AtariXL vs C64

category: general [glöplog]
From all the 8bits the AtariXL has the most impressive demos in code I have ever seen. I see that it's 1.67Mhz so 1.67 times more fast than C64 in that aspect and the CPU and opcodes are the same. But wonder why do I see such detailed 3d in number of polygons that not even the 1/4 I don't see at the C64? I was watching the demo "The Shrine" (http://uk.youtube.com/watch?v=vv9zY6ei8vI&feature=related) and I was blown off because for example the sierpinski 3d gasket is not an object recomended for a slow 8bit but here it's smooth enough for it's number of polygons and shaded and clipped polygons behind (z-buffered?) and shit (and nice shades because of the pallete), ok it's 4*4 but the 3d mesh is complex for 8bits. Usually in 8bits you see a cube a pyramid or something with 10-20 polygons at most in such speed. Even for 16 bit computer it would be sometimes hard to render that gasket. Or does the big memory of 800xl makes the difference? Maybe, they store tons of precalculated data of a 3d animation for esential stuff that take few data per frame like the rotated normals, maybe some small data for clipped polygons, etc? What does it make the difference and 800xl demos are sooooo fucking awesome in code?
added on the 2008-01-19 14:53:06 by Optimus Optimus
Pfff... gameboy colour is a lot better.
added on the 2008-01-19 16:04:42 by xernobyl xernobyl
Animations do indeed kick ass :)
added on the 2008-01-19 16:25:48 by britelite britelite
Not saying that The Shrine is animations, as it actually does run without tons of memexpansions =)
added on the 2008-01-19 16:28:05 by britelite britelite
Afaik most (if not all) serious XL demos like Numen were made utilising a not official memory expansion unit (building it includes soldering the main borad of the machine) which gives 320k(!) memory for the machine. You can prerender/precalcualte lots of vector data in that extra RAM. The CPU difference is also there. I think you answered your own question. :)

(In contrary 99% of C64 demos runs on non expanded hardware, using a stock machine like it came out in 1982.)
added on the 2008-01-19 16:31:30 by Clarence Clarence
i like those palettes even if they are single spreads. quite impressive stuff
added on the 2008-01-19 16:32:39 by uns3en_ uns3en_
Yeah memory expansion is cheating. ;)
added on the 2008-01-19 17:00:06 by doomdoom doomdoom
No, but precalc is :)
added on the 2008-01-19 17:18:06 by El Topo El Topo
eh precalc is cheating? wtf?
added on the 2008-01-19 17:50:22 by skrebbel skrebbel
Demomaking is cheating.
added on the 2008-01-19 18:16:51 by Optimus Optimus
Numen require a 320Kb RAM expansion only for storing all the differents parts and to avoid loadings break while the demo is running. Not sure about it but I think i've seen a version of Numen for unexpanded XL somewhere.
Precalc is indeed cheating..
The term realtime was about NOT using lookup tables..
One could say "i look up the values in realtime though" :)

Today lookuptables are part of "code optimization" :D

and btw..
scene is dead in case you didn't notice..
added on the 2008-01-19 19:01:20 by medron medron
Strange. It was mostly in the past that people went mad and shouted "realtime of course" in their demos, exactly the times when lookuptables were necessary :)

Other than joking, I think realtime means that the effect is not a precalculated video, no matter if it uses lookuptables or not. And in the fastest effects in the 8bits the lookuptable values are actually inside the huge unrolled codes themselves that write direct values instead of retreiving them from somewhere else in memory.

And yes the scene is dead when we are dead.
added on the 2008-01-19 19:33:54 by Optimus Optimus
It's fascinating to see how computers that were dominated by the C64 in old-school demos (Sprites, Scrollers, Hi-Res etc.) are now taking their revenge in new-school effects, such as the Atari XL and the ZX Spectrum.
The XL certainly benefits from a faster CPU, a more flexible graphics chip and more RAM certainly doesn't harm either, whether some people consider it cheating or not.

Speaking about cheating: "Real time" is easy to achieve on a 2.4GHz quad-core system.
On a limited system such as a C64, an Atari XL or an Atari ST, it's not.
And demo-making has always been about "cheating smarter than the others".
added on the 2008-01-19 23:21:32 by Paranoid Paranoid
Putting lots of animation data in some extra RAM that wasn't there on the original machine is like the opposite of doing impressive realtime effects on oldschool hardware.
added on the 2008-01-19 23:33:07 by doomdoom doomdoom
doom: if an effect is an anim on these machines, it is easily spottedm like a polish a8 demo that loaded from 4 disks for a single effect :)
added on the 2008-01-20 00:39:36 by すすれ すすれ
added on the 2008-01-20 00:39:57 by すすれ すすれ
the biggest advantage of Atari in 3d stuff is graphics chip (Antic) - Atari had hardware 4x4 chunky mode, on C64 you must "emulate" it by doubling scan lines or using special charset and emulate this mode on chars - I suppose that both method are really expensive and eats a lot of CPU time... I think that Atari is about 2 to 2.5 times faster than C64 in 4x4 chunky mode... this is a reason that 90% of Atari demos use this mode...

I bet that on standard resoultion (160x200/320x200) Atari isn't much faster at all...

Grimmy had right - most of the XL/XE demo use expanded memory only for keep demo parts, not for effect itself...

britelite, Battle Droid and other "precalc" guys: here is a prove that Sierpinski is 100% realtime and run on 64k machine: use joystick to rotate object (hold fire to rotate about z-axis)

and BTW: the Shrine run on stock machine...
added on the 2008-01-20 00:59:20 by pr0be pr0be
@pr0be: thanks for the information. it was really helpful.
added on the 2008-01-20 01:20:34 by Skate Skate
Numen require a 320Kb RAM expansion only for storing all the differents parts and to avoid loadings break while the demo is running. Not sure about it but I think i've seen a version of Numen for unexpanded XL somewhere.

after watching numen i can say that i only believe you if you by "parts" mean "individual frames" ;D
added on the 2008-01-20 01:30:19 by linde linde
***************** This thread is useless, C64 rocks ATARI always. The XL is sucking the cock of the vic. This topic is gone for decades. Go blame yourself. Without "numen" the atari would be dead since the beginning ;) ********************* So what? We have computer which can beat your computers! Even loading with music is possible...
added on the 2008-01-20 02:41:37 by vscd vscd
Sierpinksi in Realtime? Is done in approximately 25 Lines of 6502-Assembler... some adjustments and it's even dancing: http://pouet.net/prod.php?which=13112 ;)
added on the 2008-01-20 02:47:44 by vscd vscd
vscd you massive spastic, did you actually look at the sierpinski in the shrine?