//#region src/debug/detectGpuTiming.d.ts
/**
 * Decide whether the current renderer is actually capable of emitting
 * GPU timestamps — *not* just "the user asked for them via
 * `trackTimestamp: true`".
 *
 * This is the single source of truth for the `gpuModeEnabled` env flag
 * shipped to consumers AND for the producer's per-frame decision to
 * include a `gpuMs` ring in the stats payload. Mismatching those two
 * is what previously caused the regression: producer shipped a
 * forward-filled zero buffer while consumers happily rendered it.
 *
 * The probe is cheap (one string compare + a property access). Call it
 * every frame rather than caching — `trackTimestamp` flips during
 * three.js's `init()`, so any value cached before the device is ready
 * is stale.
 *
 * Backend-specific signals:
 *
 *   - WebGL2: three exposes the `EXT_disjoint_timer_query_webgl2`
 *     extension as `backend.disjoint`. Non-null = present.
 *   - WebGPU: after `init()`, three rewrites
 *     `backend.trackTimestamp = trackTimestamp && hasFeature('timestamp-query')`.
 *     We trust that as authoritative — but additionally probe the
 *     device's features when present so the answer is right *before*
 *     init lands too.
 */
interface GpuTimingProbeBackend {
  trackTimestamp?: boolean;
  constructor?: {
    name?: string;
  };
  /** WebGL2: present iff `EXT_disjoint_timer_query_webgl2` was negotiated. */
  disjoint?: unknown;
  /** WebGPU: the live `GPUDevice` once init has resolved. */
  device?: unknown;
}
declare function detectGpuTimingActive(backend: GpuTimingProbeBackend | undefined): boolean;
/**
 * Decide what to write to `backend.trackTimestamp` this frame.
 *
 * Devtools owns GPU-timestamp sampling and toggles it *live*: on while a
 * consumer is subscribed to stats (the dashboard / pane is expanded), off
 * otherwise (collapsed). Turning it off makes three stop issuing timestamp
 * queries, so the query pool never fills with entries nobody drains.
 *
 *   - `null`  → backend not attached yet; leave the flag alone, retry next frame.
 *   - `false` → timing not wanted, OR wanted but the device can't do it
 *               (post-init WebGPU without the `timestamp-query` feature, e.g.
 *               Safari). Either way three should not emit queries.
 *   - `true`  → wanted and either the feature is present, or the device isn't
 *               ready yet (optimistic — three's `init()` AND-gates the flag
 *               against feature support, so an unsupported backend
 *               self-corrects to `false` on the next frame). WebGL backends
 *               (no `GPUDevice`) take this path; the resolve side is still
 *               gated by `detectGpuTimingActive`'s `disjoint` check.
 */
declare function resolveTrackTimestamp(want: boolean, backend: GpuTimingProbeBackend | undefined): boolean | null;
//#endregion
export { GpuTimingProbeBackend, detectGpuTimingActive, resolveTrackTimestamp };
//# sourceMappingURL=detectGpuTiming.d.ts.map