Hello World!
I'm going to make a fish swim back and forth
a random amount.
I have a clown fish and I'd like the clown fish to swim
back and forth
in this area, but I want him sometimes
to go a little bit then turn around and go back and
and not always go exactly
to this point and this point.
So I'm going to make this point
and add an object marker,
and just call this onTheLeft
and then I'm going to move him
over to the other side, and
add an object marker there and call it onRight.
So let's go to our code.
I'm going to get rid of that Java code on the side.
We have lots of room to see our
scene,  so we started here
and I'm going to have them going back and forth so let's do that:
while forever,  while(true)
and he's over here so the first thing
the clown fish needs to do,
is turn to face the onLeft position
and then he is going to move
Initially I'm just going to have him move
That whole amount so he is going to move forward
Just make it 2 for now,
and then he's going to turn to face
onTheRight
and then he's going to move again,
then, again, forward,
I'll make that 3.
Let's run this.
and it isn't really quite enough,
but he's doing the same thing over and over and over again.
and I would like to look a little bit more random.
So I'm going to use a variable
and it will be a double and I'm going to call it distance.
We have to give it some initial value.
I want to make the distance a random amount
the distance from the fish to that marker.
(Let's make this a little smaller so you can see what I'm doing here.
really small, OK.)  So it's going to be a random amount
from something to something
and the first value I'm going to make .25
and the second value .5
but instead of the .5 I'm going to use the function.
in the function I want to use
is to get the distance to,
that's going to replace that second value.
the onLeft,
and then he's going to move that distance.
and then I'm going to do the same thing,  let's just run that.
He turns around and he moves some distance.
but going back we've still got that fixed amount.
So let's fix that now.
I need to assign a new value to distance
and distance is equal to .25
but then I want that to be a random amount
between .25 and
We'll just put in 0.25 for the first value and 1 for the second value.
and then I'm going to use the function here that distance,
get distance to this.onLeft.
Ok, this second one is going to be this.onRight.
Let's run this and see how were doing here.
One of the things I wanted to see here is that it looks random.
Now hear something interesting, you'll notice
that the duration is the same for all of those.
So if he's going a short distance he goes very slowly.
And if he's going along distance he goes a little faster.
So one of things we could do would be to make the duration
have some relationship to
the distance that he's traveling,
so that he appears to swim
at the same speed, but I'm going to leave that
as an experiment for you.
So let's just review what we've done here.
I'm going to do while true that means it
just keeps repeating over and over.
I have distance which is a
random value between .25
and the distance to the onLeft marker.
and he's going to turn to face the onLeft marker
and move towards it that distance.
Then he's going to turn to face the onRight marker,
and then we calculate the distance
between .25 and the distance
between the clown fish and the marker on the right.
and then he'll move forward,
We have to change that to distance,
Change that to distance.
So let's run that again and see how that looks.
Notice that disparity
in the speed depending on how far he has to go.
So we could make the duration
a random number or make a factor of
the distance that he's going,
and you should experiment with that all you want.