Add an optional CPU preview path that deposits each point-source image as a
supersampled delta and resolves the whole frame with one global Moffat
convolution plus an N x N box average, instead of splatting a per-event PSF.
- optics: FastPsfAccumulator builds the pixel-area-integral kernel of the
target Moffat at the supersampled scale (width N*alpha, same beta). The
1/N^2 box average then reproduces the final pixel-area integral, so the
requested FWHM and beta are preserved without renormalisation. Deposits are
per-cell atomic adds; resolve accumulates into the caller's HDR buffer.
- frame: fast branch in frame_splat_catalog with one shared supersampled
buffer and a single resolve per frame; the accumulator is reused across
movie frames and built from the map dimensions on lens-map import.
- main: --fast-mode, --fast-supersample N (1..8, default 2) and
--fast-deposit nearest|bilinear (default nearest). CPU-only and rejected in
the HIP/dummy backends; --psf-min-y still applies per event while
--max-cache-psf-flux does not.
- The deposition scheme was chosen by scripts/fast_mode_deposit_error.py:
nearest keeps the PSF shape exactly with <= 0.5/N px position quantization;
bilinear keeps the exact centroid but broadens FWHM and beta. Recorded in
benchmarks/fast_mode_deposit_2026-09-18.md.
- tests/test_frame.c covers fast nearest vs the direct evaluator at the snapped
centre, flux conservation, bilinear centroid, min-Y discard, frame plumbing,
and HDR accumulation onto a non-zero background.
- benchmarks/fast_mode_cpu_2026-09-18.md records a ~10x speedup on the 2MASS
galactic-centre field with small tone-mapped differences.
Replace the artifact-affected Schwarzschild image with the corrected 4K render. Link both READMEs to the paired CPU/HIP benchmark and clarify that this run had no PSF wing clipping or direct fallbacks.
Cooperate across 32 lanes per PSF and use two completion-protected staging slots with complete batch timing. Restore coarse OpenMP event production while serializing shared GPU submissions and direct fallback boundaries.
Add bounded benchmarks, streaming and renderer regressions, and preserve validation evidence and ownership documentation.
Integrate timelike geodesics and Fermi-Walker tetrads in ingoing Kerr-Schild coordinates, sampled at a configurable proper-time cadence.
Add movie-track-samples to preserve CSV events as frames. Document usage and singularity guards, and cover analytic orbits, transport convergence, sampling, and CSV rendering.
wyj