Windows Tiny Intro
Contents
Introduction
This category is for the tiniest Windows / win32 intros, that often use custom Windows PE header in combination with a minimal shader setup or CPU software rendering.
Tools
- Assembler: NASM ( https://nasm.us/ )
- Optional : PPEE ( https://www.mzrst.com/ ) Professional PE file Explorer
Re-using Windows Header
The minimum Windows PE Header size on modern systems (Windows7 and up) is 268 bytes, even though part of this header is useless padding. So whilst it is perfectly possible to do a small graphical effect within thatn 268 byte limit by re-using part of the header, doing anything smaller than this lower limit is only possible on older Windows versions like Windows XP.
PE Header Structure
Here is the windows header structure:
ORG 0x400000
base:
DW 'MZ' ; 00. e_magic
DW 0 ; 02. e_cblp ; UNUSED
DD 'PE' ; 04. Signature
; COFF header
DW 014CH ; 08. Target Machine (Intel 386)
DW 0 ; 0A. NumberOfSections (use 1 for overlapping section)
DW 0,0 ; 0C. TimeDateStamp ; UNUSED
DW 0,0 ; 10. PointerToSymbolTable ; UNUSED
DW 0,0 ; 14. NumberOfSymbols ; UNUSED
DW 8 ; 18. Size Of Optional Header
DW 2 ; 1A. Characteristics (2 = IMAGE_FILE_EXECUTABLE_IMAGE)
; Optional header
DW 010BH ; 1C. Magic (PE32 32bit EXE)
DW 0 ; 1E. Major+MinorLinkerVersion ; UNUSED
DW 0,0 ; 20. SizeOfCode ; UNUSED
DW 0,0 ; 24. SizeOfInitializedData ; UNUSED
DW 0,0 ; 28. SizeOfUninitializedData ; UNUSED
DD start-base ; 2C. AddressOfEntryPoint
DD 0 ; 30. BaseOfCode ; UNUSED
DD 0 ; 34. BaseOfData ; UNUSED
; Windows specific fields
DD base ; 38. ImageBase
DD 4 ; 3C. SectionAlignment (.e_lfanew / PE offset +4)
DD 4 ; 40. FileAlignment
DD 0 ; 44. Major+MinorOperatingSystemVersion ; UNUSED
DD 0 ; 48. Major+MinorImageVersion ; UNUSED
DW 4 ; 4C. MajorSubsystemVersion ; (use 3 of 4)
DW 0 ; 4E. MinorSubsystemVersion ; UNUSED
DD 0 ; 50. Win32VersionValue ; UNUSED
DD 0 ; 54. SizeOfImage (malloc) ; UNUSED
DD 30H ; 58. SizeOfHeaders
DD 0 ; 5C. CheckSum ; UNUSED/UNCHECKED
DW 2 ; 60. Subsystem (Win32 GUI)
DW 0 ; 62. DllCharacteristics
; 64. SizeOfStackReserve (program entry)
start:
; Program entry
; Padding to 268 bytes (minimal exe file length for Win7+)
Importing Functions
An important part of doing your own Windows Header management is that you will need to import functions manually. This can be done via header import, Import by Ordinal (specific to a windows version) or Import by hash.
Minimal Required Function imports
Here is a list for minimal function imports for any graphical intro.
-
LoadLibraryA- Required to load libraries -
GetAsyncKeyState(VK_ESCAPE)- Check for escape key -
ExitProcess(0)- Close down application
Optional Function imports
-
hwnd = CreateWindow((LPCSTR)0xC018, 0, WS_POPUP | WS_VISIBLE | WS_MAXIMIZE, 0, 0, 0, 0, 0, 0, 0, 0)- Set up a Maximised Window -
t=GetTickCount()- Optional: Get Current ticks -
ShowCursor(NULL)- Optional: Hide mousecursor
Graphics
For 512 bytes, there are 2 ways to go about rendering graphics:
Minimal OpenGL/GLSL Rendering
See http://www.sizecoding.org/wiki/1K_Intro for more information and setup
CPU Software Rendering
The following function imports are needed for software rendering:
- GetHDC
- GetWindowRect
- StretchDIBits
- SwapBuffers
Or for the slower on-screen approach:
- SetPixel
Sound
There are a few ways to producing sound/music in Tiny Windows Intros.
Win32 Single Note MIDI
Using the built-in MIDI, this requires just 2 calls
-
midiOutOpen(midihandle, 0,0,0,0)- To initialise the MIDI -
midiOutShortMsg(midihandle, 0x209035C0)- 4 byte Midi message that sets instrument + plays a single note on channel 0
For a full list of Midi commands, check out this webpage: https://computermusicresource.com/MIDI.Commands.html
Win32 MIDI Player
Depending on the sound budget, you can think about including a small MIDI tune instead. Similar to the single note MIDI approach, but playing multiple notes from data on 1 or more different channels.
Bytebeat softsynth
An alternative option is to use a very simple Bytebeat softsynth (Check out https://bytebeat.demozoo.org if you are not familiar with the concept).
The cheapest way to do this is to reserve and setup a 44 byte WAV header and precalculate the bytebeat music,
and then use the sndPlaySoundA call to play it as a looping sample at startup.
For a taste of what is possible with small (<256 character) bytebeats formulas, check out one of the Bytebeat Music competitions from the Lovebyte parties, for example https://demozoo.org/parties/4760/#competition_18623
Compression
Compression for the smaller Windows Tiny Intros are tricky, but there have been some experiments using the Windows Cabinet Decompressor calls
These functions allow for MSZIP (deflate) and MSLZ content to be loaded from the binary as payload at the cost of a a few more win32 function imports. Well this might be a good solution for 512 byte intros, the tipping point for Crinkler compression at the moment lies at the 800-850 bytes mark give or take.
From cabinet library:
-
CreateDecompressor(0x20000002, 0, &HDecompressor)- Create Decompressor object -
Decompress(HDecompressor, CompressedPayload, PackOutputSize, 0x11000, PackInputSize,0)- Decompress payload
512 byte intros for Windows
- New Ground (2019)
- The Grid by Tomcat (2019)
- The Hole by Tomcat (2019)
- Spherical by MX/Addict (2023)
- (R)evolution by MX/Addict (2024)
- Mixontil by Busy (2024)
256 / 268 byte intros for Windows
PE Header Resources
- Tiny PE header information
- Overview of PE File Format
- LUEVELSMEYER’s description about PE file format
- Article about Making a 874 byte Windows EXE
- Another Tiny PE Header with information
Seminars
- Ideas and Techniques for Smaller Executables Seminar Video
- Ideas and Techniques for Smaller Executables Seminar Slides
