Shader physics (per-pixel GLSL)
① Grav. lensing — Schwarzschild null-geodesic deflection. Shadow at b꜀ = 3√3/2 · Rₛ.
② Blackbody — Planck B(λ,T) → CIE XYZ → sRGB. T ∝ ρ/r³⁄₄ (thin-disk).
③ Doppler beaming — Keplerian β(r) projected by inclination. I_obs = I_emit · δ³.
④ Grav. redshift — z = (1 − Rₛ/r)^½ shifts T and dims emission.
⑤ Tone mapping — ACES filmic + γ=2.2 sRGB.