PSF/Blurring. Turned out to be tough

readme.md

@@ -160,7 +160,8 @@ cargo run --release -p resolved-showcase -- --serve 0.0.0.0:8010
   either way.
 - `--timings N` renders N frames and reports setup and per-frame times.
 - `--lighting L0|L1` and `--camera C0|C1` pick the fidelity tiers (default
-  L0 and C0). A tier the scene or the data cannot support stops with an error
+  L0 and C0). `--supersampling N` renders each pixel as N x N finer ones from C1
+  (default 2). A tier the scene or the data cannot support stops with an error
   naming what is missing.
 - `--data DIR` says where the tiers' data is (`earth/bmng-2004-MM.jpg` and
   `moon/wac-hapke-643.png`).
@@ -188,9 +189,10 @@ and targets to DN through `Renderer`, and the CLI renders scene files. Lighting
 L1 draws Earth's surface from Blue Marble and the Moon's from the LRO Camera's
 map, shadows on the target, light from Earth and the Moon on it, eclipses on
 Earth and the Moon, and the Sun's limb darkening. Camera C1 is under way: so
-far, pixels that collect light over their area. Planned, in order:
+far, pixels that collect light over their area, and lens blur (a Gaussian
+PSF) applied to the scene rendered 2 x 2 finer than the pixels. Planned, in order:
 
-- Camera: lens blur (PSF), lens distortion, apparent positions, stars,
+- Camera: lens distortion, apparent positions, stars,
   detector noise, pixel-to-pixel variation, saturation and blooming.
 - Lighting: BRDF and spectral materials, atmospheric scattering, clouds, lunar
   terrain.