I have to draw a triangle with mouse clicks (3 clicks = 1 triangle). I have this code:

1. void setup()
   {
     size(600, 480);
     background(255); 
    
     beginShape(TRIANGLES);
   }
   
   void draw()
   {
   }
   
   void mousePressed()
   {
       point(mouseX, mouseY);
       vertex(mouseX, mouseY);
   }

It don't draw any point and any triangle. What's wrong?

Thanks!