Difference between revisions of "1K Intro"

Revision as of 05:42, 12 April 2024

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.

Frameworks

• IQ's 1k/4k frameworks
• hitchhikr's 1k framework
• Psycho's 1k/4k framework
• Audl's 1k framework

1K intros for Windows

• TBA