Phosphor

A physically-based X-Y CRT simulator in Rust. Rather than approximating the visual appearance of a CRT, Phosphor models the actual physics of phosphor emission, decay, and electron beam behavior.

Status: Early development.

Features

• Spectral phosphor model — 16-band spectral representation (380–780nm) with CIE 1931 colorimetry
• Three-tier hybrid decay — Instantaneous exponentials (tier 1), slow multiplicative exponentials (tier 2), and power-law decay from bimolecular recombination (tier 3), based on Kuhn (2002) PMT measurements
• Dual-layer phosphors — Supports phosphors with distinct fluorescence and phosphorescence (P2, P7, P14, etc.) with independent emission spectra and decay terms
• GPU accumulation buffer — Scalar-layer storage buffer with beam write, spectral resolve, decay, faceplate scatter, and composite passes running entirely on the GPU via wgpu compute/fragment shaders
• Multiple input modes:
  • Built-in oscilloscope signal generators (sine, triangle, square, sawtooth, noise)
  • Stereo audio files as X/Y input (oscilloscope music)
  • Vector display lists (JSON)
  • External protocol over stdin/Unix socket
• CRT display effects — Faceplate scatter/halation, glass tint, screen curvature, edge falloff, tonemapping (Reinhard, ACES, Clamp, HDR passthrough)
• HDR output — Automatic Rgba16Float surface when the display supports it
• GPU profiling — Per-pass timestamp queries with timing history plots

Building

Requires Rust 2024 edition (1.85+) and GPU drivers with wgpu support.

cargo run --release

Nix

A flake is provided for Linux:

nix run

Input Modes

Oscilloscope

Built-in waveform generators drive the X and Y axes. Useful for Lissajous figures and testing.

Audio

Load a stereo audio file (WAV, FLAC, OGG, MP3) where the left channel drives X and the right channel drives Y — the format used by oscilloscope music.

Vector

A display list of line segments with per-segment intensity control, loaded from JSON files.

External

A text protocol over stdin or Unix socket for driving the beam from external programs:

B x y intensity dt      # beam point
L x0 y0 x1 y1 intensity # line segment
F                        # end frame

Phosphor Types

Phosphor definitions are based on the 1966 Tektronix CRT Data sheets (included in docs/crt-info/). Supported types include P1, P2, P3, P4, P7, P11, P14, P15, P17, P20, P24, P31, P32, and others. Each phosphor has physically measured decay parameters — bi-exponential (Selomulya 2003) for silicate phosphors, power-law + fast exponentials (Kuhn 2002) for ZnS-based phosphors.

Keyboard Shortcuts

Key	Action
Ctrl+D	Toggle detached controls window
Ctrl+F	Toggle fullscreen
Ctrl+Q	Quit

License

This project is licensed under the Mozilla Public License 2.0.