Why doesn't P3D work for me ?

TheSpectron3

Hey, I recently tried to work with P3D and OpenGL on Processing, but for some reason it doesn't let me put the P3D argument in the size function, and says "Declaration must include a precision qualifier or the default precision must have been previously declared", any idea of what's going on ?

this is my (very simple) code that i'm trying to run :

void setup(){
  size(400, 400, P3D);
  background(0);
}

void draw(){
  stroke(255);
  noFill();
  translate(-100, 20, 30);
  box(50);
}

Thanks !