Add legacy support for loading tonemap settings and camera properties

examples/tweakpane-editor/script.ts

         rgbm: true,
         dropzone: {
             addOptions: {
-                clearSceneObjects: false,
+                clearSceneObjects: false, // clear the scene before adding new objects on drop.
             },
         },
     })

src/assetmanager/IExporter.ts

     /**
      * Export and bundle the viewer config (scene settings).
      * only works for rootSceneModelRoot and supported only in GLTFExporter2 {@link GLTFExporter2Options.viewerConfig}
-     * @default true
+     * {@default true}
      */
     viewerConfig?: boolean,
 

src/core/camera/PerspectiveCamera2.ts

     }
 
     fromJSON(data: any, meta?: any): this | null {
+        if (data.camOptions || data.aspect === 'auto')
+            data = {...data}
         if (data.camOptions) {
-            // todo
-            console.error('todo: old file camOptions')
+            const op = data.camOptions
+            if (op.fov) data.fov = op.fov
+            if (op.focus) data.focus = op.focus
+            if (op.zoom) data.zoom = op.zoom
+            if (op.aspect) data.aspect = op.aspect
+            // todo: add support for this
+            // if (op.left) data.left = op.left
+            // if (op.right) data.right = op.right
+            // if (op.top) data.top = op.top
+            // if (op.bottom) data.bottom = op.bottom
+            // if (op.frustumSize) data.frustumSize = op.frustumSize
+            // if (op.controlsMode) data.controlsMode = op.controlsMode
+            // if (op.controlsEnabled) data.controlsEnabled = op.controlsEnabled
+            delete data.camOptions
         }
         if (data.aspect === 'auto') {
             data.aspect = this.aspect

src/plugins/postprocessing/TonemapPlugin.ts

             delete data.extension.enabled
             delete data.pass
         }
+        // legacy
         if (data.extension) {
-            console.error('TODO: old file')
-            return null
+            data = {...data, ...data.extension}
+            delete data.extension
+            if (data.clipBackground !== undefined) {
+                if (this._viewer) this._viewer.renderManager.screenPass.clipBackground = data.clipBackground
+                else console.warn('TonemapPlugin: no viewer attached, clipBackground ignored')
+                delete data.clipBackground
+            }
         }
         return super.fromJSON(data, meta)
     }