1 00:00:08,360 --> 00:00:11,440 Remember I broke this lecture into two parts. 2 00:00:11,440 --> 00:00:16,550 So this is the start of part two for the lecture I started last time. 3 00:00:16,550 --> 00:00:20,670 Okay, but at this point, I didn't really have anything 4 00:00:20,670 --> 00:00:23,320 to launch my chickens at, and these are ranged weapons. 5 00:00:23,320 --> 00:00:25,170 I mean, you gotta shoot 'em at something. 6 00:00:25,170 --> 00:00:28,790 And of course, teddy bears are the something that we should shoot them at. 7 00:00:28,790 --> 00:00:33,700 So the next thing I wanted to do, was to actually start spawning teddy bears. 8 00:00:33,700 --> 00:00:36,780 To do that, here in the update method, 9 00:00:41,510 --> 00:00:47,550 I implemented the timer stuff that we have seen numerous times already. 10 00:00:48,730 --> 00:00:52,730 Now a couple of comments about what I was 11 00:00:52,730 --> 00:00:55,640 thinking about and doing as I went through this code. 12 00:00:55,640 --> 00:00:58,960 First of all, I added a new constructor to the teddy bear class. 13 00:00:58,960 --> 00:01:04,910 I didn't have one that I could pass in the sprite, the texture 2D and the velocity. 14 00:01:04,910 --> 00:01:06,630 I had one that I could I pass in a content 15 00:01:06,630 --> 00:01:10,600 manager and a sprite name and a velocity, but that isn't what I wanted to do. 16 00:01:10,600 --> 00:01:12,640 So I added a new constuctor. 17 00:01:12,640 --> 00:01:17,550 When I did that, I felt horribly guilty, because if you go look at 18 00:01:17,550 --> 00:01:22,250 that code, there are four constructors that have lots of duplicated code in them. 19 00:01:22,250 --> 00:01:24,990 And as we learned over the previous 20 00:01:24,990 --> 00:01:28,150 lessons in this module, there's a better way. 21 00:01:28,150 --> 00:01:31,900 And in fact, it was in the die class that we discovered 22 00:01:31,900 --> 00:01:34,320 that there's a better way to consolidate 23 00:01:34,320 --> 00:01:37,030 that code, even when we're dealing with constructors. 24 00:01:37,030 --> 00:01:40,780 We should have the constructors call each other using this. 25 00:01:40,780 --> 00:01:43,290 I didn't do that, I feel horribly guilty. 26 00:01:43,290 --> 00:01:46,830 You should, you know, feel bad as well, as you read that code. 27 00:01:46,830 --> 00:01:51,820 Those constructors should be cleaned up, absolutely, I just didn't do it. 28 00:01:51,820 --> 00:01:55,660 The other thing that I did was, I turned off teddy bear bouncing. 29 00:01:55,660 --> 00:01:56,910 I didn't want the teddy bears 30 00:01:56,910 --> 00:02:00,936 to be bouncing around in the screen anymore, I just wanted them to be spawned. 31 00:02:00,936 --> 00:02:08,920 Okay, so because when I did the draw method I drew all the game entities. 32 00:02:08,920 --> 00:02:13,490 And when I did the update method, I update all the game entities. 33 00:02:13,490 --> 00:02:16,700 Now if I F5, I actually get teddy bears spawned. 34 00:02:16,700 --> 00:02:18,840 And I'm very excited and I shoot rubber chickens at them, 35 00:02:18,840 --> 00:02:21,580 and of course nothing happens because I haven't coded that yet. 36 00:02:21,580 --> 00:02:22,190 And I'm 37 00:02:22,190 --> 00:02:25,410 sad again because, here are these teddies, just begging to 38 00:02:25,410 --> 00:02:28,670 be hit with rubber chickens, and I can't do it. 39 00:02:28,670 --> 00:02:29,270 Very sad. 40 00:02:29,270 --> 00:02:33,320 But we have completed the spawning teddy bears step. 41 00:02:34,570 --> 00:02:38,320 We also need to, because teddy bears don't bounce anymore, we 42 00:02:38,320 --> 00:02:41,990 need to deactivate the teddy bears when they exit the window. 43 00:02:41,990 --> 00:02:44,900 So check for teddy bear leaving window. 44 00:02:44,900 --> 00:02:45,660 All in common, 45 00:02:48,300 --> 00:02:52,700 so now, if the collision rectangle for the top of the teddy bear 46 00:02:52,700 --> 00:02:57,450 is greater than window height, that means that teddy bear's below the window. 47 00:02:57,450 --> 00:03:01,020 And so I just de-activate it, and we'll clean out that teddy's later. 48 00:03:01,020 --> 00:03:06,260 So, unlike the chicken, where we wanted to just keep that chicken 49 00:03:06,260 --> 00:03:11,550 object around to save memory, this teddy bear, there's no reason to save it around. 50 00:03:11,550 --> 00:03:13,600 We'll just deactivate it and, and 51 00:03:13,600 --> 00:03:14,160 clean it up. 52 00:03:15,450 --> 00:03:18,590 So, we've done the next step where I deactivated 53 00:03:18,590 --> 00:03:22,620 teddy bears outside the window, and cleaning out dead teddies 54 00:03:24,890 --> 00:03:29,730 is exactly the way we cleaned out dead teddies before. 55 00:03:30,770 --> 00:03:35,680 So, you can in fact, the way you can know that a 56 00:03:35,680 --> 00:03:39,340 teddy bear has actually been cleaned out, is we will let one. 57 00:03:39,340 --> 00:03:44,430 This will be testing both the deactivate the teddy, and removing 58 00:03:44,430 --> 00:03:50,070 inactive teddies. So there we have removed that teddy bear. 59 00:03:52,470 --> 00:03:54,440 I have to believe, right, so, the teddy 60 00:03:54,440 --> 00:03:57,720 bears are actually dying because of their timer. 61 00:03:57,720 --> 00:04:01,060 So that doesn't actually test going out the bottom of the window. 62 00:04:01,060 --> 00:04:06,360 So we should go change how long a teddy bear lives, so 63 00:04:06,360 --> 00:04:08,920 that it can get all the way to the bottom of the window. 64 00:04:10,040 --> 00:04:12,670 So let's make teddy bears live you know, 15 seconds. 65 00:04:12,670 --> 00:04:15,900 It's very unlikely they'll actually survive 66 00:04:15,900 --> 00:04:17,560 that long, especially once I can shoot 67 00:04:17,560 --> 00:04:18,254 rubber chickens. 68 00:04:18,254 --> 00:04:22,070 And let me, you can actually add break points while 69 00:04:22,070 --> 00:04:23,930 the game is running if you're quick enough about it. 70 00:04:25,030 --> 00:04:26,900 And so I've added it so that this teddy 71 00:04:26,900 --> 00:04:29,900 bear here, once he's left the window he gets removed. 72 00:04:29,900 --> 00:04:34,040 So, we've tested that. We've made sure that both the teddy bear 73 00:04:34,040 --> 00:04:40,980 going outside of the window deactivates it, and that dead teddies are cleaned out. 74 00:04:40,980 --> 00:04:42,690 So let's change that teddy bear life back 75 00:04:42,690 --> 00:04:43,290 to five. 76 00:04:43,290 --> 00:04:47,130 Again, we regularly change our code as we're 77 00:04:47,130 --> 00:04:50,990 testing, just to temporarily test out certain things. 78 00:04:50,990 --> 00:04:52,410 So we've cleaned out the dead teddies. 79 00:04:54,260 --> 00:04:57,190 And you'll notice I've been doing this in small steps. 80 00:04:57,190 --> 00:05:01,330 But those small steps are sort of in larger chunks, if you will. 81 00:05:01,330 --> 00:05:03,699 So the first chunk was getting rubber chickens working. 82 00:05:04,810 --> 00:05:07,680 And the second chunk was getting teddy bears working. 83 00:05:07,680 --> 00:05:12,350 And now, the third chunk, this is not a game development term 84 00:05:12,350 --> 00:05:14,775 by the way, this is just the way I'm thinking of it. 85 00:05:14,775 --> 00:05:15,060 [LAUGH] 86 00:05:15,060 --> 00:05:20,320 So, the third thing is the interactions between teddy bears and chickens. 87 00:05:21,680 --> 00:05:23,680 So this is the collision stuff. 88 00:05:23,680 --> 00:05:25,240 So we'll go back to game one. 89 00:05:25,240 --> 00:05:26,760 We'll go back into the update method. 90 00:05:26,760 --> 00:05:31,168 And this is absolutely the biggest piece of code, as you can see here. 91 00:05:31,168 --> 00:05:36,410 So, this is, first of all, let me uncomment it. 92 00:05:42,630 --> 00:05:44,590 So these are nested loops. 93 00:05:44,590 --> 00:05:47,700 I made a comment about nested loops, though you hadn't seen any yet. 94 00:05:48,740 --> 00:05:50,470 And I talked about, you know, processing a 95 00:05:50,470 --> 00:05:53,530 two dimensional game board like tic-tac-toe or something. 96 00:05:53,530 --> 00:05:55,610 And by the way, the code that was in 97 00:05:55,610 --> 00:05:59,450 the tic-tac-toe programming assignment now you should absolutely be 98 00:05:59,450 --> 00:06:02,240 able to understand those nested four loops that I 99 00:06:02,240 --> 00:06:05,510 gave to you, because we hadn't talked about those yet. 100 00:06:05,510 --> 00:06:08,370 These are, in fact, nested four loops nested 101 00:06:08,370 --> 00:06:11,584 loops anyway, although the inner one is a four 102 00:06:11,584 --> 00:06:13,840 h loop and the outer one is a four loop. 103 00:06:13,840 --> 00:06:16,210 I actually had em both as for each loops, 104 00:06:16,210 --> 00:06:19,420 and then we'll see that I create a new chicken. 105 00:06:19,420 --> 00:06:21,360 And when I added the chicken to my 106 00:06:21,360 --> 00:06:24,510 chickens collection right here, my code blew up 107 00:06:24,510 --> 00:06:27,200 just as I warned you it would, because 108 00:06:27,200 --> 00:06:30,940 I was changing the collection inside for each loop. 109 00:06:30,940 --> 00:06:33,490 So I changed this to a four loop, because I 110 00:06:33,490 --> 00:06:36,890 might add a chicken. So these are nested loops. 111 00:06:36,890 --> 00:06:39,190 For every chicken, we're going to take the 112 00:06:39,190 --> 00:06:42,280 first chicken and compare it to every bear. 113 00:06:42,280 --> 00:06:45,960 Then we're going to take the second chicken, and compare it to every bear. 114 00:06:45,960 --> 00:06:49,000 And then we're going to take the third chicken, and compare it to every bear. 115 00:06:49,000 --> 00:06:51,390 You can see why this collision detection thing can get 116 00:06:51,390 --> 00:06:55,780 pretty computationally intense if you have a lot of game objects. 117 00:06:55,780 --> 00:06:59,060 Okay, this is standard stuff. Both things are active and 118 00:06:59,060 --> 00:07:05,110 the collision rectangles intersect So we detected a collision, and I want to apply 119 00:07:05,110 --> 00:07:09,090 damage to the bear, and I want to explode the bear as appropriate. 120 00:07:09,090 --> 00:07:10,200 So I added a 121 00:07:12,670 --> 00:07:17,470 health food, I added a health food. I added a health field to the bear. 122 00:07:17,470 --> 00:07:24,350 Bear starts at 100 health, and I also added a take damage method to the bear. 123 00:07:24,350 --> 00:07:28,100 Which reduces the bear's health by the damage amount, and if the health 124 00:07:28,100 --> 00:07:31,305 is less than or equal to zero, I clamp the health to 0. 125 00:07:31,305 --> 00:07:33,750 because we don't want negative health, even for 126 00:07:33,750 --> 00:07:37,120 dead teddy bears, and I deactivated the bear. 127 00:07:37,120 --> 00:07:38,590 So he'll get 128 00:07:38,590 --> 00:07:42,710 cleaned out of that teddy bears list in the game one update method. 129 00:07:42,710 --> 00:07:43,860 Let me go back here. 130 00:07:43,860 --> 00:07:50,250 And so what I want though is, I want the teddy bear to take multiple hits to die. 131 00:07:50,250 --> 00:07:53,980 So I make em take damage and I check to see if he's inactive. 132 00:07:53,980 --> 00:07:58,260 And if he's inactive, then I'm going to start playing an explosion. 133 00:07:58,260 --> 00:07:59,730 This time it's going to be great. 134 00:07:59,730 --> 00:08:02,950 both the teddy bears and the projectiles will blow up. 135 00:08:02,950 --> 00:08:03,900 Rubber chickens 136 00:08:03,900 --> 00:08:07,730 will blow up when we have that collision. Okay. 137 00:08:07,730 --> 00:08:14,510 So, let me comment this out and show you this cool bug 138 00:08:14,510 --> 00:08:18,040 that I ran into when I tried testing with the above in place. 139 00:08:18,040 --> 00:08:22,370 So, I put this stuff in place, but I hadn't implemented this yet, 140 00:08:22,370 --> 00:08:25,270 because, you know, you write a little code and then you test it. 141 00:08:25,270 --> 00:08:28,470 And so, it took me a few minutes to figure out what was going on here, 142 00:08:28,470 --> 00:08:34,010 because even though the chickens only inflict 50 damage, and the 143 00:08:34,010 --> 00:08:38,830 teddy bears have 100 health, I was killing these with one shot. 144 00:08:38,830 --> 00:08:41,210 And that is absolutely incorrect. 145 00:08:42,750 --> 00:08:44,780 Here's the issue. 146 00:08:44,780 --> 00:08:53,350 Because I hadn't implemented this code yet, I wasn't making the chicken inactive. 147 00:08:53,350 --> 00:08:57,850 So on one update, the chicken hits the teddy bear, the 148 00:08:57,850 --> 00:09:01,290 teddy bear takes damage, so now he's down to 50 help. 149 00:09:01,290 --> 00:09:04,420 He's still active though, and I loop around to 150 00:09:04,420 --> 00:09:07,020 the next update, a 60th of a second later. 151 00:09:08,020 --> 00:09:12,490 And because the chicken is still active, this evaluates to true. 152 00:09:13,610 --> 00:09:16,260 So, I hit the bear, same chicken. 153 00:09:16,260 --> 00:09:19,400 Same chicken damages the bear again because, 154 00:09:19,400 --> 00:09:20,660 oh, this is horrible. 155 00:09:20,660 --> 00:09:26,260 The rubber chicken is passing through the teddy bear, ugh, every update. 156 00:09:26,260 --> 00:09:30,420 And so that's why, I was getting one shot 157 00:09:30,420 --> 00:09:33,480 kills of bears even though I had attempted to implement 158 00:09:35,730 --> 00:09:36,380 two hits per death. 159 00:09:36,380 --> 00:09:36,497 [LAUGH] 160 00:09:36,497 --> 00:09:37,690 Two hits per death. How's that for a slogan? 161 00:09:37,690 --> 00:09:40,210 So once I put this back in. 162 00:09:42,700 --> 00:09:47,050 So now I've made it so the chicken will become inactive on this collision. 163 00:09:48,330 --> 00:09:51,500 Chickens always die on a collision, there's no two hit chicken death. 164 00:09:51,500 --> 00:09:52,850 So we explode 165 00:09:54,940 --> 00:09:55,230 it. 166 00:09:55,230 --> 00:09:59,630 And we're going to add a new chicken down at the bottom of the column. 167 00:09:59,630 --> 00:10:03,550 So, I thought about moving this particular chicken down to 168 00:10:03,550 --> 00:10:06,420 the bottom again, but it made less sense to me. 169 00:10:06,420 --> 00:10:10,249 When a chicken leaves the window, it makes sense to me to drag it back. 170 00:10:11,490 --> 00:10:14,200 Once you explode a chicken, it really doesn't make 171 00:10:14,200 --> 00:10:17,440 sense to me to move that exploded chicken around. 172 00:10:17,440 --> 00:10:19,990 You certainly could do it, exactly the way we did 173 00:10:19,990 --> 00:10:24,030 it when a chicken left the window, but I added a new one in this case. 174 00:10:24,030 --> 00:10:27,550 And I made sure here that the new one that 175 00:10:27,550 --> 00:10:31,660 I was adding was in the same column, same x location. 176 00:10:31,660 --> 00:10:34,810 Here's another one of those calls to get chicken start y. 177 00:10:34,810 --> 00:10:36,050 This is where I added it. 178 00:10:36,050 --> 00:10:37,790 When I got here I said, holy smokes. 179 00:10:37,790 --> 00:10:41,450 I need to write a method for that, and chicken damage like that. 180 00:10:41,450 --> 00:10:45,527 So now we will see that teddy 181 00:10:45,527 --> 00:10:52,020 bears take two hits to die. One, two. 182 00:10:52,020 --> 00:10:53,390 Oh my gosh. 183 00:10:53,390 --> 00:10:55,720 We still aren't quite done, as you can see, because the 184 00:10:55,720 --> 00:11:00,230 chicken, we get explosions, but then the chicken keeps flying up. 185 00:11:00,230 --> 00:11:03,020 We'll figure out what's going on there momentarily. 186 00:11:03,020 --> 00:11:05,220 But if we go back to the Powerpoint, we can 187 00:11:05,220 --> 00:11:09,110 see that this collision stuff had a lot of special processing. 188 00:11:09,110 --> 00:11:11,130 We had nested loops, 189 00:11:11,130 --> 00:11:13,920 which we hadn't seen before, though we'd talked about. 190 00:11:13,920 --> 00:11:16,830 We had multiple hits to kill a teddy bear, 191 00:11:16,830 --> 00:11:21,430 which was buggy at first until we completely implemented that. 192 00:11:21,430 --> 00:11:23,700 We have both teddies and chickens exploding, 193 00:11:23,700 --> 00:11:27,190 so you got the gratuitous extra explosions. 194 00:11:27,190 --> 00:11:28,470 There was that cool bug. 195 00:11:28,470 --> 00:11:32,150 And that may seem weird talking about a cool bug, but they're mysteries right? 196 00:11:32,150 --> 00:11:37,260 You go solve these mysteries and that's part of the fun of programming. 197 00:11:37,260 --> 00:11:40,370 And then there was some special chicken processing, 198 00:11:40,370 --> 00:11:45,040 the part where I made the chicken inactive, but 199 00:11:45,040 --> 00:11:47,050 also added a new chicken to make sure I 200 00:11:47,050 --> 00:11:49,030 always had a chicken in one of those columns. 201 00:11:50,620 --> 00:11:52,530 Just a couple more things. 202 00:11:52,530 --> 00:11:57,750 So the chicken kept moving forward, even after we started the explosion 203 00:11:57,750 --> 00:12:01,970 at the middle of the chicken, because we aren't cleaning out dead chickens. 204 00:12:03,230 --> 00:12:03,560 So 205 00:12:03,560 --> 00:12:05,630 I have come to this part in the code where we do 206 00:12:05,630 --> 00:12:09,310 clean out dead chickens, this is just like cleaning out dead teddy bears. 207 00:12:09,310 --> 00:12:11,290 And so now, we will see that when I shoot a 208 00:12:11,290 --> 00:12:15,590 teddy bear with a chicken, the chicken does not keep going up. 209 00:12:18,180 --> 00:12:20,245 I'm sorry, I just got a little distracted there 210 00:12:20,245 --> 00:12:22,069 because I was shooting rubber chickens at teddy bears. 211 00:12:23,080 --> 00:12:25,940 So, we've now cleaned out the dead rubber chickens, 212 00:12:25,940 --> 00:12:28,660 and there's just one more thing for us to do. 213 00:12:28,660 --> 00:12:31,030 For efficiency, you can't even see this. 214 00:12:31,030 --> 00:12:34,830 But for efficiency, we have those explosions that we cleaned out 215 00:12:34,830 --> 00:12:38,200 before, when we had explosions, and we should do that again. 216 00:12:38,200 --> 00:12:42,050 Once an explosion has played, it becomes inactive. 217 00:12:42,050 --> 00:12:43,320 And so we should get it out 218 00:12:43,320 --> 00:12:44,250 of the list. 219 00:12:44,250 --> 00:12:47,800 I did make a change that I forgot to mention moments ago. 220 00:12:47,800 --> 00:12:51,230 When I create an explosion, if I can find it. 221 00:12:52,580 --> 00:12:56,190 When I create an explosion, I changed the explosion class. 222 00:12:56,190 --> 00:12:58,380 Early on, when we were using explosions, remember, 223 00:12:58,380 --> 00:13:01,050 we had an explosion, and we'd create it, 224 00:13:01,050 --> 00:13:05,160 and then hold it around, and then we'd tell it to play at a particular location. 225 00:13:05,160 --> 00:13:08,370 This is kind of a different way of thinking about explosions, 226 00:13:08,370 --> 00:13:10,890 where you just create the explosion, and play it 227 00:13:10,890 --> 00:13:13,640 right away, and then when it's done, it's done. 228 00:13:13,640 --> 00:13:16,230 And, sort of we know enough now for that 229 00:13:16,230 --> 00:13:19,770 to be an intuitive and doable thing for us. 230 00:13:19,770 --> 00:13:21,971 So, once we've cleaned out the dead 231 00:13:21,971 --> 00:13:24,710 explosions, we are all done with this game. 232 00:13:25,720 --> 00:13:28,020 So, what did we do today? 233 00:13:28,020 --> 00:13:29,960 We used the rubber chicken class and some 234 00:13:29,960 --> 00:13:32,460 of the other classes we had hanging around. 235 00:13:32,460 --> 00:13:33,670 And we built a small 236 00:13:33,670 --> 00:13:39,840 game up step by step following the steps I used to built this small game. 237 00:13:39,840 --> 00:13:43,850 And talking about the concepts we've learned so far in the course as we did it. 238 00:13:45,140 --> 00:13:47,710 So that's the end of Module 11. 239 00:13:47,710 --> 00:13:51,340 We're all done with, well, we're all done 240 00:13:51,340 --> 00:13:55,630 learning the new ideas behind class design and implementation. 241 00:13:55,630 --> 00:13:58,700 And so next time, we'll actually start learning 242 00:13:58,700 --> 00:14:02,540 how to add music and sound effects to our x and a games.