Scotopic Vision: 3D Retinal Cell Map

This simulation builds an orbitable 3D model of the retina's photoreceptor mosaic instead of just desaturating a scene. A concave spherical-cap surface represents the back of the eye, carrying two instanced particle populations positioned by their real anatomical density: cones cluster tightly in the central foveal pit and thin out toward the periphery, while rods are completely absent from that same fovea and grow denser outward, exactly as measured in the human retina. Drag the ambient-light slider down and watch cone activity fade while rod activity takes over everywhere except the dark, rod-free center — the anatomical reason night vision has a literal blind spot at your point of fixation. The bright-flash button bleaches rhodopsin, the rod pigment, and a real recovery timer shows rod sensitivity climbing back as the eye dark-adapts.