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In this video, we're implementing our damage systems so that blank, 2

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there we go, we can shoot projectiles that kill enemies that have health. 3

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And when they get to zero, they're destroyed. 4

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So, let's jump in and get started. 5

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Okay, let's start off by implementing some colliders. 6

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I'm gonna find my Zucchini and add a component, 7

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which will be a collider, box collider 2D. 8

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I think that's pretty good. 9

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It doesn't need to be perfect with the Zucchini. 10

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I'll edit just a little bit, bring it in. 11

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Bring it down, bring it in just so it's reasonably tight. 12

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Click on the Edit Collider. 13

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Okay, there we go. 14

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Pretty good. It just kinda has to strike the center of 15

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the Zucchini. 16

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We're in lanes, so we don't need super precise collision. 17

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That's great, apply that back to the prefab, excellent. 18

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I think I can remove my Zucchini from the scene now. 19

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We'll just be using prefabs when we instantiate them. 20

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Now, let's find the lizard. 21

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The lizard, I do need to drag a lizard into the scene, so 22

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I can see what's going on. 23

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Click on ADD COMPONENT, Box Collider 2D. 24

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That's around the entire outside, which is a bit big. 25

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I'm gonna switch onto Lizard Walk. 26

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I think that's where I wanna have my collider around wherever he walks, because 27

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during the jump, I think the wizard should be little and even vulnerable. 28

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Jump, jump, jump, jump. 29

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Okay, during that stage, I don't really want my cactus to be hitting it. 30

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So I will just wrap my collider around, what it looks like when he's walking. 31

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So edit collider on the box, collider move this in. 32

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Move that in as well, move that down. 33

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Now move that whoops. 34

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That's bit of a pain when that happens. 35

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Back on Edit Collider. 36

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And there we go, excellent. 37

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Apply that back to the prefab. 38

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Very good, and once again, I don't think I need to my lizard any more. 39

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What I will do is find a Zucchini and find where we, 40

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is Trigger is on the Box Collider 2D. 41

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Is Trigger, tick that on. 42

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Now, one thing we need to review any time we're doing collisions, 43

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is our collision matrix. 44

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So let's have a quick look at that. 45

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We can see all of these grids in here. 46

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We've looked at these before. 47

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We're using a Trigger Static Trigger Collidor, 48

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Dynamic Rigidbody Trigger Collidor, Kinematic Rigidbody Trigger Collidor. 49

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Well it's not static and it's not dynamic, 50

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so it's gonna be a Kinematic Rigidbody Trigger Collidor which reminds me. 51

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We don't have a rigidbody anywhere. 52

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So I'll find my lizard. 53

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And add a rigidbody. 54

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I didn't list that out in my requirements. 55

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This is one of those things when you do the requirements, 56

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you think you're being pretty thorough. 57

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But we missed, that we need a rigidbody. 58

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I'll switch this to kinematic, cuz we're saying walk across the screen this way. 59

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I'm putting a rigidbody onto the lizard. 60

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And we could put a rigidbody on the projectile as well. 61

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Actually, let's do that just so we are being thorough on the Zucchini. 62

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Add Component, RigidBody 2D. 63

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And it's gonna work without this, I believe, but we'll say it's Kinematic. 64

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Now, temporary over into your scripts. 65

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What script are we looking for 66

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here as I move my microphone out of the way a little bit? 67

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I'm looking for the Projectile script. 68

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Open that up in Visual Studio. 69

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Let's start a new line, where we're going to check for the trigger. 70

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So we'll say void OnTriggerEnter2D, 71

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and the auto completes a bunch of stuff for us. 72

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I'm gonna rename from collision here, 73

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this is what's getting passed in, rename to this to otherCollider. 74

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otherCollision, we'll cal it otherCollider. 75

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You can call it whatever you want. 76

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You could call it bob if you wanted to, but 77

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I wanted to just be very clear that we're talking about the other things collider. 78

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So this is the projectile, and when we bump into anything else, 79

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we wanna know details about the anything else, so that's the otherCollider. 80

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No we haven't even done this for 81

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a while still be printing, so Debug .Log, 82

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and then ("I hit: " what do we hit + otherCollider-name). 83

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So we'll just make sure that our collision is working. 84

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Before we go anywhere else on collision, you always wanna make sure [LAUGH] it's 85

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working, or else you scratch your head wondering what's going on. 86

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So back over into here, click on Play. 87

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Once it's finished compiling and thinking, click on Play, open up the Console. 88

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A couple of warnings, we're not using that, that's fine. 89

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And then when this hits here, boing, we should get, I hit a lizard, excellent. 90

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Okay, so collision is successfully working. 91

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That's really important for 92

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us to be confident hat we're on top of that, good stuff. 93

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Okay, so when we have that collision moment, basically in here, 94

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what we wanna be doing is reduce health. 95

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That's what we wanna be doing in here. 96

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So how do we go about doing that? 97

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Well, we would call some sort of say, DealDamage method. 98

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And DealDamage(), we haven't created that yet, 99

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it doesn't know where it's coming from. 100

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So let's go and create all of that mechanism. 101

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So jump back over into Unity, we'll need to make ourselves a new script, 102

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which will be called Health. 103

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Create C# script, Health. 104

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I'll just double click on Health. 105

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Okay, so let's start off by giving ourselves a notion of how much health 106

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the particular thing will have. 107

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So SerializeField, and then this will be a float, 108

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we'll call this health, an issue like that 100f seems pretty good. 109

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Let's have a quick look at our checklist, 110

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we're going through the mechanism now the Health script. 111

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We've created Health script, serialize health, yes, create DealDamage, 112

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let's do that. 113

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So for now, I'm going to just get rid of start and update, 114

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we put them back in if we need them, create a public method, 115

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cuz we need to be accessing this from the projectile. 116

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The projectile's gonna say, I hit something, and we call the Deal Damage, so 117

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we call DealDamage. 118

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And what do we need at this point? 119

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Well we need to know how much damage to deal, 120

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and we want that to be dependent upon the particular projectile that's hit you. 121

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So we'll say, when DealDamage is called, 122

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we require you to let us know of type float how much damage it is, 123

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that you need to be passing back in to DealDamage. 124

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Okay, open our curly braces. 125

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And then within here we'll have 126

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the standard health -= damage;. 127

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So we're saying, whatever health you have at the moment starting up for 128

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the hundred is -= damage that's just being passed through when we call DealDamage. 129

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And then we do our standard if did. 130

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So if you think you know how to do this, 131

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then just if the health gets below zero, destroy the game object. 132

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Just complete that. 133

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Okay, if health is <0, 134

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then We will Destroy(gameObject). 135

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So basically destroying me is what that means. 136

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Whatever me is attached to, whatever this health has been placed onto. 137

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So it's been reasonably good, save that up, jump back over into projectile. 138

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Now, DealDamage, we have a mechanism for calling that. 139

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How are we gonna do that, 140

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well we know that when we collide with the particular thing. 141

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The otherCollider, then at that instance we know who the otherCollider belongs to. 142

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So we don't need to go searching through our entire project and say, 143

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hang on a minute who did I just collide with I just collided with the thing 144

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that owns the collider, so the otherCollider. 145

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This could be called otherObject that currently possesses a collider, but 146

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that's a bit too long. 147

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So, let's start of by creating a variable, which we'll call var, 148

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just a general variable. 149

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var health = otherColider.GetComponent. 150

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And component of type Health. 151

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Now we have a reference to the health component or the health script, so 152

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just remove my comments in here. 153

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Then DealDamage, instead of just DealDamage, we're going to say 154

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health.DealDamage, cuz we're referring to health which is our health component. 155

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And DealDamage, I spelled it incorrectly there. 156

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DealDamage, let me go back over into health and see what I code it. 157

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DealDamage, and the problem is that I'm not passing anything in. 158

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So it's saying we mass over it, it's saying there's no argument. 159

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And that was because we said we need to know how much damage, so 160

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thank you Visual Studio for reminding me of that. 161

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How much damage, well, let's say we need something a serialized damage. 162

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So we'll say damage in here, just kind of damage amount. 163

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Up at the time [SerializeField] float damage. 164

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Initialize that at, say, 50;. 165

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Okay, now it's happy, it's passing, it's calling, hey, DealDamage, I want you to 166

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give 50 points of damage, or whatever it's being changed to in the inspector. 167

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Now, let's jump over and 168

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see if we can get any mechanisms to see what's going on here. 169

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Go to Console, clear our issues, click on Play. 170

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Now, do we have a way to visualize what's going on? 171

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Let's find whichever the first lizard is that comes out. 172

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Let's grab them in our lane that is. 173

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So this guy just here if I can click on New, 174

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excellent, has health somewhere, we haven't added the health script. 175

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What are we crazy? 176

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That's what we are, we need to add the health script so 177

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find your prefab of the lizard. 178

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Click on Add Component, type in health. 179

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Double click on that, I'll single click on that. 180

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That is health, 100, yep that's fine. 181

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Now let we click on Play, I'm gonna select one of the attackers that spawns. 182

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This first, it was probably that guy, 183

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they have already hit him that one, yep, there we go. 184

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Already has 50 health. 185

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That first Zucchini smacked into it and 186

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then second time around, boom, health goes to 0. 187

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Excellent, so we have cactus shooting projectiles that's damaging the lizard. 188

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The lizard health is going down. 189

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We've done that by creating our own trigger, 190

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where we are calling the DealDamage and by having a mechanism that says as health, 191

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as you're hit, then decrease your health until you get to 0. 192

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And then I noticed one little bug which is the fact that we hit 0, so we twice 193

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on 0 health but the attacker wasn't destroyed, and that's cuz we're saying <0. 194

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So we need to say <=0. 195

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We'll try that one more time, click on Play, 196

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hopefully we hit this lizard, 197

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it will be once, and then he did a second time, and it should disappear. 198

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There we go, fantastic. 199

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A few little bits and pieces we can tidy up but that is good for this video. 200

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I think we got our core functionality in. 201

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Let's put in a little bit more of that finesse in the next video. 202

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So see you again shortly.