Metal Shader Explorer

Metal Shader Explorer

Native macOS Real-Time Procedural Shader Playground (Metal + C++20)

Metal Shader Explorer is a native macOS application for exploring procedural 2D fragment shaders in real time. Built for performance and immediacy, it uses Apple Metal with a CVDisplayLink-driven render loop to deliver smooth, vsync-synchronized animation while keeping the CPU lightweight and the GPU fully utilized.

The app ships as a self-contained, dependency-free macOS build—leveraging only Apple frameworks—making it fast to build, easy to run, and highly portable across Metal-capable Macs.

The result is a “visual instrument”: a fast feedback loop for iterating on shader ideas, discovering new looks, and building repeatable visual palettes.

Architecture & Rendering Pipeline

The rendering model is intentionally simple and GPU-forward: 1. CVDisplayLink triggers the frame callback at the display refresh rate 2. A lightweight time system updates time / deltaTime (respecting pause and speed) 3. The app updates a uniform buffer each frame with the active shader’s parameters, seed, resolution, and input state 4. A fragment shader executes per-pixel on the GPU 5. The UI overlay is rendered to a texture and composited over the shader output 6. The final frame is presented through a Metal-backed view/layer

This approach achieves high frame rates by keeping the hot path tight: uniform updates + a single GPU pass, with clean separation between visual generation and UI.

Native UX & Interaction Design

The interface is optimized for quick iteration: • Overlay sliders for continuous parameter control • Keyboard shortcuts for show/hide UI, shader browsing, pause, fullscreen, seed randomize/mutate, preset load/save • Fast “scan through looks” workflow using next/previous shader navigation • Preset slots that support rapid A/B testing and live exploration

Quality, Testing & Reliability

A standout aspect of the project is its engineering rigor for a creative tool. The repository includes a substantial automated test suite covering: • UI layout and hit testing • Core timing and input systems • Preset storage and serialization • State management and utilities • Metal/GPU functionality (shader compilation, pipeline creation, dispatch)

Coverage is reported at ~98% line coverage, with gating scripts and Make targets to enforce thresholds and prevent regressions.

Build & Tooling

Build and run are intentionally streamlined: • Makefile-first workflow, Metal as the default target • Optional legacy OpenGL path for older compatibility needs • Separate test targets, coverage generation, and gated build scripts

This keeps iteration fast for shader development while still supporting disciplined CI-style validation.