1 00:00:12,325 --> 00:00:15,900 OK. Hi everyone. Welcome back to this tutorial 2 00:00:15,900 --> 00:00:19,375 OK, let's go back to the Unreal Engine 4 Editor 3 00:00:19,375 --> 00:00:22,325 Let's review what we made in the last lesson first 4 00:00:22,325 --> 00:00:25,275 We have implemented AI basic turning in the last lesson 5 00:00:25,275 --> 00:00:30,375 Now our AI will turn to wherever player goes 6 00:00:30,375 --> 00:00:32,300 This is a simple mechanism 7 00:00:32,300 --> 00:00:34,806 In this lesson, we will create another mechanism 8 00:00:34,831 --> 00:00:37,450 That is, when seeing the player drawing a sword 9 00:00:37,450 --> 00:00:43,550 The AI is told to get ready to fight 10 00:00:43,550 --> 00:00:45,375 This is rather simple 11 00:00:45,375 --> 00:00:46,850 Now I find a problem 12 00:00:46,850 --> 00:00:54,125 That is, as soon as our camera moves to our AI's body 13 00:00:54,125 --> 00:00:56,200 It makes a collision 14 00:00:56,200 --> 00:00:58,975 For example, flashing like this 15 00:00:58,975 --> 00:01:01,025 This is due to the collision 16 00:01:01,025 --> 00:01:06,525 Our camera arm is about five meters 17 00:01:06,525 --> 00:01:09,350 so the body of AI will be captured 18 00:01:09,350 --> 00:01:11,850 and there will be a collision 19 00:01:11,850 --> 00:01:14,475 Now I want to modify this object 20 00:01:14,475 --> 00:01:20,600 Sometimes our camera arm also collides with our player 21 00:01:20,600 --> 00:01:23,100 We can modify it here 22 00:01:23,100 --> 00:01:27,625 Click the Collision Presents here and set it to Custom 23 00:01:27,625 --> 00:01:30,525 Then turn off the Camera 24 00:01:30,660 --> 00:01:35,935 Similarly, select the Camera and set it as Not 25 00:01:35,975 --> 00:01:40,300 Then let's find our AI and apply the same setting 26 00:01:40,325 --> 00:01:44,200 Because our camera will collide with the objects 27 00:01:44,200 --> 00:01:47,600 Just turn off the Camera and ignore it 28 00:01:47,600 --> 00:01:48,850 Now let's have a try 29 00:01:48,850 --> 00:01:50,200 Draw the sword 30 00:01:50,225 --> 00:01:51,240 OK 31 00:01:51,550 --> 00:01:53,375 Now there is no problem 32 00:01:53,375 --> 00:01:55,800 There is no problem when the base role attacks 33 00:01:55,800 --> 00:01:57,975 and when the camera goes back here 34 00:01:57,975 --> 00:01:59,450 OK 35 00:01:59,450 --> 00:02:01,625 OK, we have realized this simple function 36 00:02:01,625 --> 00:02:03,100 Now let's implement another one 37 00:02:03,100 --> 00:02:06,550 which is to create a Animation Blueprints for AI 38 00:02:06,550 --> 00:02:09,425 so that it will have an animation just like the player 39 00:02:09,425 --> 00:02:13,150 Otherwise it will be strange to keep it in this T-Pose 40 00:02:13,150 --> 00:02:16,225 Now let's go back to the Content Browser 41 00:02:16,225 --> 00:02:18,650 Find the Animation Blueprints of character 42 00:02:18,650 --> 00:02:24,159 AI blueprint is copied from the character blueprint 43 00:02:24,183 --> 00:02:26,400 in order to animate it 44 00:02:26,400 --> 00:02:28,800 OK, let's open this Animation Blueprint 45 00:02:28,800 --> 00:02:30,425 Put it here 46 00:02:30,600 --> 00:02:33,875 Let's see which variables to apply 47 00:02:33,875 --> 00:02:37,200 Actually we only need to use two variables 48 00:02:37,225 --> 00:02:39,600 from the character's blueprint 49 00:02:39,600 --> 00:02:42,125 So when we switch to the AI later 50 00:02:42,125 --> 00:02:44,625 we only need to create two variables 51 00:02:44,625 --> 00:02:46,850 The first is Equip 52 00:02:46,850 --> 00:02:53,075 This boolean tells our AI whether the sword is equipped or not 53 00:02:53,075 --> 00:02:55,900 The other is Defense 54 00:02:55,900 --> 00:02:58,525 Because our AI also needs defense 55 00:02:58,725 --> 00:03:01,725 OK, let's switch to our browser 56 00:03:01,725 --> 00:03:05,525 Then let's copy 57 00:03:05,525 --> 00:03:07,825 Click on the Copy here 58 00:03:07,825 --> 00:03:10,550 Certainly, we can't follow the previous name 59 00:03:10,550 --> 00:03:14,550 Let's name it as BPA_NegativeAI 60 00:03:14,550 --> 00:03:19,150 Let's move this to the AI folder 61 00:03:19,150 --> 00:03:22,150 If you don't have these in the left 62 00:03:22,150 --> 00:03:24,325 You can click this switch here 63 00:03:24,325 --> 00:03:27,425 Then move it into this AI 64 00:03:27,425 --> 00:03:30,950 Then open the AI folder and find this 65 00:03:31,231 --> 00:03:39,050 We can delete these because they read from the player 66 00:03:39,050 --> 00:03:43,100 Now this blueprint is to be used on AI 67 00:03:43,100 --> 00:03:46,425 so we can no longer call variables from the player 68 00:03:46,425 --> 00:03:48,875 We need to call variables from the AI itself 69 00:03:48,875 --> 00:03:50,775 cast to bp 70 00:03:50,775 --> 00:03:53,375 Select this NegativeAI 71 00:03:53,375 --> 00:03:57,400 Let's put it here and then connect it to here 72 00:03:57,450 --> 00:04:00,350 OK. Then organize them 73 00:04:00,350 --> 00:04:04,775 Then get equip 74 00:04:04,775 --> 00:04:07,800 Then get defense 75 00:04:07,800 --> 00:04:10,000 Get these two 76 00:04:10,000 --> 00:04:12,525 OK, it's almost done 77 00:04:12,525 --> 00:04:18,350 Let's put this Reset Attack Montage aside 78 00:04:18,350 --> 00:04:19,500 OK 79 00:04:19,500 --> 00:04:21,975 Then let's go back to the AI 80 00:04:21,975 --> 00:04:25,550 Then apply the Animation Blueprint we created for it 81 00:04:25,775 --> 00:04:29,350 We have named it BPA_NegativeAI 82 00:04:29,350 --> 00:04:30,575 Let's go back 83 00:04:30,575 --> 00:04:35,350 Now you can find that our AI can turn towards our player 84 00:04:35,350 --> 00:04:41,625 and its static animation has also been done 85 00:04:41,625 --> 00:04:44,180 Now we need to implement another function 86 00:04:44,205 --> 00:04:50,125 That is to use a Blueprint Interface to communicate with AI 87 00:04:50,125 --> 00:04:51,670 Tell the AI that 88 00:04:51,694 --> 00:04:55,050 we are ready to fight 89 00:04:55,050 --> 00:04:57,750 Now let's go back to the Content Browser 90 00:04:57,750 --> 00:05:00,050 Let's create a new folder here 91 00:05:00,050 --> 00:05:05,000 Name it BP_WorldSetting 92 00:05:05,025 --> 00:05:10,250 Put all relevant blueprints in here 93 00:05:10,275 --> 00:05:12,000 We may use it less frequent 94 00:05:12,000 --> 00:05:14,825 Let's put the Blueprint Interface into it first 95 00:05:14,825 --> 00:05:17,400 It's not created from the Blueprint Class here 96 00:05:17,400 --> 00:05:21,925 We can find it in the Blueprints under Create Advanced Asset 97 00:05:21,925 --> 00:05:23,525 Find Blueprint Interface 98 00:05:23,525 --> 00:05:26,375 Name it with the BPI prefix 99 00:05:26,375 --> 00:05:30,225 It's the abbreviation of Blueprint Interface 100 00:05:30,225 --> 00:05:33,725 So I like to name it with the BPI prefix 101 00:05:33,725 --> 00:05:36,975 Please remember this prefix, it's very important 102 00:05:36,975 --> 00:05:40,525 because there are hundreds types of blueprint interfaces 103 00:05:40,525 --> 00:05:44,625 With this prefix, we can find it directly 104 00:05:44,625 --> 00:05:48,100 Let's name it ReadyToFight 105 00:05:49,300 --> 00:05:53,700 After we open it, we can see a new function here 106 00:05:53,700 --> 00:05:57,575 This new function is the event we call 107 00:05:57,575 --> 00:05:59,925 Let's name it Ready 108 00:05:59,925 --> 00:06:00,925 OK 109 00:06:01,000 --> 00:06:03,775 Then let's compile 110 00:06:03,775 --> 00:06:10,100 OK. Then let's focus on the player 111 00:06:10,100 --> 00:06:14,300 Then how to use the Blueprint Interface we created on the player 112 00:06:14,300 --> 00:06:18,675 First, click on the Class Setup here 113 00:06:18,675 --> 00:06:22,725 In it, we can change the Parent Class 114 00:06:22,725 --> 00:06:26,050 And customize these blueprint options 115 00:06:26,050 --> 00:06:28,875 We need to find the interface 116 00:06:28,875 --> 00:06:32,475 Then you can find that there is zero implemented interface 117 00:06:32,475 --> 00:06:34,450 Click the Add here 118 00:06:34,450 --> 00:06:39,525 Here are actually 49 options to select from 119 00:06:39,525 --> 00:06:43,475 Search for bpi, the prefix we used in here 120 00:06:43,475 --> 00:06:46,205 Select this Ready to Fight. Then it's added directly 121 00:06:46,525 --> 00:06:47,875 OK 122 00:06:47,875 --> 00:06:53,100 Let's compile it again 123 00:06:53,100 --> 00:06:55,689 Use this Blueprint Interface 124 00:06:55,713 --> 00:06:57,500 when the player drawing the sword 125 00:06:57,500 --> 00:06:59,425 Go back to the Equip here 126 00:06:59,875 --> 00:07:02,725 After the player drawing the sword 127 00:07:02,725 --> 00:07:04,650 we're going to make a call here 128 00:07:04,650 --> 00:07:08,475 Enter bpi and close the Context Sensitive 129 00:07:08,475 --> 00:07:13,850 It is suffixed by Message when we conveying message 130 00:07:13,950 --> 00:07:21,250 The Target is what we want to convey the message to 131 00:07:21,250 --> 00:07:29,275 Get the AI variable that we have instanced and put it here 132 00:07:29,275 --> 00:07:32,850 It's like telling it that we're ready 133 00:07:32,850 --> 00:07:37,100 Let's go back to the AI, it has Class Setup option 134 00:07:37,375 --> 00:07:41,050 Just like the character 135 00:07:41,050 --> 00:07:44,350 we need to add blueprint interface 136 00:07:44,350 --> 00:07:48,825 Add BPI Ready to Fight 137 00:07:48,825 --> 00:07:49,967 OK 138 00:07:50,150 --> 00:07:55,275 Then how to receive the message from the player 139 00:07:55,275 --> 00:07:59,675 Search ready to fight here 140 00:07:59,825 --> 00:08:03,625 Add an Event Ready 141 00:08:03,625 --> 00:08:08,350 to receive the message from the player 142 00:08:08,425 --> 00:08:11,850 Then tick this 143 00:08:11,850 --> 00:08:15,725 then enter montage 144 00:08:15,725 --> 00:08:18,250 Turn off Context Sensitive 145 00:08:19,194 --> 00:08:21,325 Here is Montage Play 146 00:08:21,780 --> 00:08:28,650 Then Get Anim Instance, Mesh 147 00:08:28,675 --> 00:08:31,600 As for the Asset, let's go back to the base role 148 00:08:31,600 --> 00:08:37,675 AI and player has the same sword-drawing animation 149 00:08:37,675 --> 00:08:40,675 Let's get it and apply it on the AI 150 00:08:40,675 --> 00:08:44,050 OK, the basic function is done 151 00:08:44,050 --> 00:08:45,650 Let's compile it 152 00:08:45,650 --> 00:08:50,450 After the player drawing the sword, the AI also draws the sword 153 00:08:50,450 --> 00:08:52,600 But the AI draws rather slow 154 00:08:52,600 --> 00:08:57,350 Go back to the player and add a Sequence here 155 00:08:57,350 --> 00:09:01,100 Let it delay about 1 second 156 00:09:01,100 --> 00:09:03,325 and then tell AI to draw the sword 157 00:09:03,325 --> 00:09:05,050 Otherwise 2.5 seconds is a bit slow 158 00:09:05,050 --> 00:09:07,125 Let's add a Delay. OK 159 00:09:07,125 --> 00:09:15,725 Place these boolean value in front 160 00:09:15,725 --> 00:09:18,000 and keep these ones here 161 00:09:18,050 --> 00:09:19,450 Now let's have a try 162 00:09:20,400 --> 00:09:22,675 OK, see, it moves faster 163 00:09:22,850 --> 00:09:25,475 Now it's ready to fight 164 00:09:25,475 --> 00:09:26,550 OK 165 00:09:26,550 --> 00:09:29,175 Then what we need to realize is 166 00:09:29,175 --> 00:09:32,650 for example, after the player drawing the sword 167 00:09:32,675 --> 00:09:35,225 the AI will get ready to fight 168 00:09:35,225 --> 00:09:38,525 the AI will start to follow our player 169 00:09:38,525 --> 00:09:41,200 OK, let's start to produce 170 00:09:41,200 --> 00:09:47,300 Let's return to the AI Behavior Tree 171 00:09:47,300 --> 00:09:50,300 Turn off those redundant projects 172 00:09:50,600 --> 00:09:52,900 Let's return to our AI behavior tree 173 00:09:52,900 --> 00:09:55,000 It's here 174 00:09:55,300 --> 00:09:59,075 We need to create a new bool key named ReadyToFight 175 00:09:59,075 --> 00:10:05,100 I think you should know, as we have covered in previous lessons 176 00:10:05,100 --> 00:10:08,925 that our AI Behavior Tree cannot read 177 00:10:08,925 --> 00:10:11,875 the values in the character's blueprint 178 00:10:11,875 --> 00:10:14,225 But the values in our character's blueprint can set 179 00:10:14,225 --> 00:10:17,200 the values of Blackboard in Behavior Tree 180 00:10:17,225 --> 00:10:18,625 You should know this 181 00:10:18,625 --> 00:10:21,917 And the AI Behavior Tree can only call the values in Blackboard 182 00:10:21,942 --> 00:10:23,850 OK, now let's return to our AI 183 00:10:23,850 --> 00:10:26,775 We need to read the blackboard here 184 00:10:26,775 --> 00:10:28,700 Similar to this 185 00:10:28,700 --> 00:10:31,075 Get Blackboard 186 00:10:31,075 --> 00:10:38,913 and then set the blackboard value as bool 187 00:10:39,248 --> 00:10:41,018 Link bool with Montage Play 188 00:10:41,725 --> 00:10:44,825 Then tick Bool Value 189 00:10:44,825 --> 00:10:47,500 Then Create Literal Name 190 00:10:47,500 --> 00:10:49,450 Name it as ReadyToFight 191 00:10:49,450 --> 00:10:51,600 OK. Then 192 00:10:53,725 --> 00:10:56,275 OK, finished 193 00:10:56,275 --> 00:10:58,375 Then when this bool value is ticked 194 00:10:58,375 --> 00:11:01,600 The AI will be told to fight 195 00:11:01,600 --> 00:11:03,925 Then let's go back to the AI Behavior Tree 196 00:11:04,059 --> 00:11:12,350 Here let's put these two in one event 197 00:11:12,350 --> 00:11:16,525 Then let's create a new Sequence here 198 00:11:16,525 --> 00:11:20,975 As I told you before, the function of Selector is 199 00:11:20,975 --> 00:11:23,711 if the first one is selected, the second one won't 200 00:11:23,736 --> 00:11:25,700 and vice versa 201 00:11:25,775 --> 00:11:27,875 Now it's like choosing one from two 202 00:11:27,875 --> 00:11:30,925 Judge whether the first thing can be executed 203 00:11:30,925 --> 00:11:37,500 If it can be executed, then the second won't be executed 204 00:11:37,500 --> 00:11:40,675 Execute the second when the first can't be executed 205 00:11:40,675 --> 00:11:44,500 Then Add Decorator on this Composite Node 206 00:11:44,500 --> 00:11:48,150 I may have said it before the last lesson 207 00:11:48,150 --> 00:11:51,350 that the Decorator is used to judge the values 208 00:11:51,350 --> 00:11:54,800 Then let's get the value of ReadyToFight first 209 00:11:54,800 --> 00:11:58,975 If this value is true, we execute the following 210 00:11:58,975 --> 00:12:02,200 If this value is false, we execute the stuff here 211 00:12:02,200 --> 00:12:04,925 Here we can name it Focus 212 00:12:05,625 --> 00:12:06,825 OK 213 00:12:07,625 --> 00:12:12,125 These two are completely independent events 214 00:12:12,125 --> 00:12:19,075 If this is true, the AI starts to move to our character 215 00:12:19,075 --> 00:12:20,825 Use Move To 216 00:12:20,825 --> 00:12:28,725 As for Move To, we may choose not only vectors 217 00:12:28,725 --> 00:12:31,425 but also blueprints 218 00:12:31,425 --> 00:12:35,150 We can directly select the corresponding blueprint to move to 219 00:12:35,150 --> 00:12:36,336 But as you can see 220 00:12:36,360 --> 00:12:39,925 we can't select the Target we created from here 221 00:12:39,925 --> 00:12:42,074 So we need to return to the Blackboard 222 00:12:42,099 --> 00:12:44,250 Turn on the Key Type in Target 223 00:12:44,250 --> 00:12:48,900 And the base class should be Actor 224 00:12:48,975 --> 00:12:53,750 OK, now we can select the Target here 225 00:12:53,750 --> 00:12:56,250 OK, now let's try it 226 00:12:57,150 --> 00:12:59,775 The player draws the sword 227 00:13:01,550 --> 00:13:04,325 Now the AI starts to move 228 00:13:04,325 --> 00:13:08,600 But it moves so fast 229 00:13:08,600 --> 00:13:10,800 A bit too fast, we can modify it here 230 00:13:10,900 --> 00:13:12,950 Set Max Walk Speed 231 00:13:12,950 --> 00:13:16,300 Let's set it to 150 232 00:13:16,300 --> 00:13:21,475 Then let's delay the play 233 00:13:21,475 --> 00:13:23,700 Let's see how many seconds to set 234 00:13:24,925 --> 00:13:27,925 It's duration is 2.6 235 00:13:27,925 --> 00:13:31,975 Actually, I think 2 seconds is OK 236 00:13:31,975 --> 00:13:33,725 Let's set it to 2 237 00:13:34,350 --> 00:13:38,850 We have set the Max Walk Speed to 150 238 00:13:38,850 --> 00:13:40,575 Let's set it to 125 239 00:13:40,575 --> 00:13:43,575 No, set it to 150, since its body is big 240 00:13:43,575 --> 00:13:45,100 Let's try again 241 00:13:45,100 --> 00:13:46,225 OK 242 00:13:46,225 --> 00:13:48,000 The player draws the sword 243 00:13:48,000 --> 00:13:49,500 Then the AI 244 00:13:49,500 --> 00:13:50,875 Why it doesn't move 245 00:13:50,875 --> 00:13:52,250 OK, now it moves 246 00:13:52,250 --> 00:13:55,625 But now it walks slower than before 247 00:13:55,625 --> 00:13:57,185 Then you will find it doesn't move 248 00:13:57,209 --> 00:13:58,725 after reaching to a certain place 249 00:13:58,725 --> 00:14:00,250 That is a problem 250 00:14:00,250 --> 00:14:01,700 Let's return to here 251 00:14:01,700 --> 00:14:04,100 We didn't enlarge it before 252 00:14:04,100 --> 00:14:07,850 Now we need to scale up the Nav mesh 253 00:14:07,850 --> 00:14:14,250 Let's enlarge it so that to cover the entire map 254 00:14:14,467 --> 00:14:15,842 Place it here 255 00:14:18,075 --> 00:14:19,975 Move it to the center 256 00:14:20,400 --> 00:14:22,700 Enlarge it to cover the entire map 257 00:14:22,700 --> 00:14:24,425 Now let's try it again 258 00:14:25,675 --> 00:14:26,725 OK 259 00:14:26,900 --> 00:14:31,775 OK, now the AI follows the player to move 260 00:14:32,275 --> 00:14:36,050 OK, we have completed this function in this lesson 261 00:14:36,050 --> 00:14:38,450 In the next lesson, we will create this 262 00:14:38,450 --> 00:14:44,325 when the AI moves near the player, it attacks and rolls 263 00:14:44,325 --> 00:14:46,325 Just like the player 264 00:14:46,325 --> 00:14:50,325 it can attack and defend 265 00:14:50,325 --> 00:14:52,975 So in the next lesson we will mainly introduce 266 00:14:52,975 --> 00:14:55,775 the attacks and rolls of the AI 267 00:14:55,775 --> 00:14:58,875 OK, so that's all for this lesson 268 00:14:58,875 --> 00:15:00,825 OK, see you in the next lesson