Files
spice2x.github.io/src/spice2x/hooks/graphics/backends
bicarus d51de976b1 graphics: move captures off-thread when streaming (#885)
## Link to GitHub Issue or related Pull Request, if one exists
#0

## Description of change

Moves the API capture readback off the game's Present thread while a
video stream client is connected.

The readback is a `LockRect` plus a memcpy of the whole back buffer,
roughly 635us at 720p and 1270us at 1080p. On the Present thread that
comes out of the game's frame budget: TDJ (at 120Hz) dropped to 117fps
with a 60fps stream running, and reading on a pool thread instead gave
the full 120 back.

Only streaming takes the off-thread path, gated on a new
`capture_pump::screen_claimed()`.

Screenshots, one-off API captures, and `THREAD_BAN` games all keep the
existing inline read for compat reasons. A pool thread in `LockRect`
while the Present thread sat inside `GetRenderTargetData` deadlocks DDR
X2 for example.

`CLAIMED[]` becomes `std::atomic<bool>` so the capture path does not
take a lock on the Present thread. The read pool has a single worker so
frames cannot be enqueued out of order, and both capture pools are never
destroyed so a late read cannot queue onto a torn-down pool.

The capture pipeline itself is unchanged: `GetRenderTargetData` is still
synchronous on the Present thread.

## Testing
DDR X2
World
IIDX TDJ
SDVX VM
2026-08-22 11:11:07 -07:00
..
2026-08-16 21:23:41 -07:00