At the moment I'm working on using the dist() function for a game I have, and this is a bit of side code I'm working on to figure this out. Presently it is not working properly. I want a red square to appear when the mouse controlled line gets within a certain range...... but I don't know how to give the distance function a range.

Is there a way to program in something like if (pos1 <=20 to pos2) then perform action?

Code is below. Changing <= will cause the square to always appear. Changing it to == and it will not appear even when I try to make them equal in program.

1. int startX;
   int startY;
   float endX;
   int endY;
   
   float posX; //mouse X position of player
   int posY; //mouse Y position of player
   int fireX;
   int fireY;
   
   
   void setup() {
     size(700,500);
     startX = 100;
     startY = 200;
     endX = 450;
     endY = 450;
   }
   
   void draw() {
     background(255);
     smooth();
     strokeWeight(2.5);
     stroke(255,0,0);
     line(startX, startY, endX, endY);
     float antidist = dist(fireX, fireY, posX, posY);
     float misdist = dist(startX, startY, endX, endY);
     if (antidist <= misdist) {
       fill(255,0,0);
       rect(50,100,100,50);
     } else{
     }
    
     }
   
   
   void mousePressed() {
     fireX = 250;
     fireY = 480;
     posX = mouseX;
     posY = mouseY;
    
    
     smooth();
     strokeWeight(3);
     stroke(255,0,0);
     line(fireX, fireY, posX, posY);
   }