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Heaven
Account closed
Registered: Jul 2008
Posts: 102 |
Rotating City with EOR
Hi guys,
I am from the evil side but some of you might know me from IRC or formatwar.net.
One of my dreams since Amiga days was to code a nice 3d rotating city landscape like this:
http://www.youtube.com/watch?v=wDzw_5apRiM
5:20 ff.
I went into the code there and there is not much magic going on except that the whole rotation is precalculated. the draw routine is only drawing the top of the skyscrapers and then it is drawn down via long unrolled EOR code block.
the Zoom in and zoom out is precalculated, too.
Any c64 examples of such an effect and how are you doing that? charmode? multiplexed sprites?
thanks for any thoughts and suggestions.
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Oswald
Registered: Apr 2002
Posts: 5094 |
That's a pretty cool atari demo I havent seen yet. Also funny to see it was the source of two effects in Reflex demos. (BOB part, and fading out text.)
I have made this in Soiled Legacy, but only using 2 colors. My tricks were:
a) X expanded sprites to halve the drawing area
b) repeating char row at the bottom because the bottom is the same vertically.
You can use trick b) easily with a repeting DLI. Cool thing would be to do it in realtime, with clever thinking there's not much to calculate, the only problem would be clipping. |
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Heaven
Account closed
Registered: Jul 2008
Posts: 102 |
Oswald, which Reflex demo? found many on youtube ;)
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Heaven
Account closed
Registered: Jul 2008
Posts: 102 |
and your City was it precalculated like hell, too? you have zooms, too.
on A8 you could do it with nice DLI stuff and spice it up.
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Oswald
Registered: Apr 2002
Posts: 5094 |
1:50
http://www.youtube.com/watch?v=2Ei2cBJa6tE
3:41
http://www.youtube.com/watch?v=UrgExLcjAuo
yep, mine was precalculated too, there were to anim sequences, one going around the city, and one flying trough it. they could be mixed, so you could do 2 fly arounds, and then one go trough, etc. This was not used tho, cause then the part would have lasted too long. |
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T.M.R
Account closed
Registered: Dec 2001
Posts: 749 |
Quoting OswaldThat's a pretty cool atari demo I havent seen yet. Also funny to see it was the source of two effects in Reflex demos. (BOB part, and fading out text.)
Might want to check the release dates, unless Fandal's site is wrong Total Daze came out in 1997 and i don't even have to look to know Radio Napalm was 1995. =-)
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Heaven
Account closed
Registered: Jul 2008
Posts: 102 |
yeah. Greetings look "inspired" ;)
but at least in Total Daze it was used while loading the next part ;)
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Oswald
Registered: Apr 2002
Posts: 5094 |
Quote: yeah. Greetings look "inspired" ;)
but at least in Total Daze it was used while loading the next part ;)
my mistake. But many other rfx stuff was coming from A8 if I'm not wrong. |
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Heaven
Account closed
Registered: Jul 2008
Posts: 102 |
Oswald. any clue how I can precalc the City easily with small 3d knowledge?
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Skate
Registered: Jul 2003
Posts: 494 |
@Heaven: of course you can choose real 3d path (which would be more accurate and still simple enough) but since you mentioned your lack of 3d knowledge, you can easily calculate that kind of vector city using sin and cos only. think about the vertices, they are all rotating on an elliptic orbit. you vertices have three parameters (y,r,sa). y is the height which effects vertical movement and position, r is the radius and sa is startup angle. what extra you need is to sort vertices by z index. this can be done using radius and rotation angle parameters. start thinking on ellipses and it will come to you. :)
you may need more than one origin, keep that in mind. |
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Heaven
Account closed
Registered: Jul 2008
Posts: 102 |
@Skate
thanks. I have done a basic version of wire frame city and the skyscrapers rotated on 64 byte elipses tables based on.
deg
c=0
for i=0 to 359 step 360/64
x1=mx+sin(i)*rx
y1=my+cos(i)*ry
xtab(c)=x1
ytab(c)=y1
c=c+1
next i
and my first attempts to do the city in 3d (including projection, transformation etc) in realtime was out of question as my polyfiller made the whole scene look like a slide show ;)
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