I like to have big, crisp,
clear fonts that I can read, vivid, clear coloring, and big views so I
don't have to keep jumping around source code. I can't stand an editor
window that's too small (i.e. less than 512x400 for example) because of
toolbars and other windows taking up space, meaning I flick between
windows.
> I even had a super-big desktop to play around with when I installed the (crap)
> HighGFX monitor drivers. I went back to PAL because frankly my eyes hurt
> trying to make out the teensy pixels.
My eyes hurt trying to figure out huge pixels :). It is all a matter of
personal taste. In the very unlikely event of me ever using your computer,
I'd reconfigure the whole thing to what I want, and you'd do the same to
mine. It's chalk and cheese.
> A graphics card is by no means a necessary thing to ANYONE unless you just
> happen to be well into 3D graphics and/or games, or some really heavy-duty
> DTP (like making a magazine). It's certainly no use to me (I doubt I'd ever pop
> out of 800x600, I need to be able to edit *pixels*!).
I have a graphics card because I'm a developer. Some people have a
graphics card too because they do high color graphics work, they like
games, or need extras that only work with graphics cards (like TV tuners,
etc.).
To a user, if you don't have a graphics card and get on with it, fine,
don't get one. But with super-powered games being released on the Amiga
(it is games that drive platforms), expect AGA support to become secondary
- that's all I'm saying.
And in regards to editing pixels, paint programs have zoom options you know
- and with a fast graphics card, you'll never notice any difference from
peering into low resolution displays :)
> Why do I need a graphics card? Because you've got one? No, I don't think so ;)
Like I said, if you don't need one, fine. Just remember developers -
mostly game developers - are getting tired of supporting AGA, it is more
work than necessary.
It's also the little things which you can't explain either ;)
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