增加自定义模块支持

package.json

@@ -27,7 +27,7 @@
   "scripts": {
     "build-webpack": "webpack",
     "rollup": "rollup -c",
-    "rename": "node scripts/rename-hash.js dist/index.js",
+    "rename": "node scripts/rename-hash.js dist/engine.js",
     "build": "yarn rollup && yarn rename",
     "ts": "dts-bundle --name engine --main types/src/index.d.ts --out ../../dist/index.d.ts",
     "test": "echo \"Error: no test specified\" && exit 1",

rollup.config.js

@@ -12,7 +12,7 @@ export default {
 	input: 'src/index.ts',
 	output: [
 		{
-			file: `dist/index.js`,
+			file: `dist/engine.js`,
 			format: 'umd',
 			name: 'engine',
 			sourcemap: true,

src/zeroing/game-warpper/GameStage.ts

@@ -92,17 +92,21 @@ export class GameStage extends Container {
 		let total = assets.length;
 		if (customs) {
 			for (let custom of customs) {
+				if(custom.assets){
 					total += custom.assets.length;
 				}
 			}
+		}
 
 		showLoadingView();
 		await loadAssets(assets, p);
 		if (customs) {
 			for (let custom of customs) {
+				if(custom.assets){
 					await loadAssets(custom.assets, p);
 				}
 			}
+		}
 		hideLoadingView();
 
 		this.start();