Ray-tracing Room
Move the light. Inspect the paths behind reflections, shadows, and color.
Drag the light handle. Watch the shadows and reflections move. Grain decreases as samples accumulate.
Rendering model
A pinhole camera samples paths through a 3D room. Matte surfaces use cosine-weighted diffuse scattering and explicit area-light sampling. The mirror is ideal; glass uses Snell refraction, total internal reflection, and a Schlick Fresnel approximation at index 1.5.
Paths stop at the selected interaction limit. Shadows treat glass as an occluder for direct-light samples, so focused glass caustics are poorly sampled here. No spectral dispersion, participating media, or denoising. Brightness uses a fixed display tone map.
The light’s emitted radiance stays fixed as its size changes: a larger source is softer and also emits more total power. Rendering is bounded to 32 samples, or 128 on request, in a cancellable worker.
Path tracing and light sampling