$ show 3b1b/manim
ManimGL is a mature, well-architected Python library for programmatic mathematical animation, using OpenGL (via ModernGL) for GPU-accelerated rendering. Originally created by Grant Sanderson (3Blue1Brown), it is the upstream predecessor to the community edition. The codebase is structured as a library with a CLI entry point (`manimgl`), and it cleanly separates concerns into animation logic, scene management, camera/frame transforms, mobject (math object) types, shader pipelines, and utility modules. The architecture centers on a scene-graph model: `Scene` objects orchestrate `Animation` instances that interpolate between `Mobject` states, while a `Camera` with a `CameraFrame` handles view/projection and feeds into a shader-based rendering pipeline. The system supports real-time interactive preview via an embedded IPython shell, video export via FFmpeg piping, and LaTeX-to-SVG conversion for text. The GLSL shader system is notably sophisticated, with custom `#INSERT` preprocessing to share code between vertex/fragment/geometry shaders for quadratic Bézier rendering, fractals, and lit surfaces. Key reusable components include: a robust event-driven interactive system (event dispatcher + listeners), a disk-caching decorator for expensive computations, a deeply capable Bézier/geometry math library, a flexible color system with colormaps, and a module-reload system that enables live coding. The codebase demonstrates high craftsmanship in its shader architecture, the `CameraFrame` as a fully animatable mobject, and the `TransformMatchingParts` algorithm for morphing between shapes.
The LLM identified 8 files worth highlighting for reuse:
A singleton EventDispatcher that manages typed listeners (mouse, keyboard) and dispatches events with propagation control. It tracks mouse position, drag state, and pressed keys, and supports draggable-object hit testing. The clean separation of event types, listener registration with operator overloading (__iadd__/__isub__), and the dispatch logic for mouse vs. keyboard events make this a reusable pattern for any interactive OpenGL/pyglet application.
A disk-backed caching decorator (`cache_on_disk`) using the `diskcache` library with a 1GB limit. It hashes function arguments to create cache keys, avoiding redundant expensive computations (e.g., LaTeX compilation). The pattern is generic and extractable for any project needing persistent, size-bounded memoization.
A comprehensive Bézier curve library including evaluation, partial curves, smooth handle computation via tridiagonal solvers, arc-length parameterization, and cubic-to-quadratic approximation (with fontTools fallback). The `smooth_quadratic_path` and `approx_smooth_quadratic_bezier_handles` functions solve the non-trivial problem of fitting smooth quadratic splines through points, making this a valuable standalone geometry toolkit.
A color system bridging the `colour` library, hex/RGB conversions, HSL interpolation, and matplotlib colormaps. The `get_colormap_from_colors` function returns a vectorized mapper from scalar values to RGBA arrays, useful for heatmaps and magnitude visualization. The `interpolate_color` with sqrt-correct RGB blending is a non-obvious, physically-motivated detail.
A module loader that supports live reloading of user code during interactive sessions. It tracks imports by monkey-patching `builtins.__import__`, then recursively reloads only user-defined modules (excluding stdlib/site-packages) while preserving global config. This enables the `reload_scene()` workflow and is a sophisticated pattern for any tool requiring live code updates.
Implements `TransformMatchingParts` and `TransformMatchingStrings`, which automatically match sub-mobjects between a source and target by shape or by longest-common-substring (via `difflib.SequenceMatcher`), then fade unmatched parts in/out. This solves the common animation problem of smoothly transitioning between two diagrams, and the string-matching variant is particularly clever for morphing LaTeX/Tex expressions.
Manages ModernGL shader programs with a uniform-mirroring system (`PROGRAM_UNIFORM_MIRRORS`) to avoid redundant GPU uploads, and a custom `#INSERT` preprocessor that emulates `#include` for GLSL by injecting shared code snippets (e.g., lighting, complex math). This abstraction significantly reduces boilerplate in shader-heavy applications and the uniform caching is a meaningful optimization.
A `CameraFrame` that is itself a `Mobject`, allowing the camera to be animated and manipulated like any other object. It uses `scipy.spatial.transform.Rotation` for orientation, supports Euler angles with gimbal-lock handling, and computes view matrices for the shader pipeline. The design of making the camera a first-class animatable entity is elegant and enables complex 3D scene choreography.