totk-pc-recomp/runtime/flight.h

// TOTK_FLIGHT=1 flight recorder (flight.c): the last frames' timing and event counts plus a thumbnail each, written to
// disk on F8 or after a slow frame, so a glitch or stutter seen in play can be read after the fact.
#pragma once
#include <stdint.h>

#define FLIGHT_THUMB_W 320
#define FLIGHT_THUMB_H 180

extern int flight_on;   // TOTK_FLIGHT=1, set once by flight_init before the first present

void flight_init(void);   // prof_start calls it
// perf_present, once per present on the render thread: the interval since the previous present, the render thread's
// blocked time per PERF_* kind in this frame, and the running PERF_CNT_* totals.
void flight_frame(uint64_t frame, uint64_t now_ns, uint64_t interval_ns, const uint64_t blocked_ns[],
                  const volatile int64_t counts[]);

// gfx_window.c: the present thread blits every presented frame into a host-visible ring of n thumbnails.
void vk_thumbs_enable(int n);            // before the first present; n slots of FLIGHT_THUMB_W x FLIGHT_THUMB_H
void vk_thumbs_frame(uint64_t frame);    // the present thread names the frame of the vk_present_image call that follows
// Copies frame's thumbnail as RGBA when the ring still holds it complete; 0 when it was never written, is still in
// flight or was overwritten. Takes the present lock for one slot copy (about 20 us); any thread.
int vk_thumbs_read(uint64_t frame, uint8_t *rgba);