From f56f8d919172b928bb04912e2dce282353926763 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=A0=81=E5=86=9C=E9=98=BF=E6=A5=A0?=
 <zhangyuge946@163.com>
Date: Mon, 25 May 2026 23:06:00 +0800
Subject: [PATCH] =?UTF-8?q?=E5=A2=9E=E5=8A=A0=E9=93=B6=E6=B2=B3?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/constants/config.ts        | 14 +++++++
 src/utils/createTravelScene.ts | 71 ++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+)

diff --git a/src/constants/config.ts b/src/constants/config.ts
index 4b3db9e..725d300 100644
--- a/src/constants/config.ts
+++ b/src/constants/config.ts
@@ -64,6 +64,20 @@ export const APP_CONFIG = {
     pointerSmoothing: 0.08,
     maxOffset: 0.4,
   },
+  // Galaxy parameters for background spiral galaxy layer.
+  galaxy: {
+    count: 50000,
+    radius: 15,
+    branches: 20,
+    spin: 0.3,
+    randomness: 0.15,
+    randomnessPower: 6,
+    size: 0.008,
+    rotationSpeed: 0.001,
+    zPosition: -35,
+    insideColor: '#ff6030',
+    outsideColor: '#3861cbff',
+  },
   // Shared UI timings used by overlays and toolbars.
   ui: {
     overlayFadeMs: 320,
diff --git a/src/utils/createTravelScene.ts b/src/utils/createTravelScene.ts
index ed86bf5..21d8896 100644
--- a/src/utils/createTravelScene.ts
+++ b/src/utils/createTravelScene.ts
@@ -234,6 +234,17 @@ export function createTravelScene(container: HTMLElement): TravelSceneController
   const ambientLight = new THREE.AmbientLight('#d9efff', 0.45)
   scene.add(ambientLight)
 
+  const galaxyGroup = new THREE.Group()
+  galaxyGroup.position.z = APP_CONFIG.galaxy.zPosition
+  // Tilt the galaxy to give it a perspective view
+  galaxyGroup.rotation.x = Math.PI * 0.35
+  galaxyGroup.rotation.y = Math.PI * 0.15
+  scene.add(galaxyGroup)
+
+  // Create an inner group for the galaxy rotation to preserve the tilt
+  const galaxyInnerGroup = new THREE.Group()
+  galaxyGroup.add(galaxyInnerGroup)
+
   const starsGeometry = new THREE.BufferGeometry()
   const starPositions = new Float32Array(STAR_COUNT * 3)
   const starColors = new Float32Array(STAR_COUNT * 3)
@@ -382,6 +393,61 @@ export function createTravelScene(container: HTMLElement): TravelSceneController
     travelRoot.add(state.mesh)
   }
 
+  const galaxyGeometry = new THREE.BufferGeometry()
+  const galaxyPositions = new Float32Array(APP_CONFIG.galaxy.count * 3)
+  const galaxyColors = new Float32Array(APP_CONFIG.galaxy.count * 3)
+  const colorInside = new THREE.Color(APP_CONFIG.galaxy.insideColor)
+  const colorOutside = new THREE.Color(APP_CONFIG.galaxy.outsideColor)
+
+  for (let i = 0; i < APP_CONFIG.galaxy.count; i += 1) {
+    const i3 = i * 3
+    const radius = Math.random() * APP_CONFIG.galaxy.radius
+    const branchesAngle =
+      ((i % APP_CONFIG.galaxy.branches) / APP_CONFIG.galaxy.branches) * Math.PI * 2
+    const spinAngle = radius * APP_CONFIG.galaxy.spin
+
+    const mixedColor = colorInside.clone()
+    mixedColor.lerp(colorOutside, radius / APP_CONFIG.galaxy.radius)
+
+    const randomX =
+      Math.random() ** APP_CONFIG.galaxy.randomnessPower *
+      (Math.random() < 0.5 ? 1 : -1) *
+      APP_CONFIG.galaxy.randomness *
+      radius
+    const randomY =
+      Math.random() ** APP_CONFIG.galaxy.randomnessPower *
+      (Math.random() < 0.5 ? 1 : -1) *
+      APP_CONFIG.galaxy.randomness *
+      radius
+    const randomZ =
+      Math.random() ** APP_CONFIG.galaxy.randomnessPower *
+      (Math.random() < 0.5 ? 1 : -1) *
+      APP_CONFIG.galaxy.randomness *
+      radius
+
+    galaxyPositions[i3] = Math.cos(branchesAngle + spinAngle) * radius + randomX
+    galaxyPositions[i3 + 1] = Math.sin(branchesAngle + spinAngle) * radius + randomY
+    galaxyPositions[i3 + 2] = randomZ
+
+    galaxyColors[i3] = mixedColor.r
+    galaxyColors[i3 + 1] = mixedColor.g
+    galaxyColors[i3 + 2] = mixedColor.b
+  }
+
+  galaxyGeometry.setAttribute('position', new THREE.BufferAttribute(galaxyPositions, 3))
+  galaxyGeometry.setAttribute('color', new THREE.BufferAttribute(galaxyColors, 3))
+
+  const galaxyMaterial = new THREE.PointsMaterial({
+    size: APP_CONFIG.galaxy.size,
+    sizeAttenuation: true,
+    depthWrite: false,
+    blending: THREE.AdditiveBlending,
+    vertexColors: true,
+  })
+
+  const galaxyPoints = new THREE.Points(galaxyGeometry, galaxyMaterial)
+  galaxyInnerGroup.add(galaxyPoints)
+
   const clock = new THREE.Clock()
 
   const onResize = () => {
@@ -523,6 +589,8 @@ export function createTravelScene(container: HTMLElement): TravelSceneController
     updateStars(motionDelta)
     updateSmoke(motionDelta * 0.62, elapsed)
 
+    galaxyInnerGroup.rotation.z += APP_CONFIG.galaxy.rotationSpeed * currentSpeed
+
     travelRoot.rotation.z = pointerCurrent.x * 0.03
     travelRoot.position.x = -pointerCurrent.x * 0.8
     travelRoot.position.y = -pointerCurrent.y * 0.45
@@ -563,6 +631,9 @@ export function createTravelScene(container: HTMLElement): TravelSceneController
         travelRoot.remove(smokeState.mesh)
       }
 
+      galaxyGeometry.dispose()
+      galaxyMaterial.dispose()
+
       starsGeometry.dispose()
       starMaterial.dispose()
       smokeGeometry.dispose()