//! The application: renderer, hardware models, and the frame loop.
//!
//! Reimplements the pieces of the PlayStation 2 that the game talks to, so the
//! game logic in `gc-game` can be written as ordinary Rust that draws and
//! sounds like the original.
//!
//! # Hardware being modelled
//!
//! * **Graphics Synthesizer (GS)** - fixed-function rasteriser. No shaders on
//!   the real hardware: the GS does texture mapping, alpha and blend rules,
//!   and z/stencil. Here that becomes wgpu plus explicit handling of the GS's
//!   own rules (its `round(log2(z/n) + K)` mip selection, its blend and alpha
//!   test behaviour, its alpha-0x80-is-1.0 convention).
//! * **VU0 / VU1** - vector units running microcode uploaded from the disc.
//!   Skinning, lighting and transform setup live here. The microcode is
//!   **binary** in the game's `.vutext` section, so it is reverse engineered
//!   rather than parsed: this is the single hardest item in the project.
//! * **DMA and GIF/VIF packets** - the game streams geometry to the GS through
//!   tag-split packet lists. Those packet formats are the input to rendering.
//! * **SPU2 / IOP** - audio and the disc interface, in `gc-video` and
//!   `gc-extract` respectively.
//!
//! # Divergence from the first game
//!
//! R&C2's levels are spherical worlds, so camera, culling, fog and the sky are
//! all effectively rewritten compared with Ratchet & Clank (2002). Geometry
//! subsystems carry over in shape - `tfrag`, `tie`, `shrub`, `moby` are the
//! same four - but their behaviour on a sphere is new work.
//!
//! # Reference frame
//!
//! The port is validated against PCSX2 by replaying recorded input and
//! comparing frames. Without that loop, "looks close" and "is correct" drift
//! apart, and this game's difficulty and movement make that drift very
//! noticeable.

pub mod level;
pub mod ps2;
pub mod tfrag_light;