The black hole

Render a black hole with an accretion disk, Interstellar-style — gravitational lensing done per pixel.

Build

• Full-window canvas. For every pixel, march or analytically bend a light ray past a Schwarzschild black hole (an approximate deflection formula is fine — the behavior must be right).
• A thin, hot accretion disk in the equatorial plane: rays that cross the disk plane inside its radius pick up its color, orange-white hot at the inner edge cooling outward.
• Because of lensing, the far side of the disk must appear as arcs above and below the shadow — the signature image.
• A crisp photon ring just outside the event horizon, and a lensed background starfield that smears into arcs near the shadow's edge.
• Doppler beaming: the side of the disk rotating toward the camera is visibly brighter.
• Drag to tilt the camera from edge-on to face-on; a slider for exposure.
• Render at reduced internal resolution and upscale to hold 30 fps or better.

What separates great from passable

• Tilting the camera continuously reshapes the lensed arcs — face-on shows a ring, edge-on shows the full "hat" image.
• The shadow stays perfectly black; no stars or disk leak inside the photon ring.
• No frame hitches while dragging — buffers reused, nothing allocated per frame.