From a3e16d37797bc05d89e88c6810d4c7bca3f58b48 Mon Sep 17 00:00:00 2001
From: Forrest Sun <the.forrest.sun@gmail.com>
Date: Sun, 9 Jun 2024 19:03:43 -0700
Subject: [PATCH] use Object3D's toJson on Particle System

---
 src/ParticleEmitter.ts       | 83 +++---------------------------------
 test/ParticleEmitter.test.ts | 19 ++++++++-
 2 files changed, 24 insertions(+), 78 deletions(-)

diff --git a/src/ParticleEmitter.ts b/src/ParticleEmitter.ts
index 1b55c0a..1b343f1 100644
--- a/src/ParticleEmitter.ts
+++ b/src/ParticleEmitter.ts
@@ -46,82 +46,11 @@ export class ParticleEmitter<E extends Object3DEventMap = Object3DEventMap> exte
     }
 
     toJSON(meta?: MetaData, options: SerializationOptions = {}): any {
-        // meta is a string when called from JSON.stringify
-        const isRootObject = meta === undefined || typeof meta === 'string';
-        const output: any = {};
-        // meta is a hash used to collect geometries, materials.
-        // not providing it implies that this is the root object
-        // being serialized.
-        if (isRootObject) {
-            // initialize meta obj
-            meta = {
-                geometries: {},
-                materials: {},
-                textures: {},
-                images: {},
-                shapes: {},
-                skeletons: {},
-                animations: {},
-                nodes: {},
-            };
-
-            output.metadata = {
-                version: 4.5,
-                type: 'Object',
-                generator: 'Object3D.toJSON',
-            };
-        }
-
-        // standard Object3D serialization
-        const object: any = {};
-
-        object.uuid = this.uuid;
-        object.type = this.type;
-
-        if (this.name !== '') object.name = this.name;
-        if (this.castShadow === true) object.castShadow = true;
-        if (this.receiveShadow === true) object.receiveShadow = true;
-        if (this.visible === false) object.visible = false;
-        if (this.frustumCulled === false) object.frustumCulled = false;
-        if (this.renderOrder !== 0) object.renderOrder = this.renderOrder;
-        if (JSON.stringify(this.userData) !== '{}') object.userData = this.userData;
-
-        object.layers = this.layers.mask;
-        object.matrix = this.matrix.toArray();
-
-        if (this.matrixAutoUpdate === false) object.matrixAutoUpdate = false;
-
-        // object specific properties
-
-        // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-        if (this.system !== null) object.ps = this.system.toJSON(meta!, options);
-
-        if (this.children.length > 0) {
-            object.children = [];
-            for (let i = 0; i < this.children.length; i++) {
-                if (this.children[i].type !== 'ParticleSystemPreview') {
-                    object.children.push(this.children[i].toJSON(meta).object);
-                }
-            }
-        }
-
-        if (isRootObject) {
-            // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-            const geometries = this.extractFromCache(meta!.geometries);
-            // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-            const materials = this.extractFromCache(meta!.materials);
-            // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-            const textures = this.extractFromCache(meta!.textures);
-            // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-            const images = this.extractFromCache(meta!.images);
-
-            if (geometries.length > 0) output.geometries = geometries;
-            if (materials.length > 0) output.materials = materials;
-            if (textures.length > 0) output.textures = textures;
-            if (images.length > 0) output.images = images;
-        }
-
-        output.object = object;
-        return output;
+        const children = this.children;
+        this.children = this.children.filter((child) => child.type !== 'ParticleSystemPreview');
+        const data = super.toJSON(meta);
+        this.children = children;
+        if (this.system !== null) data.object.ps = this.system.toJSON(meta!, options);
+        return data;
     }
 }
diff --git a/test/ParticleEmitter.test.ts b/test/ParticleEmitter.test.ts
index 95ff7fc..06722e3 100644
--- a/test/ParticleEmitter.test.ts
+++ b/test/ParticleEmitter.test.ts
@@ -15,7 +15,7 @@ import {
     SphereEmitter,
     TrailSettings,
 } from '../src';
-import {Layers, MeshBasicMaterial, NormalBlending, Texture, Vector3, Vector4} from 'three';
+import {Layers, MeshBasicMaterial, NormalBlending, Object3D, Texture, Vector3, Vector4} from 'three';
 import {QuarksLoader} from '../src';
 import {BatchedRenderer} from '../src';
 
@@ -124,4 +124,21 @@ describe('ParticleEmitter', () => {
         expect((system.rendererEmitterSettings as TrailSettings).startLength!.type).toBe('value');
         expect(system.behaviors.length).toBe(2);
     });
+
+    test('.fromJSON parent', () => {
+        // const meta = { geometries: {}, materials: {}, textures: {}, images: {} };
+        const parent = new Object3D();
+        parent.add(glowBeam.emitter);
+        const json = parent.toJSON();
+        // console.log(json);
+        const loader = new QuarksLoader();
+        const emitter = loader.parse(json, () => {}).children[0] as ParticleEmitter;
+        const system = emitter.system as ParticleSystem;
+        expect(system.rendererSettings.layers.mask).toBe(3);
+        expect(system.startTileIndex.type).toBe('value');
+        expect(system.rendererSettings.instancingGeometry).toBeDefined();
+        // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+        expect((system.rendererEmitterSettings as TrailSettings).startLength!.type).toBe('value');
+        expect(system.behaviors.length).toBe(2);
+    });
 });