panda3d创建一个避免点到底层按钮的遮罩

编写游戏的时候经常要用到弹出游戏内对话框窗口什么的
而在弹出窗口时要禁用底层窗口的元素怎么办呢……
于是大地想到了一个跟HTML类似的方法，在窗口和下面之间加一个全透明遮罩层
遮罩层用DirectButton就能解决会按到下面的按钮的问题了

但是新的问题来了，在下面加DirectButton的话因为PGButton的特性会阻断Panda3d的事件
所以滚轮什么的也不能在弹出窗口用了

那么……只要让这个遮罩层能够重新发送滚轮和其他鼠标事件就可以了！

于是

#-*- coding:utf-8 -*-
'''
====================================================================================

   Copyright 2013, 2014 Windy Darian (大地无敌), Studio "Sekai no Kagami" 
   (世界之镜制作组) of Seven Ocean Game Arts （七海游戏文化社
   , 北京航空航天大学学生七海游戏文化社） @ /404.html#sogarts.com/

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

====================================================================================
Created on Apr 6, 2013
dialog mask
@author: Windy Darian
'''

from panda3d.core import NodePath,PGButton,MouseButton
from direct.showbase.DirectObject import DirectObject
import direct.gui.DirectGuiGlobals as DGG
from direct.gui.DirectButton import DirectButton

class DialogMask(DirectButton):
    '''used to generate a full-screen mask to prevent button-clicking below the focused window/dialog
    Added some tricks to make panda3d mouse events still available
    '''
    B1PRESS = PGButton.getPressPrefix() + MouseButton.one().getName() + '-'  
    B2PRESS = PGButton.getPressPrefix() + MouseButton.two().getName() + '-'  
    B3PRESS = PGButton.getPressPrefix() + MouseButton.three().getName() + '-'
    B4PRESS = PGButton.getPressPrefix() + MouseButton.four().getName() + '-'
    B5PRESS = PGButton.getPressPrefix() + MouseButton.five().getName() + '-'
    WHEELUP = PGButton.getReleasePrefix() + MouseButton.wheelUp().getName() + '-'
    WHEELDOWN = PGButton.getReleasePrefix() + MouseButton.wheelDown().getName() + '-'
    WHEELLEFT = PGButton.getReleasePrefix() + MouseButton.wheelLeft().getName() + '-'
    WHEELRIGHT = PGButton.getReleasePrefix() + MouseButton.wheelRight().getName() + '-'
    B1RELEASE = PGButton.getReleasePrefix() + MouseButton.one().getName() + '-'  
    B2RELEASE = PGButton.getReleasePrefix() + MouseButton.two().getName() + '-'  
    B3RELEASE = PGButton.getReleasePrefix() + MouseButton.three().getName() + '-'
    B4RELEASE = PGButton.getReleasePrefix() + MouseButton.four().getName() + '-'
    B5RELEASE = PGButton.getReleasePrefix() + MouseButton.five().getName() + '-'
    
    def __init__(self):
        DirectButton.__init__(self,parent = aspect2d, frameColor =(1,1,1,0), relief = DGG.FLAT,commandButtons = [])
        self.accept('window-event', self.windowResize)
        self.windowResize(None)
        #trick: make this re-throw mouse events
        self.bind(self.B1PRESS, self.rethrowEvent,['mouse1'])
        self.bind(self.B2PRESS, self.rethrowEvent,['mouse2'])
        self.bind(self.B3PRESS, self.rethrowEvent,['mouse3'])
        self.bind(self.B4PRESS, self.rethrowEvent,['mouse4'])
        self.bind(self.B5PRESS, self.rethrowEvent,['mouse5'])
        
        self.bind(self.WHEELUP, self.rethrowEvent, ['wheel_up'])
        self.bind(self.WHEELDOWN, self.rethrowEvent, ['wheel_down'])
        self.bind(self.WHEELLEFT, self.rethrowEvent, ['wheel_left'])
        self.bind(self.WHEELRIGHT, self.rethrowEvent, ['wheel_right'])
        
        self.bind(self.B1RELEASE, self.rethrowEvent,['mouse1-up'])
        self.bind(self.B2RELEASE, self.rethrowEvent,['mouse2-up'])
        self.bind(self.B3RELEASE, self.rethrowEvent,['mouse3-up'])
        self.bind(self.B4RELEASE, self.rethrowEvent,['mouse4-up'])
        self.bind(self.B5RELEASE, self.rethrowEvent,['mouse5-up'])
        
    def windowResize(self,arg):
        #Make this mask fill the screen
        self.reparentTo(aspect2d,sort = self.getSort())
        aspect = base.getAspectRatio()
        if aspect > 1:
            self['frameSize'] = (-aspect,aspect,-1,1)
        elif aspect: 
            hh = 1.0/aspect
            self['frameSize'] = (-1,1,-hh,hh)
            
    def setCommandButtons(self, *args, **kwargs):
        #inherited 
        pass
        
    def rethrowEvent(self,sevent,event):
        messenger.send(sevent)
        
                
    def destroy(self):
        self.ignoreAll()

在自定义窗体中，只要使用这个DialogMask类，在自定义窗体或对话框显示出时执行mask.show()，消失是执行mask.hide()就可以了

[caption id="attachment_469" align="alignnone" width="625"]
鼠标能正常点到前面的按钮，但点不到底层的按钮，鼠标滚轮滚动的事件也正常[/caption]