CrystalEngine is a full-featured, cross-platform game engine with an integrated editor, built from scratch in C++. It features a custom Vulkan/Metal rendering backend with a directed acyclic frame graph for render pass scheduling, a physically-based rendering pipeline with IBL and shadow mapping, and a modular architecture with dynamic module loading. The engine includes a comprehensive asset pipeline (import, compression, serialization), a job system for parallelism, and a physics integration via Jolt. A notable aspect is the dual UI framework: the older CrystalWidgets (CSS-styled) and the newer Fusion framework (declarative, property-based), both used in the editor. The editor provides dockable windows, property editors, material editing, scene outliner, and asset browser. The codebase demonstrates strong engineering with clean abstractions (RHI, RPI, frame graph, job system) but shows signs of ongoing migration (two UI frameworks) and some incomplete features. It is actively maintained and suitable for learning or extending a modern game engine architecture.
Tina is a header-only library providing lightweight user-space threading through coroutines and fibers, along with a fiber-based job system for task scheduling. The core library (tina.h) implements symmetric and asymmetric coroutine APIs with platform-specific assembly for context switching. Tina Jobs (tina_jobs.h) builds on this to create a job scheduler featuring work-stealing via queue chaining, memory pooling, and fiber-based job execution to avoid OS thread overhead. The repository includes examples (e.g., Mandelbrot renderer using Sokol graphics) and tests demonstrating usage, but the project has migrated to Codeberg due to philosophical opposition to AI training, indicating the GitHub repository is no longer actively maintained. While the Sokol dependencies in extras are third-party, the Tina core showcases strong craftsmanship in low-level concurrency primitives.