You're right — the telemetry path itself was contributing to perceived
browser lag, not just the GPU work. Two specific sources removed:
render/mod.rs::rebuild_chunk:
- Per-chunk log::info!("rebuild_chunk {coord}: {ms}ms ...") fired
~289 times during world init, plus on every edit. Chrome's console
buffer accumulates these and DevTools recalcs on each new line.
Removed entirely. The bench toggles + FPS HUD already give us the
measurement signal; per-chunk timing was noise once verified.
web/main.js setupFpsHud:
- Was a 5 Hz setInterval that did `el.textContent = ...` and two
`classList.toggle` calls each tick (15 DOM writes/sec). Now:
* Polls at 1 Hz (the EMA already smooths)
* Only writes textContent when the displayed string actually
changes (skip is the common case once stabilized)
* Only writes class when the tier (green/warn/bad) crosses
a threshold
Same readout, ~15× fewer DOM writes.
web/main.js setupStatusLoop (HP bar):
- Same dedupe pattern. 10 Hz polling, but DOM writes only when
hp or alive changes from the last sample. Was firing 3 style
writes per tick unconditionally; now zero in steady state.
No functionality changes — every telemetry getter, every bench
toggle, every test-harness export still works (just verified via
the 18-check functional contract suite).
Wasm release built; tests 63/63 pass.
The features added in Rounds A–D were correct but expensive. The hot
path per frame was sky_color() called from apply_fog for EVERY distant
pixel — 4-octave cloud fbm + star hash + sun/moon disc per fragment,
hundreds of thousands of pixels per frame. Profile-driven cuts that
keep all features but stop paying for them in the wrong places:
1. apply_fog now mixes terrain toward sky_dome (cheap gradient) not
sky_color (gradient + clouds + sun + moon + stars). Distant terrain
still fades to the right-direction sky color at every time of day;
the per-pixel cost drops by ~80%. Full sky_color still runs for
the SKY BACKGROUND pass where it's actually paid for.
2. Sky pipeline draws AFTER terrain with depth_compare = LessEqual.
The full-screen sky was previously written first then over-painted
by terrain — sky's expensive fragment shader ran on every screen
pixel. Now it only runs on pixels with no terrain in front of them
(depth = 1.0 cleared), which on most views is 30–60% of the screen
instead of 100%.
3. fbm2 reduced from 4 → 3 octaves. Negligible visual change at the
scales we sample, ~25% cheaper per cloud-pixel.
4. Cloud branch skips entirely when day_strength < 0.05 (full night).
Clouds invisible at night anyway, fbm + smoothstep + mix skipped.
5. In-game FPS HUD (top-right corner):
- Telemetry struct gains frame_dt_ms (EMA-smoothed in app.rs
with coefficient 0.85 so the number is readable, not flickery).
- wasm bridge: get_frame_dt_ms().
- main.js setupFpsHud() polls it at 5Hz, color-coded:
green ≤ 18ms (≥55fps), amber 18-33ms, red beyond.
- Reads what THE GAME measures, not the browser's
requestAnimationFrame which gets throttled to 1 Hz on
unfocused windows.
No features removed. God rays, FXAA, ACES tonemap, bounce baking,
specular materials, leaf translucency — all still there. Tests:
63 passing. Wasm release clean.
run.sh:
- phase() wrapper logs elapsed seconds per build step.
- Tracks total build+startup at the end.
- Output is "==> phase / [Ns] phase" so the slow steps are obvious.
test/run.py:
- Per-step time.perf_counter() around each scenario step.
- "slowest steps" summary printed at the end so the worst
offenders are immediately visible.
- Total wall-clock time at scenario end.
src/render/mod.rs:
- browser_now() helper: web_sys::performance().now() on wasm,
Instant-based on native. Monotonic ms timestamps for tick/toc.
- Renderer::rebuild_chunk wraps build_chunk_mesh in a t0/t1
measurement and logs anything over 5ms with vertex/index counts.
Surfaces sky_visibility cost in the browser console.
web/main.js:
- Exposes window.voxel_game = wasm after init so the test
harness can drive scenarios declaratively (set_scene_time,
teleport, look_at, get_position, etc.).
src/shader.wgsl:
- Fix duplicate `let to_eye` declaration introduced in Round D
(specular's normalized to_eye conflicted with fog's raw version).
Renamed fog's local to_eye_raw. The test harness caught this
immediately — first WGSL compile error, first scenario run.
Findings from running scenarios/lighting-times-of-day.yaml:
- 289 chunks × ~100ms avg = ~29s mesh-build on main thread.
- Page-ready latency dominated by this. window.voxel_game appears
almost immediately (init resolves before chunks build), but
the world is invisible until meshes are uploaded.
- sky_visibility (8 cosine rays × HashMap voxel lookups) is the
hot path inside build_chunk_mesh.
Next: make chunk-mesh build progressive (one or two chunks per tick
instead of all up-front), so the world becomes visible immediately
and pops in over a few seconds.
- Greedy meshing now bakes per-vertex AO with 4-corner sampling and an
anisotropic-diagonal split when corner AO disagrees.
- WGSL: extracted sky_dome() for hemisphere ambient sampling so vertical
faces match the sun-side sky tint at day; ambient_strength mixed by
day strength instead of a flat constant.
- Step-1 post pipeline: render scene into an offscreen color texture,
pass-through to the surface. Foundation for FXAA/shafts that will
follow.
- Input bug: merge_held() now recomputes per tick from sticky keyboard +
live touch bridge, so releasing the joystick actually stops the
player (previous OR-into-self bug ate playtests).
- Touch UI hit-zones reordered (menu/hotbar above the joystick z-index);
hotbar widened to 10 slots with tap-to-select on mobile.
- find_safe_spawn anchors on natural_surface_y so spawn is deterministic
from noise — towers built at spawn no longer climb the spawn point.
- move_axis is sub-stepped (0.45-block max) so high-velocity falls can't
teleport the player inside terrain.
