Cool Things in Small Spaces

1
Cool Things in Small Spaces

• The Art and Science of
• Intros and Bytetros

2
Who am I?

• I am Polaris, the founder of the Northern
  Dragons Demo Group. http//www.northerndragons.ca
• I am also an active coder for the Northern
  Dragons and have written code for several 4kb
  productions. The most recent being 4kb
  Evolutio released at Assembly 2004.
• Yes, you can contact me just email me!
  polaris_at_northerndragons.ca

3
What are we supposed to talk about?

• Showcase some example intros and bytetros.
• Highlight whats special about intros compared to
  demos and their role in the demo scene.
• Tell some Tales from the field
• Design advice
• Code techniques - specific to Windows 32
• Your requests, and questions are important!
• There is a 15 minute period for questions at the
  end, but do ask questions during the presentation
  too!

4
What am I not talking about?

• Intros larger than 16kb, in terms of techniques.
  (64kbs are quite different)
• How to use any particular intro creation tools
  such as .werkkzeug1
• Things outside of the win32 platform. (Outside my
  realm of expertise)
• API wars. (For example OpenGL vrs Direct 3D)

5
What do you want me to talk about?

• The seminar is in a Power Point can, but Im
  flexible!
• Room Survey (show hands)
• How many people are here are active in the demo
  scene?
• How many people are actively writing productions?
  
• What roles? (Coder?) (Musician?) (Artist?)
• What platform? (Win32? Linux? Other?)
• Does anyone have specific things in mind they
  want answered during the presentation?

6
What are Intros?

• The first intros were cracktros. These
  programs are graphical brag tags, that appeared
  at the start of a cracked games. These gave
  greetings to other crackers, and displayed the
  credits of the crack authors using pseudonyms.
• Eventually, people started making little
  graphical programs for fun, instead of just in
  cracks. This gave birth the demo scene in
  general. Demos are real-time computer
  productions of a larger size (typically MB now),
  where as intros are limited size.

7
Why make them?

• Intros explore the technical edge of whats
  possible in a small space, as well as exploring
  real-time art.
• Each one is a personal brag tag saying look what
  we can do!
• Every intro is really an experiment showing
  apparently this is possible in xxxx bytes
  whatever the size is.
• Still, some intros have more spirit and design
  than others.

8
King of the Kings Demo Parties

• Demos and intros are often shown at parties,
  Compos (competitions) where they compete for the
  audience favor and prizes.
• Pilgrimage is one of many events where compos are
  held.
• Competitions help spur intro creators on, to
  out do each other.
• There will probably be some intros released at
  Pilgrimage -)

9
What does a small intro look like?

• Lets watch some samples.
• The following samples just a few I have chosen,
  so be sure to check out demo scene sites for
  more
• www.pouet.net
• www.scene.org
• www.256b.com
• These productions have been released at demo
  parties, so please rank your favorites as you
  watch. Well compare your ranking to the party
  ranking after.

10
4KB Intro Viewing Order

• 1. San Angeles Observation
• http//www.pouet.net/prod.php?which13020
• 2. Smells Like Fish
• http//www.pouet.net/prod.php?which13075
• 3. Evolutio
• http//www.pouet.net/prod.php?which13073
• 4. 99 Beers
• http//www.pouet.net/prod.php?which10564
• 5. The Etherium
• http//www.pouet.net/prod.php?which10569

11
256 Bytetro Viewing Order

• Dropz
• http//www.pouet.net/prod.php?which4015
• Tube
• http//www.pouet.net/prod.php?which3397

12
Lets Watch!
13
San Angeles Observation by Armada Trauma

• Release date August 2004
• Party Assembly 2004
• Ranked 1st

14
Smells Like Fish by Axes Denied

• Release date August 2004
• Party Assembly 2004
• Ranked 8th

15
Evolutio by the Northern Dragons

• Release date August 2004
• Party Assembly 2004
• Ranked 4th

16
99 beers by Siffo

• Release date August 2003
• Party Assembly 2003
• Ranked 9th

17
The Etherium by The Northern Dragons

• Release date August 2003
• Party Assembly 2003
• Ranked 14th

18
Dropz by Baze / 3SC

• Release date 1998
• Party Demo Bit 1998
• Ranked 1st

19
Tubes by 3SC

• Release date August 2001
• Party Syndeecate 2001
• Ranked 1st

20
Surprised by the Rankings?

• Intros have evolved from just pushing technical
  limits, to having a sense of design, and
  appealing to the audience.
• The importance of Design is discussed well in
  Tips for Demomakers
• http//www.theparty.dk/pages/scene/tips_for_demoma
  kers_a_story_to_tell.html
• Also check out the 4KB intro compo studio from
  assembly for some discussion about design.
• ftp//ftp.scene.org/pub/parties/2004/assembly04/as
  semblytv/4k_intro_compostudio.aviid250850

21
So you want to create an intro? (Technical Notes)

• Intros typically feature real-time music and
  graphical effects.
• Because of the small space, data isnt typically
  stored. Instead algorithms that generate the
  data have to be used.
• The most important thing about writing an intro
  isnt the platform, or coder tricks. Its about
  the algorithms in the first place.

22
A simple example texture

• The texture on the right is 256x256, with 0-255
  in colour grey scale.
• Even as a .jpg with compression it takes a
  total of 6KB to store. This is larger than many
  intros!

23
Using algorithms (Example)

• To generate our texture, we instead need to use
  an algorithm. This un-optimized algorithm
  generates this texture
• for(y0y lt 256y)
• for(x0x lt 256 x)
• // the algo
• height_value(1-(sqrt(((x-128)(x-128))((y-128)
  (y-128)))/128))255
• Note even without code size optimizations, it
  takes no more than 200 bytes in a basic C
  compiler a savings of over 15 Times!
• This is only a small example you need to think
  algorithmically about, textures, geometry, music,
  and code!

24
Programming Tools

• Once you start thinking algorithmically, it
  becomes time to code.
• Your intro or bytetro will eventually become an
  executable program, running on a pc.
• This usually involves an assembler or compiler of
  some type, to generate the binary code executed.
  For many this is assembly. but.

25
Language Examples

• Java. Yes its possible! Jar file with J3D
• Material Demo - 2,078 bytes
• Turbo Pascal
• Gargaj/Ümlaüt Design Hugi 22
• http//www.hugi.scene.org/main.php?pagehugi22
• Delphi
• Migeel Hugi 28
• http//www.hugi.scene.org/main.php?pagehugi28

26
Language Examples

• C/C
• Kwak by Calodox, 7th place Assembly 2002
• http//www.pouet.net/prod.php?which7105
• Evolutio by Northern Dragons, 4th Place Assembly
  2002
• http//www.pouet.net/prod.php?which13073
• Assembly Language
• The Etherium (NASM)
• http//www.pouet.net/prod.php?which10569
• Trees (MASM)
• http//www.pouet.net/prod.php?which9311
• Others
• Of course. Use your imagination!

27
Pushing the technical limits

• The first stage is to push the limit of the
  algorithm.
• The second stage is to push the limit of the
  Language selection. (A compiler or assembler)
• While many avoid Assembly language, it gives you
  the most options and flexibility to push
  limits. This may involve using features in
  ways they werent first designed. It isnt the
  only option however!
• The third stage is to push the limit of the
  operating system itself. This deals with OS
  limitations, or what a executable file is on
  that Operating system.

28
Second Stage Specific to C/C

• The largest changes possible relate to setting
  your compiler options, and how you code in your
  C/C compiler.
• Take the following example
• include ltwindows.hgt
• __stdcall WinMain(HINSTANCE hInstance, HINSTANCE
  hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
• MessageBox(0,Silly example",test!",MB_OK)ret
  urn 0
• This example, when compiled with default VC
  6.0 options results in a 24 KB EXE! ?

29
Tweaking VC

• The same program, altered just a little bit.
  Becomes 1KB in size!
• pragma comment(linker,"/ENTRYmain")pragma
  comment(linker,"/MERGE.rdata.data")pragma
  comment(linker,"/MERGE.text.data")pragma
  comment(linker,"/IGNORE4078")pragma
  comment(linker,"/OPTNOWIN98")include
  ltwindows.hgtvoid main()MessageBox(0,"test","te
  st",MB_OK)

30
What happened?

• Its the same program, but weve changed the
  compiler options, cutting out the fluff that
  the compiler includes by default. These include
• Microsoft Visual C Runtime Library
• 4kb section alignment not required
• Merged sections in the exe
• .text (default code section),
• .rdata (default read-only data section)
• .data (initial data section)

31
Pushing the Operating System

• The biggest challenge is the exe alignment, and
  headers. Windows 32 programs have a lot of extra
  fluff in them, that you dont need.
• The MS-DOS had a light program. This way it
  supported two types of programs
• .COM files - limited to 64kb, but no headers!
• .EXE files - for large exe
• For this reason most bytetros are actually MS-DOS
  .COM file programs.

32
Phase 1 Using an executable packer

• Because of the extra stuff in the exe header,
  coders started using executable packers.
• For details on the win32 PE format
• http//win32assembly.online.fr/pe-tut1.html
• Executable packers store the original exe using
  compression, and attach a decompression routine
  that writes the it exe to memory and then
  executes.
• A good standard exe packer is UPX
• http//upx.sourceforge.net/

33
Phase 2 Using a file dropper

• The problem is, the resulting compressed exe is
  still a windows program. It has a certain amount
  of fluff that you still cant avoid.
• To get around this, a technique known as file
  dropping was developed.

34
File Dropping

• File dropping takes a Windows executable program
  and attaches it to a MS-DOS .com file.
• This .com file writes out the attached windows
  executable to disk, runs it, and then deletes it
  once finished.
• Because this accesses the local disk for the
  temporary file, this technique drops a file.
• Be careful! Various parties have various rules.
  Some outlaw writing anything to disk!

35
File Dropping

• The write to disk routine takes a few bytes on
  top of the regular windows executable.
• The improvement comes from using a .com file
  packer. This is like a regular exe packer, but
  for the MS-DOS platform. A very good and
  popular one is apack.
• http//www.ibsensoftware.com/
• This technique is characterized by a MS-DOS
  window that shows up before the production
  starts.
• With this technique its possible for a 16kb to
  shrink down to 4kb. For Example the Etherium
  16474 bytes -gt 4008 bytes

36
File Dropper Tool Links

• A few Tools to create file droppers
• PE2EXE aka PE2COM From Frankie / Smash
  Designs
• http//www.active-web.cc/html/research/
• GEM Dropper 1.0
• http//gem.intro.hu/main01.htm
• Warning Many tools drop a file into C\. This
  may mean your production wont work on Windows XP
  post SP1, without administrator privileges.
  Read your tool documentation. (Or make your
  own!)

37
Phase 3 Cab Dropping

• No matter how you slice it a file dropper must
  have the executable code to decompress the
  original windows exe to disk.
• In Hugi 28, Gem Introduced a technique called
  CAB dropping. Since then this has become the
  defacto standard for 4kbs, most of the entries
  in Assembly 2004 4kb Intro Compo are cab droppers
  of some type.

38
Cab Dropping

• A cab dropper uses the operating systems extract
  program to decompress the exe. Cab files are
  similar to zip files.
• Win95/98/ME c\windows\command\extract.exe
• WinNT/2K/XP c\windows\system32\extrac32.exe
• To do the decompression you write a batch file
• It calls extract.exe, and or extrac32
• runs the win32 program,
• then deletes it.

39
Cab Dropping OS Dependencies

• Because of platform variations, often a cab
  dropper will call both extract and extract32.
  One works. The other results in something like
• 'extract' is not recognized as an internal or
  external command,operable program or batch file.
• For this reason some feel that cab dropping is
  messy.

40
Cab Dropping A single file

• Its also possible to trick the cab file format
  into having the batch file commands in it. This
  results in a single .bat or .cmd, that contains
  your production. Its possible to avoid problems
  with root folder writing by writing to the
  operating system temp folder.
• The joined cab / batch file has more info that
  shows up in the header. Specifically
• 'MSCF' is not recognized as an internal or
  external command, operable program or batch file.

41
Space savings / Tool Links

• In summary (The Etherium)
• 16474 bytes pure windows exe
• 4008 bytes as a file dropper
• 3856 byte as a cab .bat file
• Cab Dropper tool links
• Gem Cab Dropper
• http//gem.intro.hu/main01.htm
• 20to4 Cab Dropper
• http//www.20to4.net/

42
The Future

• As operating systems add features, new options
  become available for creative programming.
• In the future we can look forward to a variety of
  more cool things in small spaces! (on every type
  of operating system)

43
The Future

• The key is to be creative in the way you use your
  computer!
• Algorithm
• Code
• Operating System
• And DESIGN!

44
Question Period / Discussions

• Any questions?