How to repeat code?

Processing.py
1

Hi! I’m having trouble with a simple project.
:arrow_right: The aim is to move an image to a designated box. Once the image is in the box, it snaps into place. By clicking a reset button, the image will return to its starting spot and is able to be dragged + snapped into the destination again.

Below is my code. Apologies if it’s confusing, I’ve tried my best to include explanations.

My code:

overBox = False 
locked = False
xOffset = 0.0
yOffset = 0.0
entered = False
reset = False 

def setup():
    size(640, 360)
    global bx, by, box1
    bx = width / 2
    by = height / 2
    box1 = loadImage("drag.png")

def draw():
    global bx, by, overBox
    background(0)
    
    rect(20, 20, 200, 200) #the destination
    image(box1, bx, by) #the box to be dragged to the destination
    rect(400, 20, 100, 100) #the reset button
    
    if bx < mouseX < bx + 100 and by < mouseY < by + 100: #if mouse is over the box
        overBox = True
        if not locked:
            pass
    else:
        overBox = False
    
    if entered: #if the the box is inside the destination, snap it in place
        bx = 40
        by = 40
    
    if reset: #if the refresh button is clicked, reset the box to its original place
        bx = width / 2
        by = height / 2

def mousePressed():
    global locked, xOffset, yOffset, reset
    if overBox:
        locked = True
    else:
        locked = False
    xOffset = mouseX - bx
    yOffset = mouseY - by
    if mouseX > 400 and mouseX < 500 and mouseY > 20 and mouseY < 120: #mouse presses the reset button
        reset = True

def mouseDragged():
    global bx, by
    if locked:
        bx = mouseX - xOffset
        by = mouseY - yOffset

def mouseReleased():
    global locked, entered
    locked = False
    if bx + 100 < 220 and by + 100 < 220: #if the box is released in the destination
        entered = True

Right now, the code manages to return the box to its starting spot but my attempts to repeat the dragging+snapping code have failed.

I have tried doing something like this:

#setup stuff

def draw():
    background(0)
    resetFunction()

def resetFunction():
    global bx, by, overBox
    #code to make box drag and snap  
    if reset: 
        bx = width / 2
        by = height / 2
        resetFunction()

But I get a NullPointerException error message. I’ve also tried using a while loop but it also didn’t work.

Thank you in advance!

2

Hi @snakey, I think you need a state machine. Lots of info, go Googling. In simple terms declare a global integer, the value in it states what phase the game is, e.g. 0 = nothing, 1 = dragging, 2 = close to target and auto-moving in, 3 = on target and finished. The action, in draw or functions called by draw, chooses what to do depending on state. Depending on conditions the action can change the state.

2 Likes
3

To any people who might have the same problem, I moved my variables to the setup function, and called the function from mousePressed!

Example:

def setup():
     overBox = False 
     locked = False
     #etc...

def mousePressed()
     if mouseX > 100 and mouseX < 200 #etc...
     setup()
1 Like