feat: build procedural lifecycle-safe drive scene

src/scene/render-quality.ts

@@ -0,0 +1,29 @@
+import type { LiveQualityTier } from '@/scene/types';
+
+export interface RenderQualitySettings {
+  pixelRatio: number;
+  terrainSegments: number;
+  particleCount: number;
+  postEffects: boolean;
+}
+
+const settings: Readonly<Record<LiveQualityTier, Omit<RenderQualitySettings, 'pixelRatio'> & { dprCap: number }>> = {
+  high: { dprCap: 2, terrainSegments: 96, particleCount: 384, postEffects: true },
+  medium: { dprCap: 1.5, terrainSegments: 64, particleCount: 192, postEffects: true },
+  low: { dprCap: 1.25, terrainSegments: 32, particleCount: 64, postEffects: false },
+};
+
+export function renderQualityFor(
+  tier: LiveQualityTier,
+  devicePixelRatio: number,
+  mobileOrTablet: boolean,
+): RenderQualitySettings {
+  const selected = settings[tier];
+  const finiteDpr = Number.isFinite(devicePixelRatio) ? Math.max(1, devicePixelRatio) : 1;
+  return {
+    pixelRatio: Math.min(finiteDpr, selected.dprCap, mobileOrTablet ? 1.5 : 2),
+    terrainSegments: selected.terrainSegments,
+    particleCount: selected.particleCount,
+    postEffects: selected.postEffects,
+  };
+}