Need advice on how to detect two keys being up at once.

Scripting Issues
1

I asked on the panda3d irc channel earlier about this but couldnt get it to work so i thought id finally ask here.

My problem is i have a ship that when you press a it strafes right and left when you press b but i need it to return to the center when both keys are up.

i have a task called playerMove and i put this in it:

        base.accept('a-repeat', ship.playerStrafe, extraArgs = [self, "left"] )
        base.accept('d-repeat', ship.playerStrafe, extraArgs = [self, "right"] )
        base.accept('a-up', ship.playerStrafe, extraArgs = [self, "center"])
        base.accept('d-up', ship.playerStrafe, extraArgs = [self, "center"])

but when i try to detect when the a and d key are up it can only detect one of them at a time. i need them to both be detected in one frame.
Here is my playerStrafe code if you need it :

   def playerStrafe(self, dir):
        
        if self.strafeAmount != 0:
            self.ship.hide()
            self.copyShip.show()
        else:
            self.ship.show()
            self.copyShip.hide()
        
        if dir == "left":
            self.strafeCenter = 2
            if self.strafeAmount > -45:
                self.copyShip.setR(self.ship, -5)
                self.strafeAmount -= 5
            
            if self.strafeAmount == -45:    
                self.ship.setX(self.ship, -5)
            

            
        if dir == "right":
            self.strafeCenter = 2
            if self.strafeAmount < 45:
                self.copyShip.setR(self.ship, 5)
                self.strafeAmount += 5
            
            if self.strafeAmount == 45:           
                self.ship.setX(self.ship, 5)
        
        if dir == "center":
            if self.strafeCenter > 0:
                self.strafeCenter -= 1
           
            
            if self.strafeCenter == 0:

                if self.strafeAmount < 0:
                    self.copyShip.setR(self.copyShip, 1)
                    self.strafeAmount += 1
                    
                
                if self.strafeAmount > 0:
                    self.copyShip.setR(self.copyShip, -1) 
                    self.strafeAmount -= 1

the strafe center is set to 2 whenever the player presses a or d but its supposed to go back to 0 when the keys are up (decreased by 1 when each key is up)

Its kinda confusing, i know. But if you have any advice i would really appreciate it!

2

I haven’t executed this code, but this is the general idea:


class blah():


    self.accept('a',self.strafeLeft)
    self.accept('d',self.strafeRight)
    self.accept('a-up',self.noStrafeLeft)
    self.accept('d-up',self.noStrafeRight)


    taskMgr.add (self.strafeTask,'strafeTask')



    def strafeLeft(self):
        self.strafingLeft = 1


    def strafeRight(self):
        self.strafingRight = 1


    def noStrafeLeft(self):
        self.strafingLeft = 0


    def noStrafeRight(self):
        self.strafingRight = 0



    def strafeTask(self,task):
        if self.strafingLeft == 1:
            pass  #Strafing to the left code here

        if self.strafingRight == 1:
            pass  # strafing to the right code here

        if (self.strafingLeft == 0) and (self.strafingRight == 0):
            pass  #Not strafing, both keys are up!

        return task.cont

Hope this helps!

3

You’d want to use Keyboard Polling instead of events for this. From this topic you can copy this function by ynjh_jo:

  def getButton(key):
    if len(key)==1:
       kb=KeyboardButton.asciiKey(key)
    else:
       if key=='del': key='_del'
       if hasattr(KeyboardButton,key): # keyboard button
          kb=getattr(KeyboardButton,key)()
       else:                           # mouse button
          kb=getattr(MouseButton,key)()
    return base.mouseWatcherNode.isButtonDown(kb)

So to use this, fill out the following psuedo code and place it inside your task

    ...
    if getButton('a'):
       strafeLeft
    if getButton('d'):
       strafeRight
    if not getButton('a') and not getButton('d'):
       center
    ...