fix: 3D asset disappears when switching to image output in app mode

- Add cleanup on unmount to prevent WebGL context leaks
- Add cleanup before re-init to prevent stacked Load3d instances
- Use flush:'post' watch to ensure DOM is ready before init
- Add :key on Preview3d for fresh instance on URL change

src/renderer/extensions/linearMode/MediaOutputPreview.vue

@@ -49,6 +49,7 @@ const attrs = useAttrs()
   />
   <Preview3d
     v-else-if="getMediaType(output) === '3d'"
+    :key="output.url"
     :class="attrs.class as string"
     :model-url="output.url"
   />

src/renderer/extensions/linearMode/Preview3d.test.ts

@@ -0,0 +1,120 @@
+import { mount } from '@vue/test-utils'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { nextTick } from 'vue'
+
+const initializeStandaloneViewer = vi.fn()
+const cleanup = vi.fn()
+
+vi.mock('@/composables/useLoad3dViewer', () => ({
+  useLoad3dViewer: () => ({
+    initializeStandaloneViewer,
+    cleanup,
+    handleMouseEnter: vi.fn(),
+    handleMouseLeave: vi.fn(),
+    handleResize: vi.fn(),
+    handleBackgroundImageUpdate: vi.fn(),
+    exportModel: vi.fn(),
+    handleSeek: vi.fn(),
+    isSplatModel: false,
+    isPlyModel: false,
+    hasSkeleton: false,
+    animations: [],
+    playing: false,
+    selectedSpeed: 1,
+    selectedAnimation: 0,
+    animationProgress: 0,
+    animationDuration: 0
+  })
+}))
+
+vi.mock('@/components/load3d/Load3DControls.vue', () => ({
+  default: { template: '<div />' }
+}))
+
+vi.mock('@/components/load3d/controls/AnimationControls.vue', () => ({
+  default: { template: '<div />' }
+}))
+
+describe('Preview3d', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  afterEach(() => {
+    vi.restoreAllMocks()
+  })
+
+  async function mountPreview3d(
+    modelUrl = 'http://localhost/view?filename=model.glb'
+  ) {
+    const wrapper = mount(
+      (await import('@/renderer/extensions/linearMode/Preview3d.vue')).default,
+      { props: { modelUrl } }
+    )
+    await nextTick()
+    await nextTick()
+    return wrapper
+  }
+
+  it('initializes the viewer on mount', async () => {
+    await mountPreview3d()
+
+    expect(initializeStandaloneViewer).toHaveBeenCalledOnce()
+    expect(initializeStandaloneViewer).toHaveBeenCalledWith(
+      expect.any(HTMLElement),
+      'http://localhost/view?filename=model.glb'
+    )
+  })
+
+  it('cleans up the viewer on unmount', async () => {
+    const wrapper = await mountPreview3d()
+    cleanup.mockClear()
+
+    wrapper.unmount()
+
+    expect(cleanup).toHaveBeenCalledOnce()
+  })
+
+  it('cleans up before reinitializing when modelUrl changes', async () => {
+    const wrapper = await mountPreview3d('http://localhost/view?filename=a.glb')
+    vi.clearAllMocks()
+
+    await wrapper.setProps({
+      modelUrl: 'http://localhost/view?filename=b.glb'
+    })
+    await nextTick()
+    await nextTick()
+
+    const cleanupOrder = cleanup.mock.invocationCallOrder[0]
+    const initOrder = initializeStandaloneViewer.mock.invocationCallOrder[0]
+    expect(cleanupOrder).toBeLessThan(initOrder)
+    expect(initializeStandaloneViewer).toHaveBeenCalledWith(
+      expect.any(HTMLElement),
+      'http://localhost/view?filename=b.glb'
+    )
+  })
+
+  it('reinitializes correctly after unmount and remount', async () => {
+    const url = 'http://localhost/view?filename=model.glb'
+
+    const wrapper1 = await mountPreview3d(url)
+    expect(initializeStandaloneViewer).toHaveBeenCalledTimes(1)
+
+    cleanup.mockClear()
+    wrapper1.unmount()
+    expect(cleanup).toHaveBeenCalledOnce()
+
+    vi.clearAllMocks()
+
+    const wrapper2 = await mountPreview3d(url)
+    expect(initializeStandaloneViewer).toHaveBeenCalledTimes(1)
+    expect(initializeStandaloneViewer).toHaveBeenCalledWith(
+      expect.any(HTMLElement),
+      url
+    )
+
+    cleanup.mockClear()
+    wrapper2.unmount()
+    expect(cleanup).toHaveBeenCalledOnce()
+  })
+})

src/renderer/extensions/linearMode/Preview3d.vue

@@ -13,10 +13,19 @@ const containerRef = useTemplateRef('containerRef')
 
 const viewer = ref(useLoad3dViewer())
 
-watch([containerRef, () => modelUrl], async () => {
-  if (!containerRef.value || !modelUrl) return
+watch(
+  [containerRef, () => modelUrl],
+  async () => {
+    if (!containerRef.value || !modelUrl) return
 
-  await viewer.value.initializeStandaloneViewer(containerRef.value, modelUrl)
+    viewer.value.cleanup()
+    await viewer.value.initializeStandaloneViewer(containerRef.value, modelUrl)
+  },
+  { flush: 'post' }
+)
+
+onUnmounted(() => {
+  viewer.value.cleanup()
 })
 
 onUnmounted(() => {