Ray Lab / MAY740

Follow the light. Backwards.

Lighting, Texturing & Rendering · A 2D classroom experiment

Scene cutaway · not the camera’s view

One pixel. One sampled path. Several surface interactions.

SAMPLE 1 / 1

CameraSpecular / glossyDiffuseLight visibility check

100%

Search direction: camera → scene. Light reaching the camera travels the other way. These lines are calculations, not visible laser beams.

How one pixel gets its colour1 complete-path estimate

Selected sample

Average → pixel

Sample history · click to inspect

Every history square is a separate estimate of the SAME pixel, not a different image pixel. Values use complete paths; the scrubber only reveals the diagram.

Experiment controls

Camera pixel 80 / 95

Choose a different viewing ray. Or click the cyan image plane.

Extra surface bounces 3

0 = first visible surface + direct light. Camera rays and light checks do not count.

Floor material

Specular roughness 0.15

Sharp mirrorBroad reflection

Changes the distribution of directions, not the bounce count.

Samples per pixel 1

141664256

Light intensity · relative 4.0

Changes light in the scene. Not photometric units.

Camera exposure · stops 0.0

Changes displayed brightness, not the ray paths.