Demo Engine

Professional Real-Time Graphics Framework for macOS Production

Demo Engine is a professional real-time graphics framework purpose-built for macOS production workflows—broadcast graphics, VJ performance, demoscene productions, and procedural art. It is engineered for high throughput and operational reliability, combining a modern GPU pipeline with production-grade tooling, documentation, and tests.

At its core, Demo Engine provides a dual-renderer architecture with Metal 3 as the primary backend and OpenGL (4.1/4.3) as a compatibility fallback. The engine ships with a large shader preset library and a GPU-accelerated post-processing pipeline, enabling cinematic visuals with deterministic performance characteristics.

Core Capabilities

Dual Rendering Backends (Metal-first)

Demo Engine exposes a unified rendering interface that supports both Metal and OpenGL without fragmenting the application layer. This design allows the engine to:

• Optimize for Apple Silicon + Metal 3 (argument buffers, compute, modern pipeline features)

• Maintain compatibility for older systems via OpenGL fallback

• Preserve consistent resource lifecycles through type-safe handles and RAII-style ownership

Shader Presets + PostFX Composition

A key differentiator is the engine’s production-ready content and compositing model:

• A large preset library (hundreds of shaders) spanning procedural art, transitions, and stylized looks

• A modular PostFX chain featuring 24 GPU effects (bloom, DOF, CRT/VHS, SSAO, motion blur, glitch, grading, etc.)

• Multiple blend modes for layered compositing and transitions

• Effect chaining designed for real-time playback and offline export parity

Audio-Reactive Visual Systems

Demo Engine includes a real-time audio analysis stack designed to drive visuals directly from sound:

• FFT-based frequency analysis with smoothing for stable parameter modulation

• Beat detection and event triggering for rhythmic synchronization

• Parameter bindings that enable “audio as control voltage” behavior for shaders and effects

VJ & Performance Tooling

The platform treats live performance as a first-class use case, incorporating:

• BPM clocking with quantized scheduling (next beat / bar triggers)

• Clip grids and deck-style triggering (Resolume-like operation)

• Layer transitions (wipe, dissolve, cube, zoom, slide, crossfade, etc.)

• MIDI and OSC control surfaces for external hardware and live automation

SVG + Typography System

To support broadcast-style graphics and kinetic identity work, Demo Engine includes a dedicated vector + type subsystem:

• SVG parsing and rendering with transforms, masks, and animation support

• Typography with TTF/OTF, SDF text rendering, variable font axes, and rich text effects

• Integration into the effects pipeline for consistent compositing and post processing

Output Targets & Deployment Modes

Demo Engine supports multiple production outputs, enabling both live routing and offline delivery: • Syphon I/O for macOS live video routing • NDI streaming for network broadcast pipelines • High-resolution export with H.264 / H.265 / ProRes, including 4K+ targets • Headless rendering modes suitable for automation and batch export workflows • Remote control via REST + WebSocket APIs with auto-generated OpenAPI documentation

Reliability, Tooling, and Engineering Rigor

The repository is structured and maintained like a production system, not a demo: • Crash recovery and health monitoring hooks for long-running sessions • Telemetry and diagnostics for profiling and performance validation • Extensive test coverage (unit + integration, including GPU-focused tests) • Build and automation scripts (shell/Python) supporting repeatable builds and performance gating • Deep documentation spanning architecture, shader system, compute, MIDI/OSC, and I/O integrations

Technology Stack

• Core: C++20, Objective-C++

• Rendering: Metal 3, OpenGL 4.1/4.3, GLSL, Metal Shading Language

• macOS APIs: Cocoa, MetalKit, AVFoundation, Accelerate, CoreAudio, CoreVideo, QuartzCore, ImageIO

• Testing: GoogleTest, shell/Python build/test workflows