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CRT·XDR
A CRT simulation for Mac Retina HDR displays. Native macOS, Metal, single file.
Modern CRT filters must darken the image to draw scanlines and phosphor masks.
This one doesn't: it renders into an rgba16Float extended-linear-sRGB
CAMetalLayer with EDR enabled, so a flat white area still averages to
standard SDR white while the scanline beam crests and lit phosphors ride
2–3× brighter into the display's EDR headroom — the same way a real tube's
electron gun overcomes its shadow mask. At ~254 ppi the simulated 0.3–0.6mm
phosphor triads are drawn per physical pixel at true dot-pitch scale, and
120Hz ProMotion allows a real rolling 60Hz beam with phosphor decay.
Modeled physics
- Gaussian beam spot with brightness-dependent blooming, energy-normalized
- Aperture grille and slot masks at 0.3/0.6mm pitch; slot phosphors are discrete rounded pills (staggered brick) that integrate the beam per cell, with soft deposition edges and static powder grain
- SMPTE-C phosphor chromaticities (with optional 9300K consumer white), tube EOTF gamma 2.4 vs the 2.2 signal
- Per-phosphor P22 decay (red Y₂O₂S:Eu ~1ms lags the green/blue sulfides)
- R/B misconvergence growing from zero at center toward the edges
- Halation from faceplate glass scattering, corner vignette
- Spherical tube curvature; cylindrical (flat-vertical) for grille modes
- Optional rolling 60Hz scan and 480i interlace line twitter
- Built-in EDR test strip (1×/2×/4×/max SDR white) to verify HDR is live
Build & run
swiftc -O main.swift -o crt-xdr
./crt-xdr
Requires a Mac with an EDR-capable display (any recent MacBook Pro XDR panel; falls back to SDR elsewhere). Signals: SMPTE bars, green-phosphor terminal, plasma demo, or drag any image onto the window.
Keys: 1–4 scene · M mask · R rolling scan · I interlace ·
T EDR test strip · F fullscreen · H hide controls
Similar repos
Languages
Swift
100.0%
See what people are saying (1)
README
CRT·XDR
A CRT simulation for Mac Retina HDR displays. Native macOS, Metal, single file.
Modern CRT filters must darken the image to draw scanlines and phosphor masks.
This one doesn't: it renders into an rgba16Float extended-linear-sRGB
CAMetalLayer with EDR enabled, so a flat white area still averages to
standard SDR white while the scanline beam crests and lit phosphors ride
2–3× brighter into the display's EDR headroom — the same way a real tube's
electron gun overcomes its shadow mask. At ~254 ppi the simulated 0.3–0.6mm
phosphor triads are drawn per physical pixel at true dot-pitch scale, and
120Hz ProMotion allows a real rolling 60Hz beam with phosphor decay.
Modeled physics
- Gaussian beam spot with brightness-dependent blooming, energy-normalized
- Aperture grille and slot masks at 0.3/0.6mm pitch; slot phosphors are discrete rounded pills (staggered brick) that integrate the beam per cell, with soft deposition edges and static powder grain
- SMPTE-C phosphor chromaticities (with optional 9300K consumer white), tube EOTF gamma 2.4 vs the 2.2 signal
- Per-phosphor P22 decay (red Y₂O₂S:Eu ~1ms lags the green/blue sulfides)
- R/B misconvergence growing from zero at center toward the edges
- Halation from faceplate glass scattering, corner vignette
- Spherical tube curvature; cylindrical (flat-vertical) for grille modes
- Optional rolling 60Hz scan and 480i interlace line twitter
- Built-in EDR test strip (1×/2×/4×/max SDR white) to verify HDR is live
Build & run
swiftc -O main.swift -o crt-xdr
./crt-xdr
Requires a Mac with an EDR-capable display (any recent MacBook Pro XDR panel; falls back to SDR elsewhere). Signals: SMPTE bars, green-phosphor terminal, plasma demo, or drag any image onto the window.
Keys: 1–4 scene · M mask · R rolling scan · I interlace ·
T EDR test strip · F fullscreen · H hide controls
Similar repos
Languages
Swift
100.0%