I'm having trouble getting my code to wait for some form of user input, either a mouse click or key press. I've seen others using noLoop() and loop(), though these appear to complete the code in draw() before pausing. I want my code to pause in one spot until the user inputs something. I've tried setting up while loops with a condition which should be met if the user presses the mouse but this seems to get into an infinite loop, as though the mousePress is never true (see code below).

If anyone has any thoughts on how to do this, I would be very thankful.

Code:

boolean cont = false;

void setup(){
    size(256, 256);  // Stage size
}

void draw(){
    println("start");
    while(cont == false){
      delay(100);
      if(mousePressed){
        cont=true;
      }
    }
   println("done");
}     

jayL wrote on Jan 25^th, 2010, 3:48pm:


That's a bad approach for many reasons.  The main one is the while loop - you need to be very careful when you use these otherwise you can easily get into an infinite loop and crash your sketch.  You also appear to be 'fighting the draw loop': "I want my code to pause in one spot".

The problem is that if you 'pause' the code, using while loops, noLoop() etc. it's no longer registering input: input events are processed after the draw loop completes.  draw loop paused - no input registered.  That's why your mousePressed isn't registered.

In actual fact as well as using the methods suggested by TfGuy44 you were almost there.  Rather than 'pausing' you need to think more along the lines of 'skipping over' anything you don't want to happen yet:

Code:

boolean cont = false;

void setup(){
    size(256, 256);  // Stage size
}

void draw(){
    // use a condition not a loop
    if(cont == true){
      // I don't want this to happen yet
      println("mouse was pressed");
    }

    if(mousePressed){
        cont=true;
    }

}

// the separate methods approach has some advantages
// e.g. separates user input from draw = potentially greater 
// clarity of code; and also handles more events
void mouseReleased() {
  cont = false; 
}