WEBVTT 00:00.150 --> 00:06.960 Hello again! In this video, we are going to add the paddle to our game. The paddle is this thing. Or you 00:06.960 --> 00:10.830 could call it a bat, perhaps. This sits at the bottom of the screen. 00:11.310 --> 00:12.290 It moves to the left 00:12.390 --> 00:18.630 and the right, when the user presses one of the keys. And if the ball hits it, it changes the action. So 00:18.630 --> 00:22.500 we can move this paddle around, and use it to change the direction of the ball. 00:23.880 --> 00:29.010 The code to make the paddle appear on the screen is very similar to the code that we initially write for 00:29.010 --> 00:30.990 making the ball appear on the screen. 00:33.320 --> 00:37.400 The only potentially tricky part is getting the coordinates correct. 00:38.150 --> 00:40.820 So we want the paddle to appear at the bottom of the screen. 00:41.420 --> 00:45.350 So y equals zero at the top and y equals window height at the bottom. 00:46.310 --> 00:51.020 The Sprite constructor takes the coordinates of the origin of the bounding rectangle. 00:51.620 --> 00:57.290 So if we use y equals window height, then the top left hand corner of the paddle will be on the bottom 00:57.290 --> 01:02.570 of the window. And the rest of the paddle will be below the bottom of the window, so it will not be visible. 01:04.130 --> 01:05.950 So we need to correct for that. 01:06.020 --> 01:11.720 So we need to subtract the height of the paddle from the height of the window, and that will put the 01:11.720 --> 01:14.150 origin of this window in the correct place. 01:15.290 --> 01:17.360 So you may want to have a go at doing this yourself. 01:17.750 --> 01:21.710 The code is very similar to the code that we had originally for making the ball appear on the screen. 01:22.130 --> 01:27.020 Do not worry about making the paddle move, or interact with the ball or the keyboard, just yet. 01:27.350 --> 01:28.250 We will do that later on. 01:28.970 --> 01:32.960 So I will give you an opportunity to pause the video and try that for yourselves. 01:35.400 --> 01:36.930 So here is my solution. 01:37.380 --> 01:44.160 I have added two more constants, for the height and the width of the paddle. A paddle class which inherits 01:44.160 --> 01:48.420 from moving_entity. And it is very, very similar to the ball class. 01:50.580 --> 01:56.970 Obviously we load up the paddle image, and not the ball image. And also, we set the initial velocity 01:56.970 --> 02:01.680 to be zero, because the paddle does not move unless the user presses one of the keys. 02:03.560 --> 02:05.180 And for update(), 02:05.180 --> 02:09.590 we are not doing anything special, just yet. And draw() is the same again. 02:11.870 --> 02:15.230 In the main source code, we #include "paddle.h". 02:15.230 --> 02:18.470 We create an object of the paddle. 02:19.010 --> 02:26.120 The x coordinate is half the width of the window, and the y coordinate is the window height minus the paddle 02:26.120 --> 02:26.450 height, 02:26.870 --> 02:28.550 as I explained in the slide. 02:30.530 --> 02:32.510 Then we do all the usual things. 02:37.050 --> 02:40.230 And when we update the graphics, we update the paddle as well. 02:40.590 --> 02:44.790 And for displaying the graphics, we need to draw the paddle before we display the window. 02:47.470 --> 02:48.100 So there it is. 02:48.160 --> 02:49.030 We have our paddle. 02:49.720 --> 02:52.380 And so as you can see, it does not interact with the ball just yet. 02:52.390 --> 02:56.260 And if I press the arrow keys, then nothing happens. 02:56.500 --> 02:57.550 But we can add that later on. 02:58.210 --> 02:59.490 Okay, so that is it for this feature. 02:59.890 --> 03:00.700 I will see you next time. 03:00.700 --> 03:01.630 But until then, 03:02.600 --> 03:03.200 keep coding!