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EnigmA Amiga Run 1998 July
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EnigmA AMIGA RUN 29 (1998)(G.R. Edizioni)(IT)[!][issue 1998-07 & 08].iso
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Bump_mapping
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1998-05-31
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Date: Thu, 14 May 1998 13:12:29 GMT+1
From: Bojan Petrovic <BP12197D@ELAB.TMF.BG.AC.YU>
Organization: Tehnolosko-metalurski fakultet
Subject: [IML] QUEST: Bump mapping
Hello everyone,
I'm having a problem with altitude mapping (Im 4.0 DOS).
I create a bitmap, 100X100 pixels with a black background
and a white circle with fuzzy edges in the middle. (like
a one mouse click with an airbrush tool in some paint program)
Than i map this brush to a plane, scale it down 10 times,
and check repeat button so i have 10X10 copies on a 100X100
unit plane. When i use colour mapping everything looks just
fine, but when i switch to altitude mapping, no matter of
the y axis size (altitude), i get an ugly ...gap between
every copy of the brushmap. (it looks like a grate).
Date: Fri, 15 May 1998 02:05:14 +0200
From: Mikael Johannesen <mikael@PIP.DKNET.DK>
its a bug in Imagine for Dos, it has been fixed in IFW
Date: Thu, 14 May 1998 22:59:51 +0400
From: Charles Blaquiere <blaq@INTERLOG.COM>
It's a bug that was finally corrected in IFW. In the meantime, here is
something you may try; I vaguely remember that it worked. Draw your
repeating brushmap on a medium grey background, either (127,127,127) or
(128,128,128). This is the same value added by Imagine on the edges of a
repeating altitude brushmap, so it should make the grid-like border
disappear.
I think that Imagine uses some kind of interpolation
in altitude mapping (visible when i map a brush
that has something with sharp edges on it (e.g. just a plain
circle with no fuzzy edges). I wonder if this could be the
problem or am i doing something terribly wrong?
Date: Thu, 14 May 1998 22:59:51 +0400
From: Charles Blaquiere <blaq@INTERLOG.COM>
By the way, regardless which version of Imagine you use, you must always
ensure that altitude brushmaps don't have sharp changes, or they'll
propagate ugly streaks across flat areas. If you must have, say, a sharp
logo, scale the brushmap resolution to 2x or 3x; the anti-aliasing
introduced by your paint program will remove those sharp transitions.
However, since the map's axis size in Imagine will remain the same, it
will render with similarly-sharp contours.
One more question please.
When i make a bone object (let's say it's a tube with one joint
in the middle (like a human arm with no hand) and when i
rotate the mid axis 90 deg. (like bending your arm) and
make a state out of it, do i have to make so many
inbetween states so that the points would not move
just linear when morphing. (I have a feeling that
this was asked a xillion times, but I'm new to the IML)
I would be very grateful if anyone could help me with this.
I saw the particle fx requests and i think that it would
be great to make them independent, i think that
this is just a matter of linking them to the world, not the
parent coordinates when they are emitted.
As for the lens flare, i think it would be nice to implement
something like a bright horizontal or vertical strip of
light with variable intensity (you have all probably
seen it, sometimes when a rocket is launched, on
the place of the engine exhaust and a brightness
hotspot there is a glow and a strip that extends almost
to the screen limits. And it glows with variable
strength. I haven't seen ordinary lens flares in the shot, just
a glow around the engine and a strip.) I think that this could
be done with textures but it's just a proposition.
Thanks.
----------------------------------
Date: Thu, 14 May 1998 22:59:51 +0400
From: Charles Blaquiere <blaq@INTERLOG.COM>
Yes, you could take a transparent disc to which some glow-type textures
have been added, create a state, tack the textures to this state, then
stretch it 20 times in X or Z and create a new state. Use the stretched
state in your animation, moving in unison with the rocket exhaust but
tracking the camera. Glow objects don't have to be round!
----------------------------------
Date: Sat, 16 May 1998 19:18:24 +0100
From: Matthew O'Neill <mash@DINGNET.DEMON.CO.UK>
Organization: Spectrum
I do belive that I've found out how to get past the bumpmap bug
whichjust gives you the outline of it. Simply rotate the axis so that
Y faces the direction that you want to apply the map. This has fixed
about the problem about 90% of the time.
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