Emil
22012c1a80
4.2 KiB
Developer diagnostics
The optional Dear ImGui overlay shows renderer counters inside the Editor. The Editor's normal interface remains the retained Faset UI. Enable the diagnostic build explicitly:
cmake --preset linux-debug -DFASET_DEBUG_IMGUI=ON
cmake --build --preset linux-debug --parallel 4
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. 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.
In GPU occlusion mode, enable Show HZB to inspect the current grayscale depth pyramid. The Mip slider selects a pyramid level; the preview starts at mip 3 to keep its readback small. A larger mip number shows coarser depth. The preview reads the HZB only while the panel and toggle are open, and only once per completed frame or mip change. Switching it off or closing the panel releases the preview; its GPU texture retires when the next frame begins. Opening diagnostics also enables readback of GPU visibility counters, which is disabled again when the panel closes. Disable the HZB preview for performance comparisons: its diagnostic copy and texture upload add GPU and CPU work. Freeze counters does not freeze the HZB image.
The Vulkan backend emits VK_EXT_debug_utils labels for ShadowMap, ForwardAndUI, Readback, and, when presenting, Presentation. A graphics capture tool that supports this extension can identify those command-buffer regions. Labels remain available without the Khronos validation layer when the extension is exposed; unsupported systems continue rendering and report labels unavailable. A submitted-label count confirms calls were emitted, not that an external capture tool was tested.
This module is disabled by default and is linked only to the graphical Editor and its dedicated test when enabled. Player and exported games do not link ImGui. No overlay control changes authoring documents, gameplay state or export settings.
Run ctest --test-dir build/linux-debug -R '^editor_debug_overlay$' --output-on-failure in an enabled build to check actual ImGui geometry/font rendering, F12 toggling, pointer isolation and restoration of the underlying frame. The regular renderer pixel test also verifies GPU labels and clipped UI triangles.