Educational lensing demo focused on how spacetime curvature bends geodesic-like light paths near a compact mass.
Viewer focus: how trajectories bend as mass increases.
Coordinate frame: 2D screen-space projection (x, y) shown as the grid on the canvas.
Units: radius is pixels from mass center, mass is a dimensionless curvature proxy, time-step is simulation dt per frame, distortion scale sets bend strength.
This uses a Schwarzschild-inspired weak-field approximation: each ray receives a small inward deflection proportional to (mass · distortion) / r².
Physically grounded: stronger mass gives stronger bending; farther rays bend less; small-angle deflection trend matches weak-field intuition.
Pedagogical simplifications: flat 2D rendering, no full tensor metric solve, no true null geodesics in 4D spacetime, and no redshift/time dilation integration.
Known limitations: unstable in extreme mass regimes, not valid near a true event horizon, and intended for intuition rather than quantitative prediction.