ghostty-blackhole

Ghostty Blackhole

Landing page: s13k.dev/blackhole

A black hole floating inside your Ghostty terminal. It
starts small and grows to swallow your screen, driven by whichever size mode
you pick: a built-in *pomodoro* clock (grow through the hour, demand a break,
leave you alone once you take it), or *token mode*, where it tracks how full
Claude Code's context window is in real time.

Modeled on Eric Bruneton's black hole shader,
which beam-traces Schwarzschild geodesics against precomputed lookup tables.
A Ghostty custom shader is a single Shadertoy-style fragment pass with no
custom textures, so the lookup tables are replaced by doing the physics live:
every pixel near the hole integrates its own null geodesic through the
Schwarzschild metric (the Binet-form acceleration a = -3/2 h² x/r⁵, which
gives the exact photon bending). Your terminal contents play the role of the
lensed background sky. Nothing below is painted on — it all falls out of the
ray tracing:

What it renders

- The shadow — rays with impact parameter under b_crit = (3√3/2) r_s
  spiral through the horizon and come back black. Text near the edge is
  stretched into the photon ring before it disappears; text behind the hole
  really is gone.
- Gravitational lensing — escaped rays are projected back onto the
  terminal "sky" plane: text bends, magnifies, and shows the mirrored
  secondary image inside the Einstein ring. Far from the hole this hands off
  to the analytic weak-field deflection (α = 2r_s/b), so only pixels near
  the hole pay for the integration. Blue bends slightly more than red out
  there for a touch of chromatic aberration.
- Accretion disk — a thin Keplerian disk that a ray can pierce several
  times: the far side arcs *over and under* the shadow (the Interstellar
  look), and the…