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COLTON OGDEN: All right.

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Pong 5 was a bit more work.

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We ended up actually
refactoring our code base

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to use object-oriented
programming or a little taste

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there of, a little bit different
than having a bunch of variables

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keeping track, a little more
procedural style as before,

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much like how C actually is written.

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But the way we structure things now
is more akin to what you might see

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in Java, or what you might
see in C#, or even in Python,

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depending on what code
base you're working on--

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a little bit easier to keep track
of multiple things moving around.

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And games in particular are very sort
of prone to this model of programming.

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Now this is a little bit of a break.

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It's a little bit of a simpler
iteration in the Pong track.

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We're going to be taking a look
just at implementing a simple FPS

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marker at the top left of the screen.

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And to do that, you can see there
it's written in green text, usually

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the same font, same size as the
text at the top of the screen.

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But this is literally just going
to use a simple function built

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into love that just tells us what
our frame rate is currently at.

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And so here are a
couple of the functions

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in particular that we're going to
look at, so love.window.setTitle.

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So this one is not germane to
what we've just talked about,

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but if you've noticed, so far at
the very top we've had untitled.

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But now, as is shown in
this particular example,

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we have the word "Pong"
actually written there.

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So this is a little bit of a
cleanup, just something that

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looks better if you're running
your game in a windowed setting.

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So we're going to be doing that.

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It literally just sets the title to
a string, whatever you want it to be.

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More germane to what we've talked
about is love.timer.getFPS,

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which is just going to return as a
float the FPS value of our game--

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so very simple, very straightforward.

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And that's pretty much it.

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So let's actually go
right into the code here.

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So what I'm going to do is I'm going
to scroll down to the very bottom.

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And what we're going to do is
just render this to the screen.

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So we know we want a string
rendered at the top left.

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All I'm going to do really is I just
need to insert something right here.

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Basically after everything else is
rendered, I want to display the FPS.

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Now I don't want to get into the
habit of just writing a bunch of code

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in place inside these methods.

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I think this would be
more suited to a function.

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So let's say I want to
display FPS like that.

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I'm calling it, like you might have
seen in C, just a very simple, sort

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of procedural function call.

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Because what I'm going to do is just
write it here in main.lua itself.

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So I'm going to say function displayFPS.

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I'm not even going to
have it take a parameter.

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This is going to be
very straightforward.

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I'm going to say love.graphics.setColor.

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And this, actually, I don't think
we've taken a look at either.

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We've taken a look at
love.graphics.clear.

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Love.graphics.setColor
is very similar to that,

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only this actually toggles
the color for things

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like drawing text to the screen,
which by default, everything,

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as you've noticed, is white.

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So we're going to say
love.graphics.setColor.

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I want this to be green,
so, again, it's RGB alpha.

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So the G component is
what we care about.

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So I'm going to say 0 for the red.

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Let's say 255-- well, rather--

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we'll skip the 255 stuff.

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We'll just say 0,1 for full green,
0 for the blue, and 1 for the alpha.

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Then I'm going to say
love.graphics.setFont

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of smallfont and love.graphics.print.

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And then we'll say our
FPS is going to be--

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well, we need to get the FPS.

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So in order to do that, I'm going
to say tostring love.timer.getFPS

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as a function call.

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And we need this tostring
method-- this is very important--

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because this is going to actually
give us an integer value.

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And this value is going to be
incompatible with adding to a string.

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You might actually notice that
we have this dot dot here.

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This dot dot is the string
concatenation operator.

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So this just means we add
two strings together, one

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and then tail it at the
end of the other one.

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You probably touched on this
in C throughout the course.

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Now it's a different operator in Lua.

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In Python, it's a plus.

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And in C-- well, you can't
really do that with C. You

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have to use something else altogether.

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But what we're going to do is
say FPS, concatenate with that.

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And then we're going to-- let's
just draw this, let's say, at 40.

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And for-- actually, no.

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We'll do it at, yeah, 40 and 20.

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And that's it.

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And then one last thing
I do want to do actually

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is set everything back
to white as the default

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color for whenever it draws
the next thing-- the paddles,

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and the text, and whatnot.

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So I'm going to say 1, 1,
1, 1 at the end of that.

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And if we run the code
here, we do indeed

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see we have an FPS display
at the top of the screen.

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And it started off at 49.

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It's a little bit of a weird thing.

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Love actually has to get
a little bit of frame data

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so that it can calculate what
the FPS is, because it actually

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tracks it across multiple frames.

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That's why at first it was 0, then
49, and now it is smoothly at 60.

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Thankfully, my computer is strong
enough to run this very simple, barely

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functioning Pong example.

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So that was it for Pong 6, very simple.

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In the next update, we're going to
take something a little bit meatier

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on our hands, the collision update.

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So so far, the ball does not actually
collide with the paddle at all.

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It just will go straight
through because we

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have no code to test for whether the
ball and the paddle have intersected.

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So we're going to add this major change
to the code base in the next section

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and start talking about
collision with Pong 7.

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