1K Intro
Contents
Introduction
This category is dedicated to 1K Intros for Windows 32.
Windows 1K Intros can be setup in C or Aseembler, or a combination of both, with only the few windows calls that are used being linked in. In general writing everything in assembler should give you a little more freedom in pushing/popping your function arguments and register usage, but in the past quality intros have been written in both languages.
Graphics are usualy done using OpenGL / GLSL, but there are 1K intros out there that have used D3D/DX11 instead.
Tools
There are a couple of options for tools, but general these tools are often used
- Visual Studio / Vscode / GCC Compiler
- Crinkler or other external packer for compression
- Optional / Alternatively: NASM Assembler
- Optional: Local/Online GLSL Shader editing environment (e.g. Shadertoy, Kodelife, bonzo, etc.)
- Optional: Shader minifier
Minimal intro code
Here is a step by step breakdown of what a minimal intro/framework should contain.
As a general rule of thumb: The less functions you need to use/import, the more space you have for your effect and data.
Setup (Windows)
-
ChangeDisplaySettings(&screenSettings, CDS_FULLSCREEN)- Initialise fullscreen view -
hwnd = CreateWindow((LPCSTR)0xC018, 0, WS_POPUP | WS_VISIBLE | WS_MAXIMIZE, 0, 0, 0, 0, 0, 0, 0, 0)- Setting up a Maximised Window -
hdc = GetDC(hwnd)- Get DeviceContext handle -
ChoosePixelFormat(hdc, &pfd)- Set pixelformat describer by pfd to DeviceContext handle -
ShowCursor(NULL)- Hide mousecursor (usually required by compo rules)
Setup (OpenGL)
-
glContext = wglCreateContext(hdc)- Create OpenGL context -
wglMakeCurrent(hdc, glContext)- Set OpenGL Context -
shaderProgam = glCreateShaderProgramv(GL_FRAGMENT_SHADER, 1, &shader)- Create and compile GLSL Shader -
glUseProgram(shaderProgram)- Set active shader
Update Loop
-
t = GetTickCount()- Optional: Get Current ticks -
glColor3us(t,0,0) / glColor3i(t,0,0)- Parse time via gl_Color (saves importing uniform functions) -
glRects(-1,-1,1,1) / glRecti(-1,-1,1,1)- Draw a single quad with current Shader -
SwapBuffers(hDC)- Swap Buffers -
PeekMessageA(0, 0, 0, 0, PM_REMOVE)- Optional: Unanswered messages might stack up, but in practice you should be fine in fullscreen -
GetAsyncKeyState(VK_ESCAPE)- Checks for escape key (required by compo rules)
Closedown
-
ExitProcess(0)- Close down application
Graphics / Effect
As far as i am aware of, most if not all 1K Windows intros use a single-stage shader setup to run everything. This means that everything including timing, shading, progression, etc. needs to happen in a single GLSL/HLSL shader and are often based on a single effect, with some changes over time.
So when it comes to writing your 1K Shader/Effect, there are a couple to tricks you can utilise to get a small shader footprint.
- Make use of the benefits of (Legacy) Desktop GLSL by using integers for smaller notation
- Make use of the fixed resolution to convert gl_FragCoord to UV -1..1 (this will have your centerY slightly off-centered)
- Pass time via glColor (no uniforms used)
- Using global variables to save space
Minimal GLSL example code
float t=gl_Color.x*1e7;
void main(){
vec2 p=gl_FragCoord.xy/960-1;
gl_FragColor=vec4(sin(p.x+t),0,p.y,1);
}
Shader minifier
While a shader minifier can be helpful at times, it will not save you from writing sloppy code or unthoughtful approaches. For most 4k's people can get away with sub-par optimised code and let shader-minifier do the work for you, but for 1k this is just not enough.
Sound
- Win32 Single Note MIDI
- Win32 MIDI player
- Bytebeat softsynth
- Shader softsynth
Compression
Microsoft Cabinet decompression
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, PakOutputSize, 0x11000, PakInputSize,0) - Decompress payload
Crinkler
Crinkler is the most commonly used compression at the moment for many 1K and 4K intros.
It has a seperate settings for 1K intro, namely /TINYIMPORT and /TINYHEADER which will better match the 1K usecase.
Crinkler reports
When using the /REPORT:intro_report.html feature, crinkler will generate a report and heatmap for your intro binary.
This is helpful to see how good your (shader)code compresses and where you can maybe gain a few more bytes.
Word about the resulting executable
Please note that when using crinkler in TINYHEADER mode, the resulting windows header will most likely trigger virus scanners / microsoft defender and mark it as suspicious content, which is a side-effect in recent years. Just exclude your work directory from this scan during development. Compo machines will run without these scanners too, but it is good practice to include a (slightly larger) safe version too in the final archive.
