Fractal Forge

Open the web preview  ·  Get the Android app  ·  Build locally

Fractal Forge is an open-source Flutter explorer for mathematical systems and generative art. Browse 965 production fractals, tune parameters in real time, move through deep-zoom render paths, and export the views worth keeping.

See it in motion

The loop and catalog grid are browser smoke evidence, not a claim of full web/app parity. Export, sharing, CPU precision, and hardware GPU behavior are most complete in the installable app; see the renderer backend matrix.

What makes it useful

• Broad mathematical range — 965 production fractals across escape-time formulas, root-finding basins, strange attractors, IFS, cellular systems, tilings, space-filling curves, and ray-marched 3D forms.
• GPU-first interaction — Flutter fragment shaders keep ordinary exploration responsive, with deeper preview and CPU paths where the module supports them.
• A real creative toolset — presets, randomizer, looper, auto-explore, dual Mandelbrot/Julia viewing, wallpaper tools, sharing, and Fractal Music experiments.
• Color as a first-class control — 60+ color schemes plus smooth coloring, orbit traps, distance estimation, stripe and curvature averaging, and normal-map relief.
• Private by design — no ads, tracking, account requirement, or data collection.
• Accessible controls — high contrast, reduced motion, screen-reader labels, and configurable touch targets.

Explore the catalog

Family	Examples
Escape-time	Mandelbrot, Julia, Burning Ship, Tricorn, Celtic, Buffalo, Nova, Phoenix, Lyapunov
Root finding	Newton, Halley, Householder, Schroeder, Traub–Ostrowski, Noor Newton
Attractors	Clifford, Peter de Jong, Lorenz, Rössler, Aizawa, Dadras, Sprott, Svensson
IFS and geometry	Sierpiński, Koch, Barnsley Fern, Hilbert, Peano, Gosper, circle inversion
Cellular and number systems	Wolfram rules, Life-like families, Langton systems, Wireworld, Farey and Ulam views
3D and hypercomplex	Mandelbulb, Mandelbox, pseudo-Kleinian, quaternion Julia, KIFS

The catalog counts stable renderable identities—not palettes, camera angles, presets, or thumbnails as separate fractals.

From formula to image

The renderer keeps exploration, history, export, wallpaper, looper, and audio tools on the same view state instead of forking the formula state for each feature.

Precision ladder

Tier	Method	Intended use
1	Realtime GPU	Standard interactive pan, zoom, and parameter changes
2	Extended GPU preview	Deeper double-float or perturbation-backed preview for supported modules
3	CPU Precision	Slower exact-intended refinement for modules with a native CPU formula

The ladder is capability-based. An unsupported module is not labeled “CPU Precision” merely because a synthetic fallback can draw something.

Try it

Browser preview

Open fractal.trebuchetdynamics.com in a modern WebGL 2.0 browser.

1. Pick a card from the catalog.
2. Drag to move; pinch or scroll to zoom.
3. Open controls to change iterations, palette, formula-specific parameters, or a preset.
4. Use the installable app when you need the fullest export, sharing, wallpaper, or precision behavior.

Android

Install Fractal Forge from Google Play for the primary mobile experience.

Run it locally

Prerequisites

• Flutter SDK 3.x (installation guide)
• Dart 3.x, included with Flutter
• A GPU or emulator with shader support; OpenGL ES 3.0+ is recommended

git clone https://github.com/TrebuchetDynamics/flutter-fractal-forge.git
cd flutter-fractal-forge
flutter pub get
flutter run -d chrome

Choose another target with:

flutter devices
flutter run -d linux     # or android, macos, windows, ios

Chrome and Android are the most useful first targets when diagnosing device-specific shader behavior.

Controls

Gesture	2D fractals	3D fractals
Drag	Pan	Rotate
Pinch / scroll	Zoom	Zoom
Double tap	Reset view	Reset view
Long press	Set the Julia seed in the dual viewer	Not used

Common controls include iterations, bailout, power, color scheme, Julia seed, orbit traps, rendering technique, and family-specific coefficients.

Platform support

Platform	Status	Notes
Android	Primary	Maintained Google Play build path
Web	Preview	JavaScript/WebGL 2.0; not full app parity
Linux, macOS, Windows	Development targets	Shader support depends on GPU and driver behavior
iOS	Build target	Requires Apple signing and Metal-backed Flutter rendering

Build release artifacts

flutter build apk --release
flutter build appbundle --release
flutter build web --release
flutter build linux --release

For a Google Play upload build:

1. Copy android/key.properties.example to android/key.properties.
2. Point storeFile to a private upload keystore, preferably outside the repository.
3. Never commit signing files or android/key.properties.
4. Run scripts/build-play-console.sh.

Equivalent Flutter build targets exist for macOS, Windows, and iOS. Linux Fractal Music uses paplay or aplay when available.

Architecture

main.dart
  └─ app shell + Provider services
      └─ HomeScreen
          ├─ CatalogRepository → ModuleRegistry → FractalModule
          └─ FractalViewerScreen
              ├─ GPU / extended preview / CPU precision renderers
              ├─ controls + presets + history + looper
              └─ export + wallpaper + share + Fractal Music

lib/
├── app/              app composition and startup
├── core/             models, controllers, modules, services, theme
├── features/         catalog, viewer, renderer, controls, export, looper
├── l10n/             generated localization output
├── shared/           cross-feature widgets and utilities
└── main.dart         entry point and compatibility facade

shaders/              Flutter GLSL fragment shaders
integration_test/     device and GPU rendering flows
test/                 unit, widget, contract, and golden tests

ModuleRegistry assembles the catalog from declarative configs, shared catalogs, custom builders, and debug-only diagnostics. Every viewer feature consumes the selected module and the same controller state.

Testing

flutter analyze
flutter test
flutter test integration_test/   # requires a device or emulator

Useful focused lanes:

flutter test test/features/renderer/
flutter test test/catalog/
flutter test integration_test/flows/critical_journey_test.dart

See test/README.md for the fast safety lane and test conventions.

Shader development

Shaders live in shaders/ and must be declared under flutter.shaders in pubspec.yaml.

A typical addition is deliberately small:

1. Add or update the .frag shader.
2. Register the asset in pubspec.yaml.
3. Add the module config or builder mapping.
4. Add a focused contract or renderer test.
5. Run a GPU thumbnail/render audit for visual changes.

#include <flutter/runtime_effect.glsl>

precision highp float;
uniform vec2 uResolution;
uniform vec2 uCenter;
uniform float uZoom;
out vec4 fragColor;

void main() {
  vec2 uv = (FlutterFragCoord().xy - 0.5 * uResolution) / uResolution.y;
  fragColor = vec4(uv * 0.5 + 0.5, 0.2, 1.0);
}

Project references

• Renderer backend matrix
• Performance notes
• Shader optimization notes
• Formula coverage limitation
• Launch ladder
• Contributing guide
• Security policy
• Changelog

Contributing

Contributions are welcome. Good first areas include thumbnail quality, presets, shader correctness, web-preview QA, accessibility checks, tests, and documentation. Read CONTRIBUTING.md before opening a pull request.

License

Apache License 2.0. See LICENSE.

Acknowledgments

Built with Flutter. Shader and fractal techniques are informed by the wider mathematical visualization community, including the educational work of Inigo Quilez.