1 00:00:08,970 --> 00:00:12,800 We've reached the last lecture in module 11, so as 2 00:00:12,800 --> 00:00:16,689 a final reminder, here are the module 11 learning objectives. 3 00:00:19,890 --> 00:00:23,300 So, last time we finished implementing our rubber chicken class. 4 00:00:23,300 --> 00:00:26,930 And it's time to actually put that class into a game. 5 00:00:26,930 --> 00:00:29,590 And so, we're now going to build a complete game that 6 00:00:29,590 --> 00:00:33,190 includes the rubber chicken as one of the classes in the game. 7 00:00:33,190 --> 00:00:37,470 I've already written all the code, but I've also commented all out 8 00:00:37,470 --> 00:00:43,010 again, and captured the sequence that I followed to develop the code. 9 00:00:43,010 --> 00:00:45,130 So I'm going to bring you through the process from start 10 00:00:45,130 --> 00:00:48,170 to finish, and I won't actually be typing code, 11 00:00:48,170 --> 00:00:51,540 I'll just be uncommenting pieces I already typed in. 12 00:00:51,540 --> 00:00:55,920 And talking about sort of interesting things as we get to those pieces. 13 00:00:55,920 --> 00:00:59,050 So let's go right to the IDE, I've already got 14 00:00:59,050 --> 00:01:01,810 it opened up, and zoomed, thank goodness for both of those. 15 00:01:05,350 --> 00:01:10,250 So the initial stuff, and I'm going to try not to get dizzy, I'm going to pop back 16 00:01:10,250 --> 00:01:16,610 and forth between the Power Point, and the code so that we can look at each step. 17 00:01:16,610 --> 00:01:19,510 But before we start doing that, I want to show you 18 00:01:19,510 --> 00:01:23,100 the core things that I've already included in the game. 19 00:01:23,100 --> 00:01:27,080 So we already have the standard constants for window width and window height, I 20 00:01:27,080 --> 00:01:30,750 have some information about chickens, how many chickens should be in the game, and 21 00:01:30,750 --> 00:01:32,900 how much damage each chicken inflicts. 22 00:01:33,920 --> 00:01:36,120 I'm saving the three sprites that we're using 23 00:01:36,120 --> 00:01:38,780 in the game for efficiency in this texture 24 00:01:38,780 --> 00:01:40,880 2Ds, because we're going to be creating bears 25 00:01:40,880 --> 00:01:43,260 and chickens and explosions all over the place. 26 00:01:43,260 --> 00:01:45,990 So just loading this content once and then saving it 27 00:01:45,990 --> 00:01:47,750 and using it as we need it is a good idea. 28 00:01:48,850 --> 00:01:50,270 We have some game entities. 29 00:01:50,270 --> 00:01:54,600 We have a list of rubber chickens, a list of bears, and a list of explosions. 30 00:01:54,600 --> 00:01:56,650 And you will notice that 31 00:01:56,650 --> 00:02:01,750 in this constructor, for the list of rubber chickens, I've actually provided an 32 00:02:01,750 --> 00:02:07,150 argument, whereas, all the lists we've created so far I haven't done that. 33 00:02:07,150 --> 00:02:12,004 This just tells the system how large that list should be. 34 00:02:12,004 --> 00:02:16,316 So it's the capacity of the list, and I actually know I will always 35 00:02:16,316 --> 00:02:21,937 have exactly num chickens, chickens so if I provide the capacity first, then I don't 36 00:02:21,937 --> 00:02:24,350 have to grow the list dynamically. 37 00:02:25,650 --> 00:02:28,220 We have teddy bear spawn support, I have speed 38 00:02:28,220 --> 00:02:31,020 for the teddy bears, they'll spawn every two seconds. 39 00:02:31,020 --> 00:02:34,010 We've seen this timer stuff before, and I will need a random number 40 00:02:34,010 --> 00:02:38,970 generator to generate the random x location for teddy bears that I spawn. 41 00:02:40,620 --> 00:02:42,880 I've set the resolution and made the mouse visible 42 00:02:42,880 --> 00:02:45,160 because we click on rubber chickens to launch them. 43 00:02:45,160 --> 00:02:47,170 And we want to make sure the player 44 00:02:47,170 --> 00:02:52,920 can see where the mouse is to do that. In the load content I haven't done 45 00:02:52,920 --> 00:02:58,080 too much exciting here, I've loaded these three sprites, so you've seen that before. 46 00:02:58,080 --> 00:03:03,120 But I'm also calling this spawn initial rubber chickens method. 47 00:03:03,120 --> 00:03:07,620 That doesn't come free in the game one class, I wrote this, so let's 48 00:03:07,620 --> 00:03:12,550 go to the definition, I right-clicked and about halfway down, so this is just 49 00:03:12,550 --> 00:03:18,310 writing a method like the methods we've already written to roll the die. 50 00:03:18,310 --> 00:03:20,660 To tell the rubber chicken to draw and update 51 00:03:20,660 --> 00:03:25,500 themselves, this is just another method that I've written. 52 00:03:25,500 --> 00:03:26,890 Now, it turns out that this one 53 00:03:26,890 --> 00:03:30,180 is slightly different, because I've made it private. 54 00:03:30,180 --> 00:03:33,720 Nobody outside this class should ever be able to spawn 55 00:03:33,720 --> 00:03:38,520 the initial rubber chickens and so I made that private. 56 00:03:38,520 --> 00:03:41,868 And it can only be used from within the game one 57 00:03:41,868 --> 00:03:47,040 class, and specifically, it's only used from the load content method. 58 00:03:47,040 --> 00:03:50,320 So I'm actually going to do some math here, 59 00:03:50,320 --> 00:03:53,590 where I figure out what the spacing between the 60 00:03:53,590 --> 00:03:56,160 rubber chickens should be based on the window width 61 00:03:56,160 --> 00:03:59,050 and how many rubber chickens I'm going to have. 62 00:03:59,050 --> 00:04:03,290 And I then set the current x, 63 00:04:03,290 --> 00:04:07,960 so this is the x for the rubber chicken I am about to create to x spacing over 2. 64 00:04:07,960 --> 00:04:10,510 So this is going to be way over near the left side of 65 00:04:10,510 --> 00:04:13,400 the window though not all the way up against left side of the window. 66 00:04:14,590 --> 00:04:16,560 I then spawn the chickens. 67 00:04:16,560 --> 00:04:20,180 I'll talk about this get chicken start y method right now. 68 00:04:20,180 --> 00:04:21,900 Again, another private method. 69 00:04:23,070 --> 00:04:25,210 And really, it just returns window height, 70 00:04:25,210 --> 00:04:28,100 so the very bottom, minus chicken.height over two. 71 00:04:28,100 --> 00:04:29,690 So this is going to put the chicken 72 00:04:29,690 --> 00:04:33,230 standing on the bottom of the window, basically. 73 00:04:33,230 --> 00:04:37,520 I wrote this method because I discovered that numerous 74 00:04:37,520 --> 00:04:41,000 times I needed to do this exact same calculation. 75 00:04:41,000 --> 00:04:44,280 So instead of doing the calculation at three different places 76 00:04:44,280 --> 00:04:47,650 in my code, I did it in this one place instead. 77 00:04:47,650 --> 00:04:51,600 So, I get the chicken start Y, and now I do a FOR loop. 78 00:04:51,600 --> 00:04:53,170 This is much like the FOR loop when 79 00:04:53,170 --> 00:04:58,060 we had the initial num teddies a long time ago when we were learning about FOR loops. 80 00:04:58,060 --> 00:05:00,610 And so I go through the FOR loop, I add a new 81 00:05:00,610 --> 00:05:07,340 rubber chicken, with a sprite, a location and how much damage it inflicts. 82 00:05:07,340 --> 00:05:12,980 And then, I change the current x by adding x spacing to it, so that the next 83 00:05:12,980 --> 00:05:18,310 time around the loop, when I'm on chicken number one, our second chicken, it will 84 00:05:18,310 --> 00:05:21,530 be at x spacing plus x spacing over 2. 85 00:05:21,530 --> 00:05:25,583 So I'm, you know, putting them in a row across the bottom of the screen. 86 00:05:25,583 --> 00:05:31,694 And I do that with that for loop and now if we go back to the Power Point slide, 87 00:05:31,694 --> 00:05:37,518 we see that I have done this step, I've spawned the initial chickens. 88 00:05:37,518 --> 00:05:40,554 You can't see and by the way, this is exactly the order 89 00:05:40,554 --> 00:05:43,402 in which I did the steps as I was creating this game. 90 00:05:43,402 --> 00:05:46,314 I got to you know, step three and said hey, I should keep track 91 00:05:46,314 --> 00:05:49,520 of this so I can go in the same order when I do the lecture. 92 00:05:49,520 --> 00:05:52,810 So we spawn those chickens but you can't see 'em. 93 00:05:52,810 --> 00:05:55,850 So, we should draw all the game entities. 94 00:05:55,850 --> 00:06:00,800 So, let's go up to the draw. And I'll just uncomment this code. 95 00:06:02,460 --> 00:06:05,530 And you might think reasonably, that I should just be 96 00:06:05,530 --> 00:06:08,420 drawing the rubber chickens at this point, why am I drawing 97 00:06:08,420 --> 00:06:12,920 teddy bears and explosions, because those lists are empty right now and I know it. 98 00:06:12,920 --> 00:06:15,428 To be honest, when I came here I said, I might 99 00:06:15,428 --> 00:06:18,992 as well draw everything right now while I'm thinking about it, 100 00:06:18,992 --> 00:06:22,424 rather than waiting until later and realizing I forgot to draw 101 00:06:22,424 --> 00:06:26,966 the explosion and then coming down and, you know, spending debugging time. 102 00:06:26,966 --> 00:06:30,405 So I did it when I thought of it. 103 00:06:30,405 --> 00:06:33,680 And now, now that I've uncommented this I can run it. 104 00:06:35,090 --> 00:06:37,530 And we see a row of rubber, beautiful, 105 00:06:37,530 --> 00:06:39,850 beautiful rubber chickens along the bottom of the screen. 106 00:06:41,440 --> 00:06:42,090 Okay. 107 00:06:42,090 --> 00:06:47,010 So now, I have drawn all the game entities. 108 00:06:49,830 --> 00:06:53,910 So the next thing says, comments for all the updates that need to happen. 109 00:06:53,910 --> 00:06:57,960 So at this point, I started thinking about how the game would really work and 110 00:06:57,960 --> 00:07:03,260 I went up to the update method and I put up a set of comments. 111 00:07:03,260 --> 00:07:05,680 I said, you know, make sure you update all the game 112 00:07:05,680 --> 00:07:08,080 entities, check for collisions between chickens 113 00:07:08,080 --> 00:07:10,920 and bears, clear out dead teddies. 114 00:07:10,920 --> 00:07:15,270 The sequence of steps that I knew would need to happen on every 115 00:07:15,270 --> 00:07:17,750 update once the full game was running. 116 00:07:17,750 --> 00:07:19,820 We'll just look at those comments as we go along because 117 00:07:19,820 --> 00:07:23,760 it's hard to see them with all the code interspersed between them. 118 00:07:23,760 --> 00:07:30,340 But this was stopping and thinking and not writing any code, just sort of, capturing 119 00:07:30,340 --> 00:07:34,590 my ideas about the sequence of events that had to happen in that update method. 120 00:07:35,690 --> 00:07:40,280 So I did that and now we should update all the game entities. 121 00:07:40,280 --> 00:07:40,420 So 122 00:07:40,420 --> 00:07:44,670 I'll scroll up to the update method, as you can see, there's lots of code in here, 123 00:07:46,070 --> 00:07:52,569 but here's the upfate the game entities, and so I'll uncomment all of this. 124 00:07:53,900 --> 00:07:58,520 And really I wanted to update the chicken because, you know, once I drew 125 00:07:58,520 --> 00:08:02,190 chickens I wanted to click on them and I clicked on them and nothing happened. 126 00:08:02,190 --> 00:08:05,500 And so I was upset, and so 127 00:08:05,500 --> 00:08:08,000 I went and implemented this. 128 00:08:08,000 --> 00:08:11,530 And because I was updating the chickens, I knew everything would need to be updated. 129 00:08:11,530 --> 00:08:17,720 So I just added updating all of them now I made a comment here, by the way, 130 00:08:17,720 --> 00:08:22,850 that I changed the rubber chicken speed for finer granularity. 131 00:08:22,850 --> 00:08:24,270 So let's go to the rubber chicken. 132 00:08:25,720 --> 00:08:31,910 So in this field that is rubber chicken speed, I made it a float, and 133 00:08:31,910 --> 00:08:33,140 I made it 0.8 f. 134 00:08:34,280 --> 00:08:36,490 the f is required because it's a float; 135 00:08:36,490 --> 00:08:39,450 otherwise, the compiler will think 0.8 is a double. 136 00:08:40,520 --> 00:08:44,200 So I've made that a float, and I realized, when 137 00:08:44,200 --> 00:08:47,330 I was doing that, that I regularly make the speed a 138 00:08:47,330 --> 00:08:51,870 float because we usually want to have finer control over 139 00:08:51,870 --> 00:08:57,280 the speed of our game entities than integers provides to us. 140 00:08:57,280 --> 00:09:03,170 So now if I F5 it, I can click on a rubber chicken and he flies up, and I can, you 141 00:09:03,170 --> 00:09:05,620 know, click on all the ru-, well not all, I'll get 142 00:09:05,620 --> 00:09:08,510 bored, but I can click on rubber chickens to launch them. 143 00:09:09,600 --> 00:09:13,390 And so, now, we've noticed that we are, well, we've 144 00:09:13,390 --> 00:09:16,880 noticed, because I just said we're updating all the game entities. 145 00:09:19,510 --> 00:09:22,880 And the next thing is, when a chicken flies out 146 00:09:22,880 --> 00:09:26,260 of the top of the window, we should do something. 147 00:09:26,260 --> 00:09:31,770 We should either remove that chicken from the game, make it inactive, so 148 00:09:31,770 --> 00:09:37,030 that you know, we clean out the dead rubber chickens later, and it's reclaimed. 149 00:09:37,030 --> 00:09:39,041 And, and that's a perfectly reasonable thing to do. 150 00:09:39,041 --> 00:09:41,777 And in fact in the optional project, you will 151 00:09:41,777 --> 00:09:44,657 be, if you choose to do it, you'll be removing 152 00:09:44,657 --> 00:09:50,010 inactive projectiles, from the game. Now for chickens, the way 153 00:09:50,010 --> 00:09:55,290 I wanted this to work is, I pretty much always wanted the bottom 154 00:09:55,290 --> 00:10:01,090 row of chickens to be full. Let's see, that's not exactly correct. 155 00:10:01,090 --> 00:10:04,570 For each, think of it as 20 columns. 156 00:10:04,570 --> 00:10:07,270 Here, why don't I run it and then we can look at it. 157 00:10:07,270 --> 00:10:10,100 So, I wanted 158 00:10:10,100 --> 00:10:13,910 there always to be a chicken in this zeroth column. 159 00:10:13,910 --> 00:10:17,480 So either he's sitting down here, or he's flying his way up. 160 00:10:17,480 --> 00:10:22,530 But once he's gotten to the top and outside the window, I wanted a new chicken 161 00:10:22,530 --> 00:10:27,570 to be put here, so that you always had each column have a chicken in it. 162 00:10:27,570 --> 00:10:35,070 So, the problem, or one of the alternatives was to destroy the chicken, 163 00:10:35,070 --> 00:10:36,940 and spawn a new one. 164 00:10:36,940 --> 00:10:41,620 However, what I decided to do instead was this. 165 00:10:41,620 --> 00:10:44,476 Let's go to the check for chicken leaving the window. 166 00:10:44,476 --> 00:10:49,675 Right here. Instead of 167 00:10:49,675 --> 00:10:56,180 destroying it, I decided to move that chicken 168 00:10:56,180 --> 00:11:00,240 back down to the bottom of the column. And so you'll 169 00:11:00,240 --> 00:11:03,400 notice I added a reset method to Rubber Chicken so 170 00:11:03,400 --> 00:11:07,880 we can go to the definition of that reset method here. 171 00:11:07,880 --> 00:11:10,160 And so it puts the chicken back at the bottom of the 172 00:11:10,160 --> 00:11:15,960 window It sets its velocity back to zero, and it makes moving false. 173 00:11:15,960 --> 00:11:17,365 And just so you know, 174 00:11:17,365 --> 00:11:17,700 [LAUGH] 175 00:11:17,700 --> 00:11:21,710 I originally had this as a set y rather than a reset. 176 00:11:21,710 --> 00:11:24,910 So, I just moved the chicken back to the bottom of the window. 177 00:11:24,910 --> 00:11:27,094 And because the velocity was still positive, 178 00:11:27,094 --> 00:11:28,998 and because it was still moving, it just 179 00:11:28,998 --> 00:11:32,358 kept scrolling up, so it would, you know, pop down to the bottom and go 180 00:11:32,358 --> 00:11:35,326 up, and pop down to the bottom and go up, and while that was very 181 00:11:35,326 --> 00:11:39,216 hypnotic, I didn't like it cause it wasn't how the game was supposed to work. 182 00:11:39,216 --> 00:11:43,480 So I had to change this to reset. So notice. 183 00:11:43,480 --> 00:11:46,960 Right, that it's okay, we develop, we design and implement our 184 00:11:46,960 --> 00:11:50,650 classes, and then when we start using them, we may well 185 00:11:50,650 --> 00:11:54,290 discover that there were things that we didn't know we needed 186 00:11:54,290 --> 00:11:57,850 and we discover we need em as we start using the code. 187 00:11:57,850 --> 00:12:01,850 It's a perfectly natural part of developing games. 188 00:12:01,850 --> 00:12:05,490 And so, I felt perfectly free to add 189 00:12:05,490 --> 00:12:09,190 methods as I needed them throughout the code. 190 00:12:09,190 --> 00:12:12,770 Okay, so why did I move the chicken down to the 191 00:12:12,770 --> 00:12:17,190 bottom again instead of just destroying it and creating a new one? 192 00:12:17,190 --> 00:12:19,160 Because this is better for memory. 193 00:12:19,160 --> 00:12:22,970 There's no need to throw away the chicken to the garbage collector has to go 194 00:12:22,970 --> 00:12:28,750 pick it up, just be...just so I can create a new chicken in the same column. 195 00:12:28,750 --> 00:12:31,570 I can just move this chicken right back down, 196 00:12:31,570 --> 00:12:34,630 and so that saves us a little bit on memory. 197 00:12:34,630 --> 00:12:37,230 So, we've done the replacing chickens part. 198 00:12:40,110 --> 00:12:44,725 And at that point, I could shoot chickens, I could launch chickens up toward the top 199 00:12:44,725 --> 00:12:49,291 of the window, and then when they exited the window, they came back to the bottom. 200 00:12:49,291 --> 00:12:52,310 So, let me run that to show you. 201 00:12:52,310 --> 00:12:54,930 So, I can send a chicken, and when he's out, I 202 00:12:54,930 --> 00:12:58,239 get a new chicken, really the same chicken, back in that column. 203 00:12:59,310 --> 00:13:02,350 This has turned out to be another long lecture, 204 00:13:02,350 --> 00:13:05,040 so, I'm breaking this one into two parts as well. 205 00:13:05,040 --> 00:13:07,000 This is the end of part one.