Run clang-format (the repo's .clang-format: LLVM base, 120 cols, tabs,
Allman functions) over every source file so the tree is formatter-clean.
Whitespace only -- no behavior change; full x64 + x86 suites pass.
Also set SortIncludes: false in .clang-format. Windows include order is
load-bearing (windows.h must precede tlhelp32.h / mmreg.h / xinput.h /
dinput.h; winsock2.h must precede windows.h), and the default
alphabetical sort reorders tlhelp32.h ahead of windows.h -- a build
break. Leaving order alone keeps the manual, correct grouping.
The vk_capture_perf_test comments described its synchronous reference
arm as "the OLD code"; it is a deliberately-constructed slow baseline
the test compares against, not removed history -- reworded to say so.
Replace the last std::getenv (tone_source.hpp) with
GetEnvironmentVariableA, dropping the C4996 deprecation warning from
every audio-tone build, and drop the now-unused cstdint/cstdlib
includes. Generalize a game-name aside in the header comment.
Against Sphere Spectacle (144 FPS, runs without Steam) the implicit-layer
capture dropped the game to ~3 FPS. Measured cause (per-stage trace in the
layer): the read-back ran on the game's PRESENT THREAD and spent ~370 ms per
1080p frame -- not the GPU copy (~2 ms) but the CPU swizzle, because the staging
buffer was a plain HOST_VISIBLE|HOST_COHERENT type (write-combined / uncached on
a discrete GPU), where a scattered CPU read runs at PCIe latency. 3 captures/s =
the 3 FPS the user saw.
Test-first: tests/vk_capture_perf_test reproduces the stall as a deterministic
unit test (372 ms/present, ratio 1.0 -> FAIL via `--sync`), then proves the fix
(0.02 ms/present, byte-correct BGRA->RGBA, ratio ~0 -> PASS).
Fix: extract the near-identical read-back from vk_hook.cpp and coop_vk_layer.cpp
into one shared coop::hook::VkCapture that:
* has the present thread only record + submit the copy (sub-ms) and return;
* runs a dedicated reaper thread for the fence wait + swizzle + D3D upload, off
the critical path, with a ring of in-flight slots (game never waits);
* allocates HOST_CACHED staging (fast CPU read), invalidating when non-coherent;
* throttles capture to ~150 Hz (a guest stream is <= the host refresh; no point
mirroring an uncapped 400+ FPS game and burning reaper CPU).
Real-game A/B: present rate now matches the no-capture baseline (605->470 vs
593->405 over the same ramp) with the mirror at ~130 fps -- no measurable impact.
Also adds present-thread overhead guards to the other GPU backends' hook tests
(present_overhead.hpp): DX11 0.05 ms, DX12 0.34 ms, OpenGL 0.09 ms overhead, all
asserted < one 60 Hz frame, so any future synchronous-stall regression fails.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
