With Shader Cache Size disabled in NVIDIA Control Panel, the driver walks
the whole system drive inside D3D12CreateDevice (traced by the reporter
to NvMemMapStoragex.dll!TotalDiskUsage), before the window's first
frame; Driver Default fixes it (confirmed in #374, PhotoCraft too). The
launch-argument walk found on the way was fixed in #394.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01912WaK6Rmew3wxZuPyX7E8
`--help`, the module doc and the README promise that a `--memory` session
"writes nothing", and the desktop app broke that in two places:
- `PrefsWriter` saved `ui.json` whenever the UI state changed (issue #164),
so a throwaway session's `thumbSize`, window layout or language replaced
the user's saved settings — the README showcase script does exactly that.
- The GPU crash sentinel from #136 armed itself in every session except
`LIGHTCRAFT_NO_PREFS` (issue #169); `with_init_marker` creates the
settings folder to hold `gpu-init.marker`, removes the marker and leaves
the folder, so a `--memory` run on a fresh home left an empty
`Library/Application Support/LightCraft` behind.
Now `PrefsWriter` carries its target path (`None` for `--memory`,
`LIGHTCRAFT_NO_PREFS` or no home folder) and writes nothing without one; it
also writes nothing while the session is the one offered when the library
can't be opened (the question window and Continue Without Saving, which
`docs/control-protocol.md` already describes as writing nothing) and
resumes when `app.openLibrary` ends it. `gpu_crash_check(in_memory)` neither
arms the sentinel nor removes a marker in a `--memory` session; it still
reads one (new `read_init_marker`), so GPU rendering starts off there too
and the next ordinary launch reports and clears it. A `--memory` session
still reads `ui.json`, but a damaged one is reported and left in place
rather than set aside. Normal launches are unchanged.
Tests: `prefs_writer_writes_nothing_in_a_memory_or_temporary_session`,
`memory_session_leaves_the_gpu_marker_and_folder_alone`,
`memory_session_leaves_a_damaged_ui_json_alone` (apps/lightcraft), and
`read_init_marker` coverage in the gpu crate's marker test.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The coverage mask from 94fe300 evaluated the f64 warp for every output
pixel. coverage_mask now asks Warp::block_coverage for each 32 x 16 block
(the shared warp formulas evaluated with outward-rounded intervals, no
edge margin) and evaluates only undecided blocks near the edge per pixel
with Warp::covers; the bits are unchanged
(coverage_mask_matches_per_pixel_decision, incl. partial words and
padding bits; coverage_mask_with_the_horizon_in_view, a perspective
denominator exactly 0 inside the image, so the clamp and
undecided-division paths go through block_coverage and the mask).
Measured (release, synthetic source, embedded lens warp + CA +
perspective as in embedded_lens_perspective_edges_match):
6000x4000 ~30 ms -> 2.7 ms (32 threads, 11x), ~580 ms -> 24.5 ms
(1 thread, 24x); 2048x1365 3.6 ms -> 1.0 ms (3.5x), 67.5 ms -> ~5 ms
(12-14x). Rotate270 the same.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The lens + perspective warp classified source-edge pixels in f32 on the GPU.
A position 0.000035 px outside the edge rounded inside, so the GPU sampled
photo pixels where the CPU reference draws blank canvas (geometry_variants,
"embedded lens + perspective", max 91 LSB). The CPU now evaluates the f64
framing decision into a one-bit-per-pixel mask; sampling and colour stay on
the GPU. The embedded-lens cases move to their own test,
embedded_lens_perspective_edges_match, with the same tolerances.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
wgpu loads the driver of every backend in an instance's set while it
enumerates adapters. The compute device (crates/gpu) hard-coded
Backends::PRIMARY (Vulkan + DX12 + Metal) and ignored WGPU_BACKEND, and
was created from LightcraftApp::new on a background thread at launch, so
a crashing Vulkan driver (Intel UHD 630, igvk64.dll) killed the process
before the window appeared; the window (egui-wgpu) also listed Vulkan.
- lightcraft_gpu::backend: DX12 only on Windows (Metal on macOS, as before
on Linux) for both the compute device and the window;
LIGHTCRAFT_GPU_BACKEND=dx12|vulkan|metal|gl|auto|off, else WGPU_BACKEND;
backends missing from the build fall back to the default.
- The device is created only when GPU rendering is enabled, after the
first frame; the preference is applied before the window opens.
- Crash sentinel: gpu-init.marker in the settings folder around device
creation; if left behind, the next launch starts with GPU rendering off
and a notice saying how to turn it back on.
- Tests: backend parsing/selection, sentinel, window defaults, headless
snapshot with LIGHTCRAFT_GPU=0 / LIGHTCRAFT_GPU_BACKEND=off.
- Docs: gpu-pipeline.md (backends, env vars, troubleshooting), whats-new,
parity LR-BEHAV-GPU.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A GPU render no longer hands back an image it cannot vouch for:
- set the wgpu device-lost callback (wgpu never reports a lost device as an
error, so a driver reset went unnoticed); readback waits with a timeout and
checks the poll result and map callback instead of blocking forever
- each render runs in OutOfMemory/Validation/Internal error scopes; errors
fail that render (OOM and limit failures for that render only, device
errors for the process) and it is redone on the CPU
- every buffer is checked against the device limit when created (no
validation error, no process-wide disable); LIGHTCRAFT_GPU_LIMITS=webgpu|<MiB>
creates the device with lower limits to reproduce small adapters
- the output buffer is cleared and the per-pixel kernel writes alpha 255:
any unwritten pixel (work silently dropped, the issue's all-black export)
fails the render; an all-black result is re-rendered on the CPU
- renders submit per stage and every 16 M invocations, the per-pixel stage
runs in ~4 MP bands: no long submission for a slow iGPU's watchdog to reset
- ui.inspect perf.gpuReason / perf.gpuFallback, app.gpu reason/lastFallback,
System Info and Settings say why the GPU is off (e.g. llvmpipe skipped) and
why the last render fell back
Tests: crates/gpu/tests/fallback.rs (limit, mid-render limit, validation
error, dropped work, black photo), engine export falls back to the CPU image,
banded 3000x2000 GPU/CPU equivalence.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- memory::budget (default min(25% RAM, 1.5 GiB); LIGHTCRAFT_MEMORY_MB, app.memoryBudget):
half for engine caches (sources + rendered previews, LRU across them via a global
use tick; the photo on screen stays), a quarter for decodes in flight (WorkGate:
thumbnails, prefetch and import probes wait; loupe/export loads never wait), an
eighth for the GPU free pool.
- GPU: best-fit buffer reuse (<= 25% slack), buffers released outside a render are
pooled at once (no stranded retired lists), pool trimmed after 3 s idle.
- Decodes drop file bytes and raw samples early, colour/crop/orient in place.
- macOS: apps install malloc_zone_pressure_relief as the release hook (after each
decode, import and idle trim): freed large blocks no longer stay resident.
14 raws + loupe + 12 steps (M4 Pro): peak RSS 1.9-2.3 GB -> 0.83-0.99 GB, footprint
2.5-2.6 GB -> 0.91-0.96 GB, heap peak 930 -> 656 MB; stepping median ~13 ms.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- Once the current photo's loupe render is done, the next and previous photos in filmstrip
order get a background loupe job (Slot::Prefetch, priority below on-screen thumbnails,
once per settings): the decoded 2560 px source is kept in the engine's bounded preview
LRU and the view render is cached, so stepping to a neighbour shows its developed image
in ~50 ms and then re-renders only on the GPU.
- lightcraft_gpu::warm_up (called when the app is created) builds the device and kernels on
a background thread; gpu::ready() answers without blocking and ui.inspect uses it, so the
UI thread never waits for device creation.
- docs/gpu-pipeline.md: opening-a-photo section.
Stepping through 24 MP raws in the loupe (real app): full render 220–580 ms → 45–62 ms.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
`media::develop` renders on the GPU when available (views, render_now, exports;
thumbnails stay on the CPU) and falls back to the CPU otherwise. `app.gpu
{enabled?}` toggles it at runtime, `LIGHTCRAFT_GPU=0` disables it for the process,
`ui.inspect` reports the adapter under perf.gpu.
Performance: dropped device buffers are recycled once their thread has submitted
(fresh 100-300 MB allocations per pass cost as much as the passes), Gaussian
passes ping-pong between two buffers and read all channels of a pixel at once,
and long box radii slide over longer chunks. LIGHTCRAFT_PROFILE prints real GPU
stage timings. render_bench prints CPU and GPU columns and the CPU/GPU difference.
24 MP ARW, loaded machine, min of 7: cold loupe 415 -> 32 ms, exposure drag
22-42 -> 3.9 ms, NR drag (1920) 301+ -> 18 ms, export render 1037+ -> 291 ms;
max 1 LSB difference. docs/gpu-pipeline.md describes the implementation.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude
wstock
radialmonster
Brandon Thomas