3dgs & ply support (#7602)

## Summary

integrated sparkjs https://sparkjs.dev/, built by [world labs
](https://www.worldlabs.ai/) to support 3dgs.

- Add 3D Gaussian Splatting (3DGS) support using @sparkjsdev/spark
library
- Add PLY file format support with multiple rendering engines
- Support new file formats: `.ply`, `.spz`, `.splat`, `.ksplat`
- Add PLY Engine setting with three options: `threejs` (mesh), `fastply`
(optimized ASCII point clouds), `sparkjs` (3DGS)
- Add `FastPLYLoader` for 4-5x faster ASCII PLY parsing
- Add `original(Advanced)` material mode for point cloud rendering with
THREE.Points

3dgs generated by https://marble.worldlabs.ai/

test ply file from:
1. made by https://github.com/PozzettiAndrea/ComfyUI-DepthAnythingV3
2. threejs offically repo

## Screenshots


https://github.com/user-attachments/assets/44e64d3e-b58d-4341-9a70-a9aa64801220



https://github.com/user-attachments/assets/76b0dfba-0c12-4f64-91cb-bfc5d672294d



https://github.com/user-attachments/assets/2a8bfe81-1fb2-44c4-8787-dff325369c61



https://github.com/user-attachments/assets/e4beecee-d7a2-40c9-97f7-79b09c60312d

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7602-3dgs-ply-support-2cd6d73d3650814098fcea86cfaf747d)
by [Unito](https://www.unito.io)

src/components/load3d/Load3D.vue

@@ -22,6 +22,8 @@
         v-model:model-config="modelConfig"
         v-model:camera-config="cameraConfig"
         v-model:light-config="lightConfig"
+        :is-splat-model="isSplatModel"
+        :is-ply-model="isPlyModel"
         @update-background-image="handleBackgroundImageUpdate"
         @export-model="handleExportModel"
       />
@@ -109,6 +111,8 @@ const {
   // other state
   isRecording,
   isPreview,
+  isSplatModel,
+  isPlyModel,
   hasRecording,
   recordingDuration,
   animations,

src/components/load3d/Load3DControls.vue

@@ -47,6 +47,8 @@
         v-if="showModelControls"
         v-model:material-mode="modelConfig!.materialMode"
         v-model:up-direction="modelConfig!.upDirection"
+        :hide-material-mode="isSplatModel"
+        :is-ply-model="isPlyModel"
       />
 
       <CameraControls
@@ -85,6 +87,11 @@ import type {
   SceneConfig
 } from '@/extensions/core/load3d/interfaces'
 
+const { isSplatModel = false, isPlyModel = false } = defineProps<{
+  isSplatModel?: boolean
+  isPlyModel?: boolean
+}>()
+
 const sceneConfig = defineModel<SceneConfig>('sceneConfig')
 const modelConfig = defineModel<ModelConfig>('modelConfig')
 const cameraConfig = defineModel<CameraConfig>('cameraConfig')
@@ -101,6 +108,10 @@ const categoryLabels: Record<string, string> = {
 }
 
 const availableCategories = computed(() => {
+  if (isSplatModel) {
+    return ['scene', 'model', 'camera']
+  }
+
   return ['scene', 'model', 'camera', 'light', 'export']
 })
 

src/components/load3d/Load3dViewerContent.vue

@@ -46,6 +46,8 @@
             <ModelControls
               v-model:up-direction="viewer.upDirection.value"
               v-model:material-mode="viewer.materialMode.value"
+              :hide-material-mode="viewer.isSplatModel.value"
+              :is-ply-model="viewer.isPlyModel.value"
             />
           </div>
 
@@ -56,13 +58,13 @@
             />
           </div>
 
-          <div class="space-y-4 p-2">
+          <div v-if="!viewer.isSplatModel.value" class="space-y-4 p-2">
             <LightControls
               v-model:light-intensity="viewer.lightIntensity.value"
             />
           </div>
 
-          <div class="space-y-4 p-2">
+          <div v-if="!viewer.isSplatModel.value" class="space-y-4 p-2">
             <ExportControls @export-model="viewer.exportModel" />
           </div>
         </div>

src/components/load3d/controls/ModelControls.vue

@@ -28,7 +28,7 @@
       </div>
     </div>
 
-    <div class="show-material-mode relative">
+    <div v-if="!hideMaterialMode" class="show-material-mode relative">
       <Button
         class="p-button-rounded p-button-text"
         @click="toggleMaterialMode"
@@ -71,6 +71,11 @@ import type {
 } from '@/extensions/core/load3d/interfaces'
 import { t } from '@/i18n'
 
+const { hideMaterialMode = false, isPlyModel = false } = defineProps<{
+  hideMaterialMode?: boolean
+  isPlyModel?: boolean
+}>()
+
 const materialMode = defineModel<MaterialMode>('materialMode')
 const upDirection = defineModel<UpDirection>('upDirection')
 
@@ -95,6 +100,11 @@ const materialModes = computed(() => {
     //'depth' disable for now
   ]
 
+  // Only show pointCloud mode for PLY files (point cloud rendering)
+  if (isPlyModel) {
+    modes.splice(1, 0, 'pointCloud')
+  }
+
   return modes
 })
 

src/components/load3d/controls/viewer/ViewerModelControls.vue

@@ -10,7 +10,7 @@
       />
     </div>
 
-    <div>
+    <div v-if="!hideMaterialMode">
       <label>{{ $t('load3d.materialMode') }}</label>
       <Select
         v-model="materialMode"
@@ -32,6 +32,11 @@ import type {
 } from '@/extensions/core/load3d/interfaces'
 import { t } from '@/i18n'
 
+const { hideMaterialMode = false, isPlyModel = false } = defineProps<{
+  hideMaterialMode?: boolean
+  isPlyModel?: boolean
+}>()
+
 const upDirection = defineModel<UpDirection>('upDirection')
 const materialMode = defineModel<MaterialMode>('materialMode')
 
@@ -46,10 +51,22 @@ const upDirectionOptions = [
 ]
 
 const materialModeOptions = computed(() => {
-  return [
-    { label: t('load3d.materialModes.original'), value: 'original' },
+  const options = [
+    { label: t('load3d.materialModes.original'), value: 'original' }
+  ]
+
+  if (isPlyModel) {
+    options.push({
+      label: t('load3d.materialModes.pointCloud'),
+      value: 'pointCloud'
+    })
+  }
+
+  options.push(
     { label: t('load3d.materialModes.normal'), value: 'normal' },
     { label: t('load3d.materialModes.wireframe'), value: 'wireframe' }
-  ]
+  )
+
+  return options
 })
 </script>