replace day/night cycle with a binary light/dark mode tied to UserSettings

The cycling sun/moon animation was distracting and not a fan favorite.
Drops the cycle path entirely — RenderSettings.dayNight.mode is now
"light" | "dark", and the cycle-only fields (cycleTicks, startPhase,
noonHold, nightHold) plus the passEnabled.dayNight toggle are gone.
getAmbient is a one-liner. The in-game mode follows the existing
darkMode UserSetting (same one that drives the page-level CSS class);
ClientGameRunner applies it on startup and on the per-key change event.

src/client/ClientGameRunner.ts

@@ -29,7 +29,11 @@ import {
 } from "../core/game/GameUpdates";
 import { GameView, PlayerView } from "../core/game/GameView";
 import { loadTerrainMap, TerrainMapData } from "../core/game/TerrainMapLoader";
-import { UserSettings } from "../core/game/UserSettings";
+import {
+  DARK_MODE_KEY,
+  USER_SETTINGS_CHANGED_EVENT,
+  UserSettings,
+} from "../core/game/UserSettings";
 import { WorkerClient } from "../core/worker/WorkerClient";
 import { getPersistentID } from "./Auth";
 import {
@@ -429,6 +433,18 @@ async function createClientGame(
     const { view, glCanvas, cachedWebGLFrameCallback } =
       createWebGLView(gameMap);
 
+    // Bind the WebGL renderer's day/night mode to the existing darkMode
+    // UserSetting so the in-game map matches the rest of the UI. Initial
+    // apply + live updates via the per-key settings-changed event.
+    const applyDayNightMode = (isDark: boolean): void => {
+      view.getSettings().dayNight.mode = isDark ? "dark" : "light";
+    };
+    applyDayNightMode(userSettings.darkMode());
+    globalThis.addEventListener(
+      `${USER_SETTINGS_CHANGED_EVENT}:${DARK_MODE_KEY}`,
+      (e) => applyDayNightMode((e as CustomEvent<string>).detail === "true"),
+    );
+
     const gameRenderer = createRenderer(
       inputOverlay,
       gameView,

src/client/render/gl/debug/layout.ts

@@ -18,7 +18,6 @@ export function buildTree(s: RenderSettings, d: RenderSettings): DebugNode[] {
       toggle(s.passEnabled, "railroad", d.passEnabled),
       toggle(s.passEnabled, "fx", d.passEnabled),
       toggle(s.passEnabled, "bar", d.passEnabled),
-      toggle(s.passEnabled, "dayNight", d.passEnabled),
       toggle(s.passEnabled, "nameDebug", d.passEnabled, "Name Debug Boxes"),
     ]),
 
@@ -50,25 +49,7 @@ export function buildTree(s: RenderSettings, d: RenderSettings): DebugNode[] {
     ]),
 
     folder("Day / Night", [
-      select(
-        s.dayNight,
-        "mode",
-        d.dayNight,
-        ["light", "dark", "cycle"],
-        "Mode",
-      ),
-      slider(s.dayNight, "cycleTicks", d.dayNight, 60, 6000, 10),
-      slider(
-        s.dayNight,
-        "startPhase",
-        d.dayNight,
-        0,
-        1,
-        0.01,
-        "Start Phase (0=noon)",
-      ),
-      slider(s.dayNight, "noonHold", d.dayNight, 0, 1, 0.01, "Noon Hold"),
-      slider(s.dayNight, "nightHold", d.dayNight, 0, 1, 0.01, "Night Hold"),
+      select(s.dayNight, "mode", d.dayNight, ["light", "dark"], "Mode"),
       slider(s.dayNight, "nightAmbient", d.dayNight, 0, 1, 0.01),
       slider(s.dayNight, "dayAmbient", d.dayNight, 0, 1, 0.01),
       slider(s.dayNight, "falloffPower", d.dayNight, 0.5, 5, 0.1),

src/client/render/gl/passes/night-composite-pass.ts

@@ -15,11 +15,6 @@ import { createFullscreenQuad, createProgram } from "../utils/gl-utils";
 import compositeFragSrc from "../shaders/day-night/composite.frag.glsl?raw";
 import fullscreenVertSrc from "../shaders/shared/fullscreen.vert.glsl?raw";
 
-function smoothstep(edge0: number, edge1: number, x: number): number {
-  const t = Math.max(0, Math.min(1, (x - edge0) / (edge1 - edge0)));
-  return t * t * (3 - 2 * t);
-}
-
 export class NightCompositePass {
   private gl: WebGL2RenderingContext;
   private settings: RenderSettings;
@@ -51,38 +46,9 @@ export class NightCompositePass {
   // Ambient
   // -------------------------------------------------------------------------
 
-  getAmbient(tick: number): number {
+  getAmbient(): number {
     const dn = this.settings.dayNight;
-
-    if (dn.mode === "light") return dn.dayAmbient;
-    if (dn.mode === "dark") return dn.nightAmbient;
-
-    // Normalize phase to [0, 1), 0 = noon
-    const phase = (((tick / dn.cycleTicks + dn.startPhase) % 1) + 1) % 1;
-
-    // Clamp holds so they never exceed the full cycle
-    const noonHold = Math.min(dn.noonHold, 1);
-    const nightHold = Math.min(dn.nightHold, Math.max(0, 1 - noonHold));
-    const halfTransition = (1 - noonHold - nightHold) / 2;
-
-    // Region boundaries (all in [0, 1))
-    const duskStart = noonHold / 2;
-    const duskEnd = duskStart + halfTransition; // = 0.5 - nightHold/2
-    const nightEnd = duskEnd + nightHold; // = 0.5 + nightHold/2
-    const dawnEnd = nightEnd + halfTransition; // = 1   - noonHold/2
-
-    let t: number;
-    if (phase < duskStart || phase >= dawnEnd) {
-      t = 1; // noon hold
-    } else if (phase < duskEnd) {
-      t = smoothstep(duskEnd, duskStart, phase); // day → night
-    } else if (phase < nightEnd) {
-      t = 0; // midnight hold
-    } else {
-      t = smoothstep(nightEnd, dawnEnd, phase); // night → day
-    }
-
-    return dn.nightAmbient + (dn.dayAmbient - dn.nightAmbient) * t;
+    return dn.mode === "dark" ? dn.nightAmbient : dn.dayAmbient;
   }
 
   // -------------------------------------------------------------------------
@@ -90,12 +56,12 @@ export class NightCompositePass {
   // -------------------------------------------------------------------------
 
   /** Pure combiner — receives captured scene + lightmap textures, outputs to screen. */
-  draw(tick: number, sceneTex: WebGLTexture, lightmapTex: WebGLTexture): void {
+  draw(sceneTex: WebGLTexture, lightmapTex: WebGLTexture): void {
     const gl = this.gl;
     gl.disable(gl.BLEND);
 
     gl.useProgram(this.compositeProg);
-    gl.uniform1f(this.uCompositeAmbient, this.getAmbient(tick));
+    gl.uniform1f(this.uCompositeAmbient, this.getAmbient());
 
     gl.activeTexture(gl.TEXTURE0);
     gl.bindTexture(gl.TEXTURE_2D, sceneTex);

src/client/render/gl/render-settings.json

@@ -9,7 +9,6 @@
     "railroad": true,
     "fx": true,
     "bar": true,
-    "dayNight": true,
     "nameDebug": false
   },
   "falloutBloom": {
@@ -34,11 +33,7 @@
     "heatDecayPerTick": 1
   },
   "dayNight": {
-    "mode": "cycle",
-    "cycleTicks": 6000,
-    "startPhase": 0,
-    "noonHold": 0.25,
-    "nightHold": 0.1,
+    "mode": "light",
     "nightAmbient": 0.15,
     "dayAmbient": 1,
     "falloffPower": 2,

src/client/render/gl/render-settings.ts

@@ -11,7 +11,6 @@ export interface RenderSettings {
     railroad: boolean;
     fx: boolean;
     bar: boolean;
-    dayNight: boolean;
     nameDebug: boolean;
   };
   falloutBloom: {
@@ -36,11 +35,7 @@ export interface RenderSettings {
     heatDecayPerTick: number;
   };
   dayNight: {
-    mode: "light" | "dark" | "cycle";
-    cycleTicks: number;
-    startPhase: number; // 0–1, where 0 = noon, 0.25 = dusk, 0.5 = midnight, 0.75 = dawn
-    noonHold: number; // fraction of cycle held at full brightness (0–1)
-    nightHold: number; // fraction of cycle held at full darkness  (0–1); noonHold+nightHold ≤ 1
+    mode: "light" | "dark";
     nightAmbient: number;
     dayAmbient: number;
     falloffPower: number;

src/client/render/gl/renderer.ts

@@ -135,7 +135,6 @@ export class GPURenderer {
 
   private animId: number | null = null;
   private frameTick = 0;
-  private gameTick = 0;
   private mapW = 0;
   private mapH = 0;
 
@@ -598,7 +597,6 @@ export class GPURenderer {
   updateUnits(units: Map<number, UnitState>, gameTick: number): void {
     this.lastUnits = units;
     this.frameTick++;
-    this.gameTick = gameTick;
     this.unitPass.updateUnits(units, this.frameTick);
     this.barPass.updateBars(units, this.lastStructures, gameTick);
     this.pointLightPass.updateLights(units);
@@ -1015,7 +1013,7 @@ export class GPURenderer {
       );
       const lightTex = this.lightmapPass.draw(cam, cw, ch);
       toScreen(this.gl, cw, ch, () =>
-        this.nightCompositePass.draw(this.gameTick, sceneTex, lightTex),
+        this.nightCompositePass.draw(sceneTex, lightTex),
       );
     } else {
       toScreen(this.gl, cw, ch, () => this.drawBaseLayer(cam));
@@ -1025,11 +1023,7 @@ export class GPURenderer {
   }
 
   private isNightActive(): boolean {
-    const mode = this.settings.dayNight.mode;
-    return (
-      mode === "dark" ||
-      (mode === "cycle" && this.settings.passEnabled.dayNight)
-    );
+    return this.settings.dayNight.mode === "dark";
   }
 
   private resizeSceneTargetIfNeeded(cw: number, ch: number): void {
@@ -1099,10 +1093,7 @@ export class GPURenderer {
 
     if (this.gridView) this.coordinateGridPass.draw(cam, zoom);
     if (pe.name && !this.gridView)
-      this.namePass.draw(
-        cam,
-        this.nightCompositePass.getAmbient(this.gameTick),
-      );
+      this.namePass.draw(cam, this.nightCompositePass.getAmbient());
 
     this.radialMenuPass.draw();