A list of oldschool demoeffects...
category: code [glöplog]
I think the first chaos zoomer fx appeared in this intro: http://pouet.net/prod.php?which=15299
Spacecut fx, first appeared in animotion: http://pouet.net/prod.php?which=1627
is that the same as hidden vector? someone posted it earlier. thom?
what is it called the techno-part in Panic / Future Crew, where all the line-drawed images are showing fast-paced. i wonder if there is a short name for it.
http://www.home.no/rudibs/dox/demoeffects%20list.txt updated!
added "first appeared"-list since there seems too be some interest.. need to be updated in time though
added "first appeared"-list since there seems too be some interest.. need to be updated in time though
Hmmm. Yeah. Like "polar transforms" vs. "image warping" or something. whatever. :)
Space-cut/shadows is more like line clipping along horizontal/vertical axis i think, so not too complex... You search the intersection betwen the borders of your (convex?) polygon and a fixed-z plane, and thus your polygon is cut in two new (convex) polygons... But vectors in hidden lines (not filled vector) also need similar techniques iirc (see sutherland video above), but it was really rare to see those.
For shadows/intersections between complex objects (as in the excellent extension demo: http://pouet.net/prod.php?which=3038) i bet they were using rotations before and after the cutting? Or is it just z-buffer?
For shadows/intersections between complex objects (as in the excellent extension demo: http://pouet.net/prod.php?which=3038) i bet they were using rotations before and after the cutting? Or is it just z-buffer?
Space-cut is essentially today's Z buffer if I'm not wrong. you compare depth pixel by pixel and done.
oh, I have so far only seen space cut used on gouraud styled objects which cuts each other :) this amiga demo most probably doesnt use Z buffer.
so what is this then? 
magic block cutter from cd2. i thought that was space-cut too..
magic block cutter from cd2. i thought that was space-cut too..
i think the magic block scene (and there was one other with objects intersecting iirc) counts as a space-cut.
and it looks like cd2 actually clips the objects against each other: note that whenever they show intersections, only convex objects are involved.
rotate->clip against fixed plane->rotate seems completely bogus to me. just clip against an arbitrary plane directly.
rotate is between 2-3 dot products worth of work per vertex (you can get rid of 1-2 mults at the expense of a couple of adds more). so two rots comes out at at least 4. whereas arbitrary plane clip vs. fixed axis-aligned plane clip is just one dot product per vertex more.
and it looks like cd2 actually clips the objects against each other: note that whenever they show intersections, only convex objects are involved.
Quote:
You search the intersection betwen the borders of your (convex?) polygon and a fixed-z plane, and thus your polygon is cut in two new (convex) polygons... But vectors in hidden lines (not filled vector) also need similar techniques iirc (see sutherland video above), but it was really rare to see those.
For shadows/intersections between complex objects (as in the excellent extension demo: http://pouet.net/prod.php?which=3038) i bet they were using rotations before and after the cutting? Or is it just z-buffer?
rotate->clip against fixed plane->rotate seems completely bogus to me. just clip against an arbitrary plane directly.
rotate is between 2-3 dot products worth of work per vertex (you can get rid of 1-2 mults at the expense of a couple of adds more). so two rots comes out at at least 4. whereas arbitrary plane clip vs. fixed axis-aligned plane clip is just one dot product per vertex more.
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Don't know if it has been mentioned yet, but here's another oldschool effect, cybervector:
Used on char-based screens, you simply make a 2x2 box of each character to get the enlarged and 'cyberized' version of your object.
Used on char-based screens, you simply make a 2x2 box of each character to get the enlarged and 'cyberized' version of your object.
[quote]rotate->clip against fixed plane->rotate seems completely bogus to me. just clip against an arbitrary plane directly.[\quote]
You're right! Thank you for pointing out...
You're right! Thank you for pointing out...
Concerning scrolltexts with rotating chars (called snurkel scrollers), that demo came approx 1 year before darkness or silent's one: http://pouet.net/prod.php?which=11285 which isn't a surprise since mmm invented a lot of scrolltexts types.
hitchhikr: noted.
Concerning Amiga demos, what's the name given to filled circles or shapes that occupy just one bitplane each, are moved around by the Blitter, and which, when and where they overlap, produce extra colours? The circles are usually swirling around the screen.
Does anyone know?
Does anyone know?
move with blitter? nah. just move the bitplanes.
the "extra colors" are just when 2 bitplanes match and generates another color so you are able to have 32 different colors on 5 bitplanes.
Think it is called interpolarization?
the "extra colors" are just when 2 bitplanes match and generates another color so you are able to have 32 different colors on 5 bitplanes.
Think it is called interpolarization?
Quote:
Concerning Amiga demos, what's the name given to filled circles or shapes that occupy just one bitplane each, are moved around by the Blitter, and which, when and where they overlap, produce extra colours? The circles are usually swirling around the screen.
Does anyone know?
Bitplane effects? :). And it's not restricted to circles - glenz vectors, hell any form of transparency on machines with planar mode are almost always messing about with the bitplanes.
The effect is called interference.
Thank you all. I only ask because there's this one Amiga demo I've been trying to track for years now. I think it may have been ECS, since I haven't found it in the AGA section, and all I remember is it had HAM images, the "bitplane" effect as you said, and a tune so mellow and slow-paced that it lasts for over ten minutes and gradually slows to a halt at the end. But I loved it so much at the time I really want to see it again. It may have been around 1993-4, but no later than Feb 1995, when I switched to PC for Doom ;)
I'd be grateful for any assistance in finding it.
I'd be grateful for any assistance in finding it.
where is that demoeffects list txt?
Optimus: it was taken down after cleanup.
i put it up again. here
i put it up again. here
Reporting what I've asked on CSDb forums:
I would know if there is an usual name related to the cheap and absolutely oldschool fake rastersplit effect you can see in a later loading time in Vector Overdose, or in the most famous Geggin's part of Wonderland VI, which is basically a DYCP.
In No Cooper, its author named it with the horrible definition of *gasp* "distorted rasters".
I would know if there is an usual name related to the cheap and absolutely oldschool fake rastersplit effect you can see in a later loading time in Vector Overdose, or in the most famous Geggin's part of Wonderland VI, which is basically a DYCP.
In No Cooper, its author named it with the horrible definition of *gasp* "distorted rasters".
Oops, the picture was:
