1 00:00:08,590 --> 00:00:13,500 Here we are in the last lecture for module four about classes and objects. 2 00:00:13,500 --> 00:00:16,850 And as a reminder here are the module learning objectives. 3 00:00:16,850 --> 00:00:18,722 And we've finally gotten to the one we're 4 00:00:18,722 --> 00:00:20,930 go, we're going to design a new class together. 5 00:00:24,290 --> 00:00:25,954 So at this point in the module, 6 00:00:25,954 --> 00:00:29,154 we've discussed the foundational ideas behind the object 7 00:00:29,154 --> 00:00:31,778 oriented paradigm here and we've discussed how 8 00:00:31,778 --> 00:00:34,900 to use those ideas in a C-sharp program. 9 00:00:34,900 --> 00:00:37,195 Now were going to step back from the 10 00:00:37,195 --> 00:00:41,330 programming and do a higher level design activity. 11 00:00:41,330 --> 00:00:42,360 To design a class. 12 00:00:43,540 --> 00:00:47,040 Before we actually do that, you should take this in-lecture quiz. 13 00:00:52,990 --> 00:00:55,270 So, before we can design our rubber 14 00:00:55,270 --> 00:00:58,158 chicken class, we have to think deeply about 15 00:00:58,158 --> 00:01:01,046 our game design, and really decide what role 16 00:01:01,046 --> 00:01:04,460 does the rubber chicken play in our game. 17 00:01:04,460 --> 00:01:08,660 Now you might think That the player avatar would 18 00:01:08,660 --> 00:01:13,530 be an awesome thing to use the rubber chicken for. 19 00:01:13,530 --> 00:01:17,880 Sadly, not this time. 20 00:01:17,880 --> 00:01:22,890 This time we're going to design the rubber chicken as a weapon. 21 00:01:22,890 --> 00:01:25,860 So it won't be a very limited weapon, of course, because 22 00:01:25,860 --> 00:01:29,320 rubber chickens are pretty flexible now I hope you got that. 23 00:01:30,340 --> 00:01:35,185 rubber chickens can be either melee weapons as you can might, as you 24 00:01:35,185 --> 00:01:40,410 might be able to imagine and they can be ranged weapons as well. 25 00:01:40,410 --> 00:01:42,889 So, the way we're going to approach this is 26 00:01:42,889 --> 00:01:45,320 first we're going to think about the state. 27 00:01:48,050 --> 00:01:50,499 What kind of information do we need to 28 00:01:50,499 --> 00:01:55,530 store to capture the characteristics of the rubber chicken? 29 00:01:55,530 --> 00:01:57,560 And then we'll move on to behavior. 30 00:01:59,660 --> 00:02:04,220 Now it's important for you to realize that as we design real classes for 31 00:02:04,220 --> 00:02:09,280 real games we end up iterating between state and behavior as we go along. 32 00:02:09,280 --> 00:02:13,260 We might discover we need some new behavior as we're developing our game. 33 00:02:13,260 --> 00:02:17,900 At which point we probably need to go back and add some more state as well. 34 00:02:17,900 --> 00:02:20,823 So this is sort of a a-typical small example 35 00:02:20,823 --> 00:02:25,300 well we'll cover state and then we'll cover behavior. 36 00:02:25,300 --> 00:02:28,600 So you should now go to the in lecture quiz, which really has 37 00:02:28,600 --> 00:02:33,330 you pause and think about the state of the rubber chicken for a while. 38 00:02:33,330 --> 00:02:35,230 And then come back and we'll talk about it. 39 00:02:39,570 --> 00:02:44,114 Okay, so there is some reasonable state information that we might store for 40 00:02:44,114 --> 00:02:48,830 a rubber chicken that we''re going to use as a weapon in our game. 41 00:02:48,830 --> 00:02:52,214 First of all, we're going to need location we need to know 42 00:02:52,214 --> 00:02:56,790 where the rubber chicken is, so that we can do collision detection. 43 00:02:56,790 --> 00:03:00,944 Especially if you're good at using your rubber chicken weapon, you're 44 00:03:00,944 --> 00:03:04,696 going to actually collide that rubber chicken with other stuff and 45 00:03:04,696 --> 00:03:07,644 the way we actually figure out that that's happened 46 00:03:07,644 --> 00:03:10,330 is by using the location of the rubber chicken. 47 00:03:11,410 --> 00:03:13,706 Rubber chickens also have velocity, especilly 48 00:03:13,706 --> 00:03:16,140 when they're used as a ranged weapon. 49 00:03:16,140 --> 00:03:20,940 So if were to throw the rubber chicken, it has a particular velocity. 50 00:03:20,940 --> 00:03:23,316 And so we're going to need that velocity so 51 00:03:23,316 --> 00:03:26,770 that we can change the rubber chicken's location over time. 52 00:03:28,060 --> 00:03:29,908 We also have a range for the 53 00:03:29,908 --> 00:03:35,210 rubber chicken. How far can you throw it, for example. 54 00:03:35,210 --> 00:03:38,602 And so, you know, you get upgrades, you get rubber chicken upgrades as you 55 00:03:38,602 --> 00:03:43,780 work your way through this Fictional game that hopefully no one will ever build. 56 00:03:43,780 --> 00:03:46,942 So you get these upgrades to your rubber chicken and so you can 57 00:03:46,942 --> 00:03:52,450 fling your rubber chicken further if you increase the range through those upgrades. 58 00:03:52,450 --> 00:03:55,159 Accuracy, you also have accuracy with your rubber 59 00:03:55,159 --> 00:03:57,868 chicken, you can't just fling it in any direction 60 00:03:57,868 --> 00:04:00,136 and then expect it to hit stuff, you need to 61 00:04:00,136 --> 00:04:03,223 actually be good at aiming your rubber chicken, wow there 62 00:04:03,223 --> 00:04:06,940 are some weird things I'm saying today but that's okay. 63 00:04:06,940 --> 00:04:09,325 You have to be able to aim your rubber chicken with some 64 00:04:09,325 --> 00:04:12,440 level of accuracy and again you might be able to upgrade that stuff. 65 00:04:13,650 --> 00:04:15,820 Rubber chickens, when we do get that 66 00:04:15,820 --> 00:04:20,270 collision with something, rubber chickens inflict damage. 67 00:04:20,270 --> 00:04:23,294 Now that damage could be variable right, it could 68 00:04:23,294 --> 00:04:26,630 be based on how far away the rubber chicken was. 69 00:04:26,630 --> 00:04:29,619 Its velocity when it strikes whatever it hits, because if 70 00:04:29,619 --> 00:04:32,364 you use it as a range weapon towards something close, 71 00:04:32,364 --> 00:04:34,682 it will probably do more damage than if you use 72 00:04:34,682 --> 00:04:37,570 it as a range weapon and you throw it far away. 73 00:04:37,570 --> 00:04:40,719 So, there's some damage that's probably variable, 74 00:04:40,719 --> 00:04:44,180 unless we stuff our rubber chicken with C4. 75 00:04:44,180 --> 00:04:45,608 In which case it probably 76 00:04:45,608 --> 00:04:47,920 always inflicts about the same amount of 77 00:04:47,920 --> 00:04:51,520 damage when it hits something and explodes. 78 00:04:51,520 --> 00:04:54,832 The last thing we probably want to store which you may not 79 00:04:54,832 --> 00:04:58,260 of thought of is who is the owner of this rubber chicken. 80 00:04:58,260 --> 00:04:59,748 And it's not because we need you know 81 00:04:59,748 --> 00:05:02,310 somebody to feed and care for this rubber chicken. 82 00:05:02,310 --> 00:05:06,836 It's because usually what happens, especially in games with weapons, 83 00:05:06,836 --> 00:05:10,924 especially in games with ranged weapons, is if you inflict damage 84 00:05:10,924 --> 00:05:15,450 by throwing your rubber chicken towards something and the rubber chicken 85 00:05:15,450 --> 00:05:20,341 hits and destroys, oh, I don't know, something, imagine something, hits 86 00:05:20,341 --> 00:05:25,086 and destroys something usually the owner of that particular projectile, in 87 00:05:25,086 --> 00:05:30,030 this case, will end up getting points or upgrades or something. 88 00:05:30,030 --> 00:05:32,918 Right so you actually need to keep track of who 89 00:05:32,918 --> 00:05:36,186 is the owner of the rubber chicken, so that we could 90 00:05:36,186 --> 00:05:42,440 allocate to those benefits to whoever damaged something with the rubber chicken. 91 00:05:42,440 --> 00:05:46,720 Okay, so if that hasn't been disturbing enough to you. 92 00:05:46,720 --> 00:05:48,290 That's great. Hang with me. 93 00:05:48,290 --> 00:05:50,660 We'll see how much more damage we can do. 94 00:05:50,660 --> 00:05:54,110 So you should now go do another in lecture quiz. 95 00:05:54,110 --> 00:05:58,500 We really think about what kind of behaviors should this rubber chicken have. 96 00:05:58,500 --> 00:06:01,030 And then click continue, and we'll move on together. 97 00:06:05,210 --> 00:06:06,150 Okay. 98 00:06:06,150 --> 00:06:07,919 So there are a number of reasonable 99 00:06:07,919 --> 00:06:10,970 behaviors that this rubber chicken could have. 100 00:06:10,970 --> 00:06:14,290 For example, we're going to want to update this rubber chicken. 101 00:06:14,290 --> 00:06:17,707 Remember we talked, sorry, we haven't talked yet, but we 102 00:06:17,707 --> 00:06:20,454 will talk soon about a game loop where we update to 103 00:06:20,454 --> 00:06:23,201 the game world so that we sort of update the status 104 00:06:23,201 --> 00:06:26,750 of everything in our game world and then we draw it. 105 00:06:26,750 --> 00:06:31,600 So we will want to update the rubber chicken periodically. 106 00:06:31,600 --> 00:06:34,150 Every frame in our game, in general. 107 00:06:34,150 --> 00:06:37,980 So that the location changes based on the velocity. 108 00:06:37,980 --> 00:06:42,070 So we definitely want to the rubber chicken to expose an update behavior. 109 00:06:42,070 --> 00:06:45,600 So that we can change its location as we go along. 110 00:06:45,600 --> 00:06:48,330 We might also want our rubber chicken to exhibit an 111 00:06:48,330 --> 00:06:51,900 explode behavior, so we could call a method telling the. 112 00:06:51,900 --> 00:06:53,780 Rubber chicken to explode. 113 00:06:53,780 --> 00:06:56,660 That really only applies if we're using the whole C4 114 00:06:56,660 --> 00:07:00,210 rubber chicken approach. But, you know, it's worth thinking about. 115 00:07:01,740 --> 00:07:04,120 We also may, if we have a more interesting 116 00:07:04,120 --> 00:07:07,900 game, we may have the rubber chicken play an animation. 117 00:07:07,900 --> 00:07:10,000 It can play one animation as it flies 118 00:07:10,000 --> 00:07:13,385 through the air Another animation right before it realizes 119 00:07:13,385 --> 00:07:15,695 it is going to explode because rubber chickens are 120 00:07:15,695 --> 00:07:18,330 pretty self aware and they know that's going to happen. 121 00:07:19,834 --> 00:07:21,682 and a variety of other animations 122 00:07:21,682 --> 00:07:23,100 just for humor. 123 00:07:23,100 --> 00:07:25,557 If you're building a game with rubber chicken 124 00:07:25,557 --> 00:07:28,890 weapons, you probably are keying into the humor idea. 125 00:07:28,890 --> 00:07:32,160 So playing some animations might be interesting. 126 00:07:32,160 --> 00:07:37,230 I have in fact done this class design exercise in a sort of normal. 127 00:07:37,230 --> 00:07:39,302 Well not a normal classroom, a classroom of 128 00:07:39,302 --> 00:07:42,500 my game development students, let's put it that way. 129 00:07:42,500 --> 00:07:46,724 And so I felt compelled to tell you that there is one unreasonable behavior, 130 00:07:46,724 --> 00:07:49,080 at least for the rubber chicken. 131 00:07:49,080 --> 00:07:53,970 And most rubber chickens are not going to in fact turn into a live chicken. 132 00:07:53,970 --> 00:07:55,380 Sometime in the game. 133 00:07:55,380 --> 00:07:57,290 That would just be wrong. 134 00:07:57,290 --> 00:08:01,550 This is not Pinocchio with rubber chickens, so we we're probably 135 00:08:01,550 --> 00:08:06,070 not going to convert our rubber chicken into a live chicken. 136 00:08:06,070 --> 00:08:11,790 Okay, so that was sort of a short and sweet what thought process do 137 00:08:11,790 --> 00:08:17,290 we go through to actually design the classes in our game. 138 00:08:17,290 --> 00:08:20,878 And that's probably enough for sort of the informal figuring 139 00:08:20,878 --> 00:08:23,928 out what you need as you build classes in your games. 140 00:08:23,928 --> 00:08:28,328 More advanced object-oriented analysis and design has, 141 00:08:28,328 --> 00:08:31,760 uses much more formal tools to actually figure 142 00:08:31,760 --> 00:08:36,952 out state and behavior and so on, and so in later classes that I teach at 143 00:08:36,952 --> 00:08:41,090 UCCS, we actually cover those kinds of things. 144 00:08:41,090 --> 00:08:43,718 But this sort of informal thinking about it 145 00:08:43,718 --> 00:08:47,806 kind of process, including understanding that you're probably 146 00:08:47,806 --> 00:08:50,799 going to iterate in practice, is, is a reasonable 147 00:08:50,799 --> 00:08:54,890 first taste towards how we actually design stuff. 148 00:08:54,890 --> 00:08:58,240 So, that's the end of module four. 149 00:08:58,240 --> 00:09:02,141 Next time, we'll actually move on to talking about the 150 00:09:02,141 --> 00:09:03,320 XNA framework.