Demo Design - On the history demomeykinga.

<b>Demo Design</b> - On the history demomeykinga.
Topic: Demo design
Author: Realm of illusion
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DEMO.DESIGN .* Frequently Asked Questions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Contents:
---------
0. Few of demos, the history demomakin
g'a and traditions.
1. Terms of direct relevance to demomaking'y.
2. List of Demos / Intros / Diskmags, deserve to see them.
3. Tips and requests to (future) authors
demos / intros / diskmags.
4. Commodore 64 as the machine on which
was the beginning of demomaking'y.
5. A selection of some useful algorithms, and interesting 
solutions. 5.1.Realizatsii Fong.

---------------------------------------( C) Realm Of Illusion 
'1996-1997 


  0. Few of demos, demomaking'a history and traditions. [Peter 
Sobolev] 

  Often there are discussions about what
represents a perfect demo, that
in
It must prevail, and what should not
but being in general. Without claiming to be the truth
last resort would like to make a few theses, to which I came, 
simple lediv for a long time, the Commodore 64, Amiga, and now 
the PC demo scene 

  History has developed in such a way that
heyday demomaking'a on each of the
three listed vehicles slightly crossed. Roughly it looks like 
this: 

I. 1987 .. 90 - Commodore 64
II. 1988 .. 93 - Amiga
III. 1992 .. 96 - PC


  In the first period, in fact, began
demomaking, - all that was done - done
'For fun'. Demos release is not only
party but also just so - no connection with Kaki
Mi-or events. Lack fido / inter
net networks (and, consequently, - the impossibility of 
widespread source and tools'ov) introduces an element of 
originality in every demo. Using loggerheads effects considered 
a disgrace for the team. The style of this era demos

characterized by a large number
art elements (the original
fonts, drawing pictures, interesting
zadumok in the plot, a lot of different music in a single 
demo). By the end of an era when there were Amiga and PC people 
have been thinking about switching to more powerful machine. 
Because PC Then do not stand any competition, the choice of 
most of demomaker'ov fell on Amiga'y.



  Second Age-era heyday Amiga began with the fact that people 
began to use in their works the possibilities machine Ny, which 
was not in the C64. This is, first turn, the rate of iron, 
allowing represent the vector objects in the real

time, as well as more memory and
digital audio. Demos have acquired a new hue - they were often 
contain pure vector 3d and 2d of (among others), usually with 
the effects of well-synch ronizirovannymi with music.


  BBS craze has become widespread and people began to exchange 
information. In the present Noah has played a particular area 
is sharply negative role. Together with real

but good work was showing those
ndentsiya copy already in uvidennogo.Tut
intervened case - the company produces
Amiga'i was declared bankrupt and purchase
on ESCOM'om. Although it can not be called fatal, but it caused 
a failure of many firms maintain these machines, a sharp 
decrease in the volume of produced software and how 
Consequently, declining interest in Amigo. 

  Thus, some people began to think about
moving to another machine, which is not ka
salis such problems. This machine has become PC.

  The third period did demomaking massive enthusiasm. The 
emergence of VGA and SB gave a very strong push in this 
direction. And again, what could be done to

previous machine, steel implement
here. Now the winning factors are
were speed and memory. Since
in all other PC is hopelessly behind (and still is) on the 
Amiga, and often so same from the C64, then all the flaws in 
the iron complex pensate speed video / processor

All the same rate provoked demomaker'ov go entirely to the
3d effects, forgetting all about art, tradition and 
t.p.Blagodarya wide raspostranen particular PC, the mass of 
programmers' software for it, and most importantly, has 
embarked on its feet WAN - any man could reading the literature 
downloaded from BBS / FTP litter samples of different effects 
to blind them all together and unreleased demos. "Become 
demomaker ' om ... "This led to the appearance of giant

On the number is constantly appearing identical
tical demos are hard to even watch to the end, not what to get 
from their viewing pleasure. Party quickly

become a purely commercial event with cash prizes. Their 
quantitative began to grow in proportion to the number of 
demos. This flow of releases has become impossible to even see, 
not what estimate. Demos were released not on the party in

public rarely someone skachivalis.Dostatochno
look at ftp.cdrom.com / pub / demos,
to assess the extent and low quality
work.


  This is the situation abroad and the current day. Where will 
this lead can only to assume. Declining interest in demo

making'y will cause an outflow of "excess" of people and
theoretically, should cause a new wave
high-quality demos that will be produced by those for whom the 
interest is not the case tea, and permanent. Let's hope that

this happens:)
Somehow this situation, "they." There
some faint hope that we still have
able to avoid such a sad fate.
Although releases of demos in xUSSR not too often
Toe phenomenon, most of them is represented
exists an interesting work.

First and foremost it is worth noting that the demo
is primarily a work of art. Best indicator that the demo
success, is its success among people,
far away from programming. In this sense,
le seems to be very successful comparison demos
video clips (and me with AK Trinity:))
After all, clips are removed, based on an assessment
mass audience, rather than professionals.
Also in the demos - if you can see on the screen
not a nice effect, not if you care
how to do it? What is the difference written in the code xor 
ax, ax instead mov ax, 0 or not? Of course, not everything is 
the direct straight-line. For example a bad habit to use in 
demos so-called net animation (pure animation). In this

If the demo is no longer a combination of
talent of artists, musicians and programmers
ta-demo, consisting mainly of packaged recruitment is not a 
demo. On the other hand a reasonable combination of animation, 
along with the code is quite acceptable. 

========================================

1.Glossary
==========

Definitions given below, of course, are predominantly demo 
scene.V rate bkah are words which occurred ter

minutes, or another variant of the term.
 Musician (music artist) - musician, the person writing the 
music for demos, intros, music disks, etc.  Coder (code) - uh 
... programmer. In a rather narrow sense of the word - uses 
mostly assembler. 

Graphician (gfx artist) - artist, rice
em a picture, logo, fonts, etc.

Swapper (swap) - spread the word deals with the software (your 
group or not, it does not matter) through the regular 
(non-electronic) mail (Parcels, letters, etc.)


Fixer (fix)-fix deals with software to work correctly. For 
example corrects other people's bugs, ruled NTSC ' shny 
software for work in the car PAL'ovskoy (Commodore 64)


Organizer (organize) - organizer of ideas
LIMITED mastermind that Lee;) command.

Cracker (crack) - deals with burglary Sof
the one with the aim of deprotection / no restrictions
constraints.

Crew, Group - a team, a group of people united by the idea (or 
organizer) for implementation of any project (s) (eg writing, 
demos, hacking / raspostra equation software or anything else).


Demo (in general) - a program written with
to demonstrate the capabilities of the team in
programming, graphics, music and design.
Does not imply their purpose of extracting
profits.
More precisely:

Demo (demonstration) - larger than 100k

Intro (introduction) - the size of not more than

  100k. Can be divided into:


  1) Invitation intro - intro, written by
to invite people to any party. Contains a description of the 
conditions of competition, the equipment used, the timing, 
venue, etc. 

  2) BBS intro - an advertising BBS. Usually small in size, with
one way or another and the text and 1-2 effects and, sometimes, 
music (Often Adlib'ovskoy). Ctremyatsya stuff

in archives, going through the BBS.

  3) Crack intro - intro, written in
after hacking group / cracker 'om anything. On it you can say 
almost the same that of BBS intro.


  4) Intro-roughly speaking, a small demo.
This, for example, those intros, which are involved in 
competition'ax. Formally, the anything except size, of demo is 
different. 

Trackmo (TRACKING deMO) - on the PC / Amiga -
demo or intro, in which all the action
(Ie image) is rigidly tied to th
zyku such a way that looks at one go. Music - Techno usually 
(conveniently it just sync). On the Commodore 64 so called 
demo, which does not require a During a human intervention

(Pressing the space bar to continue, etc.)
Dentro (DEmo-INTRO) - demo preview.Vypyskaetsya to probydit 
interest in the demo which is not ready yet, but expected. Is 
sometimes just a set of pictures (Slideshow) with myzykoy and 
transfer effects, which can bydet yvidet in dem Re.

SlideShow - a picture (drawing or grains
Deren), shows (with music).

Music Disk - a set of several songs
musician / s group, beautifully decorated
images / effects / text.

Diskmag (Disk Magazine)-e zhurnal.Otlichaetsya from simple text 
file by the presence of music / graphics / any form 
deoeffektov. Ie appearance of the journal almost as important 
as its content.


Logo - small image (below screen), representing a symbol / 
emblem Therefore, anything. As a rule, the stylized

the name of the team or project.

Compo (competition) - contest / Comp
zanie / competition (see also the 'Party')

Party-organized with a view to
bunch of people. For example, demo parties -
to view the demos, which are often
written specifically for such events. Usually organizes a team
with the assistance of sponsors. The most frequently
parties are held in the Scandinavian countries. Of regularly 
passing demo party: Assembly (early August), TheParty 
(January), The Computer CrossRoads, Tribute, Camelot, etc. 
Traditionally demo par ties are conducted in the following 
types: 


  Demo competition - the maximum size

    4MB. Net animation (FLI'ki, etc.)

  prohibited.

  64k Intro competition - the maximum

    Size 64K

  4k Intro competition - Max size of 4K,

    Music is forbidden (ie, the sound will be

    off during playback)

  Graphics competition-the maximum time

    solution 640x480x256. Scanned, and

    also obtained with renderin

    ha (3ds, etc.) images is prohibited.


  4channel music competition \ 8channel
music competition / in one of the standard formats tipa.S3M,. 
MOD,. XM, .669,. STM etc.


Computer, usually used for the demonstration: P5-100, 4MB RAM, 
PCI VGA; Sound: SBPro or GUS.


HQ / WHQ / RHQ / ... (HeadQuarters, World Head
Quarters, Russian HeadQuarters) - "The staff
Apartment "(World / Russia / etc) are usually the main BBS 
komandy.Na her lie village glacial releases group through it 
can be attributed to zatsya with the group.

Distribution Site (dSite, DistSite) - BBS
(Ftp), where you can download all / recent releases command (s) 
dSite'om, which (S) of this BBS is.


X-modes (tweaked modes) - mode, which allows a standard VGA 
(VGA256K) and standard VGA monitor to get resolution higher 
standard (usually). Widely raspostraneny:



  320x240x256c (square point, 3 countries
    boundary)

  320x400x256c (2 pages and high times

    solution - a compromise)

  360x480x256c (this is the largest resolution
    of which can be achieved on a VGA

    at 256 colors)

256-color mode with a resolution of horizontal
zontali> 360 points to use has no
sense. They will not go at all VGA.
Profiles> 400 points can be obtained only
on SVGA cards. Unfortunately, at different
SVGA is done slightly differently.

  In all these cases it is sufficient
but the VGA monitor, and 256k Video RAM)
Gradient Filling (gradient fill) -
Shading circuit c smooth change of brightness / color.

Fractal (fractal, fractal) -


  1. Self-similar sets, which for
any increase in forms similar images
tion, most famous - Koch curve,
polygonal Sierpinski set Mandelbrot
Ta.


  2. Mandelbrot set, as the most
well-known special case in the theory of Julia sets. Described 
by the theory of functions of complex variable, n neriruetsya 
with the aid of an iterative process sa z (i) = z (i-1) * z 
(i-1) + c, where z-complex number, c-preselected constant For 
an arbitrary point in the plane with coordinates (x, y) takes a 
complex number z, where x - is real, and y - imaginary

imaginary part, we consider the behavior of this
sequence through enough pain
large number (n ~ 100-1000) iterations. On
plane drawn point (x, y) color
usually depends on | z (n) |.


  3. Any images / landscapes / images
for the formation of which use helium
generator of random numbers, such as: plasma, voxel landscapes 
... Although, by and large, it's all the same;)) 

Voxel (VOlume piXEL) - element of the space, volumetric pixel. 
Voxel technique involves partitioning the space into separate 
elements (usually tow parallel planes OXY, OXZ, OYZ) and 
viewing these elements as a indivisible.


Texture Mapping - a method the overlay / transparency / 
irregularities / etc on the surface, to impart realism.


Environment Mapping - overlay maps
(Map) environment leads to
that shiny (specular) objects
begin to reflect everything around them. When
Change position of an object, reflection
also changes, reinforcing this effect.

Bump map - map of the irregularities.
Glow map - map samosvetimosti, shine.
Motion Blur, Delayed Vectors - related concepts. In fact the 
effect of blurring images for (fast) movement. Delayed Vectors 
The term most often applied to WireFrame objects.


Fading - a smooth change in brightness (part of) the image. On 
the PC, as a rule, dos Tiga change R, G, B for a given

color palitre.Na C64 (and sometimes on the PC) attributes the 
change to this part of the image.


Shading (shadowing, shading) - Methods
allow to reproduce the object in time
nomu depending on the location of the source
nick lighting.
Facet (flat) shading - face polyhedra
ka are colored, each with one color
taking into account the orientation in space with respect
respect to the source and the observer.
The object looks like a crystal.
Gouraud shading (.. Guro) - Method Polutov
a new division with smooth color transitions
passages: for the corners of each polyhedron
assigned different colors, and then about
usual interpolation in the framework of their surface.
Phong shading (.. Phong) - a method of half-tone shading, which 
is held interpolation of the normal to the surface of many

gon, and then fill that creates the effect of the game color 
(highlights) and gives more more natural image than the method

Guro, but it works, usually slower than him.

Nix Shading (.. Nix'a) - this method-a kind Phong shading'a 
(method # 1 paragraph 5.1), and texture that is the table 
256x256. The only difference is that normal is not interpolated 
in the polar coordinates, but in general such that no name. 
This interpolation gives the same error, as in polar 
coordinates. But Nix solved the problem of rotation objects in 
all directions: to rotate normal in the Cartesian system, and 
converting to polar directly at shading.


Splines (Splines) - types of mathematical
models used to represent
smooth curves passing through given
point.

Scaling (zoom) - increase
or decrease (part of) an image or
object.

Shade Bobs - effect obtained when moving across the screen from 
an arbitrary trajectory theory of pattern (eg circle or square)

and at each point of movement, summing
color with the color already present in the pattern, ignoring 
overflow. It is noteworthy that, if we move in the opposite 
direction, but subtract color, then we back to black screen.

Wireframe - view images of models
stresses in the form of a "wire frame" of
connecting segments.

Zoom (in / out)-increase (zoom, zoom in) /
decrease (zoom out) object.

Aspect Ratio - the ratio of height to Shea
Reena physical pixels (or width to
height? I'm not sure). For the standard
monitor, the geometric dimensions of the screen
which are made by TV standards, ie with the ratio of 3:4, 
aspect ra tio equal to one will have modes

320x240, 640x480, 800x600, 1024x768,
1200x900, 1600x1200, etc. Respectively
for any monitor, and arbitrarily
th mode aspect ratio is as follows: AspectRatio: = Screen
Height / ScreenWidth * X_Resolution / Y_Reso
lution;

  where AspectRatio - required a.r.;

  ScreenHeight and ScreenWidth - height and

    width of the screen to see (or meters, mils

    limetrah, etc., so that in the main identical
    tical units);

  X_Resolution and Y_Resolution - respectively

    respectively for the mode in pixels.
Accordingly, when they say "a picture
has an aspect ratio N. NN ", it means that it will look like and
intended for display in mode ar equal N.NN. Finally, if you want
scaled image c aspect ratio
PictureAspectRatio equal to the normal display on a standard 
monitor (with about portions of 3:4) in a mode to X_Resolution

Y_Resolution pixels, you have to stretch it across the width 
(or shrink if the number less than one out) in X_Ratio: =

PictureAspectRatio * 3 / 4 * X_Resolution /
Y_Resolution; times.
Well, or Do the same with the height
(Not touching the width), making it 1/X_Ratio
times longer.

Transparency - transparency.

Transparent Vectors - the method of images
transparent object.

Morphing - smooth "transformation" of one
Object (image) to another through the mouth
update folder-one correspondence of each element of the 
original object (Image) is finite and smooth change to each 
druga.Morphing is a mixture of three separate algorithms:

warping'a, tweening'a and dissolving'a.

Warping - a mathematical trick, by which the image is stretched
and compressed, as if it were painted on
rubber. Warping is defined by points or lines.

Tweening, short for in-betweening, interpolation of two images 
for smoother animation. Tweening usual but it runs over the 
points, lines or poligonami.Tweening convenient to use,

if a particular implementation warping ori
ented to linii.Tweening 'th position
control lines can be continuously distort the picture. Even 
with just war ping'a and tweening'a, you can create 
photo-realistic animation of a single photo graphy.

Dissolving, or cross-dissolving, - so
talked about in Hollywood when a scene
obscured, while another "clarified." In the middle to do a 
double exponential zitsiya.



  Obtained as follows: if the whole image
cover the net, then warping changes the shape
Therefore, each quadrilateral, tweening
moving grid, and dissolving a piece of the picture changes 
within the quadrangle. When all these three effects are applied

together, it turns morphing.

Raytracing - a method of constructing a realistic image of an 
object by its geometric cubic (mathematical) model. For each 
picture element from the point of observation Denia pave the 
imaginary ray to determine, as part of the model should 
reproduce exhaust oneself to this point in the displee.Izza 
need for more computing is suitable mainly for obtaining static 
images (on machines of type Amiga, PC). Examples of programs 
that implement this method: Imagine (Amiga, PC), Caligari 
TrueSpace (Amiga, PC), RayDream, Pov Ray, Vivid. In 3D Studio 
This method does not used.


Rendering - creating images that
or other representation of the object with the use of
The use of one of the methods of synthesis of realistic images 
(eg, Raytracing, Gouraud Shading) (about surface, the bulk 
parameters, etc) 

Anti-aliasing - eliminating irregularities /
aliasing contour image.

Bump Mapping - a method of displaying bumpy surface.
Frame Buffer - specially allocated area of memory in which an 
image (picture) stored in a form ready for output to

screen.

S-Buffer - the same as the Z-Buffer,
only one image is taken not a single pixel, and a segment of a 
horizontal (or vertical, if so convenient) scan 
linii.Rasshifrovyvaetsya as Span-Buffer (sometimes called 
SegmentBuffer). Clipping - cutting off parts of the image

beyond the boundaries of the region.
Modeling - the process of describing the shape, object motion 
and structure of its surface. Sprite (sprite) - small (much

smaller than the screen) a graphic generated by hardware, which 
can be derived / move in any graphics / tech Stove mode. You 
can draw an analogy - seemed to have imposed a transparent 
screen film, which depicted risunok.Obych

but there are also a means for detecting the collision sprite 
(sprite to spri te collision), the collision sprite with iso

by the mapping (sprite to background collision), the sprite can 
also be placed before or images or other sprite

(Sprite priority). In most systems,
there is a limit on the number of sprites that are visible on 
the screen simultaneously. This limitation, as a rule, can be 
overcome. About domain of application: moving objects at

position of one image to another, an increase
An increase in resolution / number of flowers every
mapping, scrolling. What is called
sprites on the PC - have in common with them
only that it is too small graphical
cue object:) Really, is it just a picture. All the above 
features are implemented in software and because of this 
poorly.  Animation (Animation) - Serial

display stored in the memory / disk packed / not packed images.
(Standard format - is, for example,
. FLI,. FLC,. AVI,. MPEG). If the image
formed before appear on the
screen (by any calculations, or simply from other images)
then, as a rule, it is not animation.