feed

The newest frame a capture produced on this engine, and who is watching for it.

Every capture core publishes here. latest() is that frame: a src an image widget draws (the render target's guid while the engine still holds it, the written path when the capture produced a file), with the size, the source and the pass beside it. watch(fn) calls fn as each new frame arrives, and unwatch(token) drops the subscription.

shown() says a viewer is drawing frames from the feed. From then on the feed holds the newest capture's render target so the picture stays up after the capture that made it is finished with it, and lets it go when a later frame replaces it; shown(false) stops. With nobody drawing, a capture's target is released the moment its capture is done.

The release path asks retains(rtHandle) before destroying a target, which is how a held frame survives its own capture. capture.shared.releaseFrame is the one place that asks.