feat: 3 scene rendering setup

apps/viewer/src/viewerSystemLayer.ts

@@ -0,0 +1,47 @@
+import * as THREE from "three";
+import type { Selectable } from "./viewerTypes";
+
+/**
+ * System rendering layer.
+ * Scene coordinate unit: km * DISPLAY_UNITS_PER_KILOMETER * ACTIVE_SYSTEM_DETAIL_SCALE.
+ * Camera far plane covers a solar system.
+ * Only the active system's objects are visible; inactive system objects are hidden in place.
+ */
+export class SystemLayer {
+  readonly scene = new THREE.Scene();
+  readonly camera = new THREE.PerspectiveCamera(50, 1, 0.1, 50000);
+
+  readonly celestialGroup = new THREE.Group();
+  readonly nodeGroup = new THREE.Group();
+  readonly stationGroup = new THREE.Group();
+  readonly claimGroup = new THREE.Group();
+  readonly constructionSiteGroup = new THREE.Group();
+  readonly shipGroup = new THREE.Group();
+
+  readonly selectableTargets = new Map<THREE.Object3D, Selectable>();
+
+  constructor() {
+    this.scene.add(new THREE.AmbientLight(0x90a6c0, 0.55));
+    const keyLight = new THREE.DirectionalLight(0xdcecff, 1.3);
+    keyLight.position.set(1000, 1200, 800);
+    this.scene.add(keyLight);
+    this.scene.add(
+      this.celestialGroup,
+      this.nodeGroup,
+      this.stationGroup,
+      this.claimGroup,
+      this.constructionSiteGroup,
+      this.shipGroup,
+    );
+  }
+
+  updateCamera(systemFocus: THREE.Vector3, orbitOffset: THREE.Vector3) {
+    this.camera.position.copy(systemFocus).add(orbitOffset);
+    this.camera.lookAt(systemFocus);
+  }
+
+  onResize(aspect: number) {
+    this.camera.aspect = aspect;
+    this.camera.updateProjectionMatrix();
+  }
+}