Report effective visibility and stable GPU instance identity

docs/manual/editor/diagnostics.md

@@ -10,7 +10,7 @@ build/linux-debug/faset_editor --project examples/projects/collect-3d --gui
 
 On Windows, use `windows-debug` for both presets and `build/windows-debug/faset_editor.exe`. Press **F12** to show or hide the panel. Drag its title bar to move it; **Freeze counters** holds a completed-frame sample for inspection. Closing the panel does not stop rendering. Pointer gestures inside the overlay are kept out of the authoring UI.
 
-Use the **Visibility** selector to compare **Direct**, **GPU frustum**, and **GPU occlusion** on the same open scene. This is a live renderer setting for the Editor viewport; it does not change the scene or exported game. The selected mode is independent of **Freeze counters**. The counters describe the previous completed frame, so render one more frame after changing modes before reading them. **Path: active** under GPU visibility confirms that the GPU path actually ran; a selected GPU mode by itself is not evidence that it ran.
+Use the **Visibility** selector to compare **Direct**, **GPU frustum**, and **GPU occlusion** on the same open scene. This is a live renderer setting for the Editor viewport; it does not change the scene or exported game. The selected mode is independent of **Freeze counters**. The counters describe the previous completed frame, so render one more frame after changing modes before reading them. **Effective path** names the algorithm that actually ran. A **Fallback from** line appears when device or target capabilities prevent the selected mode; for example, GPU occlusion may use GPU frustum if HZB is unavailable.
 
 The panel reports the previous completed frame: renderer wall time, GPU timestamp time where available, synchronous readback time, draw calls, packed vertices, culled meshes, textures, explicit Vulkan allocation sizes, actual validation availability/errors, and GPU pass-label count. It also shows whether GPU visibility ran, submitted indirect bins, visible instances, frustum rejects, deferred and post-pass visible instances, HZB history validity, counts per prepared LOD level, and GPU pass timings where available. GPU counts are explicitly marked unavailable until the first frame rendered with diagnostics open; only a displayed zero is a measured zero. **Previous HZB history: invalid** is expected after a camera cut or resize until compatible depth history is available. A current HZB preview can still exist after that first frame because it was built from the current depth. Renderer wall time includes waiting for GPU work; it is not thread CPU usage. Memory excludes driver-internal allocations. The overlay itself adds drawing work, so hide it for a baseline performance measurement.
 

docs/manual/editor/profiling.md

@@ -80,10 +80,11 @@ bounded run:
 ```
 
 Accepted values are `direct`, `gpu-frustum`, and `gpu-occlusion`; Direct is the
-default. The profile records the requested `visibility_mode` and each frame's
-`gpu_visibility_active` state. Check that state when interpreting a GPU run: a
-requested mode can fall back if the required device profile is unavailable. The
-Editor reports the same distinction as **Path: active**. See
+default. The profile records the requested `visibility_mode`, the run's and each
+frame's `effective_visibility_mode`, and each frame's `gpu_visibility_active` state.
+Compare requested and effective modes before interpreting a GPU run: a missing GPU
+profile falls back to Direct, while missing HZB can reduce GPU occlusion to GPU
+frustum. The Editor shows the **Effective path** and any **Fallback from** line. See
 [Diagnostics](diagnostics.md) for the counters and HZB preview.
 
 For a repeatable offscreen comparison, build and run the P2 benchmark harness: