Hi , i need to make something very easy , but i cant find  a way.
I just need to make a program that each 5 seconds it calls a function that makes it rotate from one angle to another then the next time the function is called it rotate back to its orignial position.
So : Each 5 seconds it rotates from 0 to 60 angle and then the next time (after 5 seconds again) it rotates back to 0, after 5 secnds it rotates again from 0 to 60  and so on.....


My question should be how can i make a function that everytime it is called can make an interpolation from one point to another?
how can i do this?



in the following code each 5 seconds it add just one value, but i would like that instead of adding just one value, it can interpolate from 0 to 70


any idea?

1. 
   float rotate_variable = 0  ;
   
   void setup()
   {
     size(300, 300, P3D);
    
   }
   
   
   
   void draw()
   {
    
      float m = millis();
     background(250, 0 , 0);
      
    // float m = millis();
     if (m % 1000 == 0) {
     funcion_rota( );
    
   };
    
    //lerp
    
   translate(width/2, height/2);
   rotate(radians(rotate_variable));
   rect(-26, -26, 52, 52);
    
   }
   
   
   
   void funcion_rota() {
     rotate_variable = rotate_variable + 1;
   
   
   }