增加弹窗模态层透明度参数

src/zeroing/game-warpper/GameStage.ts

@@ -291,10 +291,14 @@ export class GameStage extends Node {
 		let pParent = blackLayer.parent;
 		if (hasView) {
 			target.addChildAt(blackLayer, target.childNum - 1 - (view ? 0 : 1));
+			let modalAlpha = 0.7;
+			if(options && options.hasOwnProperty('modalAlpha')){
+				modalAlpha = options.modalAlpha;
+			}
 			if (!pParent || blackLayer['tween_count'] > 0) {
 				blackLayer.alpha = 0;
 				Tween.get(blackLayer, null, null, true)
-					.to({alpha: 0.7}, 300);
+					.to({alpha: modalAlpha}, 300);
 			}
 		} else if (pParent) {
 			Tween.get(blackLayer, null, null, true)