1 00:00:00,000 --> 00:00:05,240 ♪♪♪ 2 00:00:05,240 --> 00:00:06,990 Zak Parrish: All right, we are back. 3 00:00:06,990 --> 00:00:11,840 We are ready to start building some of the actual gameplay in our game. 4 00:00:11,840 --> 00:00:16,960 We will begin by creating an Enemy Character that we can interact with. 5 00:00:16,960 --> 00:00:22,180 In the Content Browser under C++Classes, open the TwinStickShooter folder. 6 00:00:22,180 --> 00:00:25,030 Here is our BaseCharacter C++ class. 7 00:00:25,030 --> 00:00:27,900 Right-click on the BaseCharacter and 8 00:00:27,900 --> 00:00:33,960 select Create Blueprint class based on BaseCharacter. 9 00:00:33,960 --> 00:00:38,590 Call this class "EnemyCharacter". 10 00:00:38,590 --> 00:00:41,140 These are such creative names, right? 11 00:00:41,140 --> 00:00:44,690 For Path, select the Blueprints folder. 12 00:00:44,690 --> 00:00:46,390 Click the Create Blueprint Class button. 13 00:00:46,390 --> 00:00:49,640 Wait a second, and it magically appears. 14 00:00:49,640 --> 00:00:52,370 Dock this window at the top and adjust the panels 15 00:00:52,370 --> 00:00:56,100 so we can see all the different bits and pieces again. 16 00:00:56,100 --> 00:00:59,590 We have some of the same things to do as we did with the Hero Character. 17 00:00:59,590 --> 00:01:01,120 Select the Mesh Component. In the Details panel, 18 00:01:01,120 --> 00:01:04,900 click the Mesh drop down menu and select SK_Mannequin (Skeletal Mesh). 19 00:01:04,900 --> 00:01:08,820 Place the Skeletal Mesh inside the capsule just like before. 20 00:01:08,820 --> 00:01:13,300 Press E to rotate the mesh 90° so it is facing forward. 21 00:01:13,300 --> 00:01:17,640 Now, I don't want the enemies to be the same color as the hero. 22 00:01:17,640 --> 00:01:21,870 That is going to be be confusing and too much to look at. 23 00:01:21,870 --> 00:01:24,450 Let's figure out how we can change the color. 24 00:01:24,450 --> 00:01:27,390 In the Details panel, Double-click to open the Skeletal Mesh. 25 00:01:27,390 --> 00:01:33,290 This opens the Skeletal Mesh on the Mesh tab in Persona. 26 00:01:33,290 --> 00:01:36,710 We can pan around, and see how awesome this character looks. 27 00:01:36,710 --> 00:01:42,490 He does look pretty cool, but we can also see the materials applied to him. 28 00:01:42,490 --> 00:01:47,920 There are two (2) materials: M_UE4Man_Body and UE4Man_Chest_Logo. 29 00:01:47,920 --> 00:01:54,450 The M_UE4Man_Chest_Logo should be an instance of M_UE4Man_Body. 30 00:01:54,450 --> 00:02:02,440 Double-click to open M_UE4Man_Body in the Material Editor. 31 00:02:02,440 --> 00:02:05,160 There is not that much going on here. 32 00:02:05,160 --> 00:02:08,600 It is really just blending together a few layered materials. 33 00:02:08,600 --> 00:02:13,170 You have some areas that look like metal, dark grey plastic, and then this beige 34 00:02:13,170 --> 00:02:16,460 plastic which sort of dominates the whole character. 35 00:02:16,460 --> 00:02:22,420 That beige color is a parameter named BodyColor. 36 00:02:22,420 --> 00:02:25,340 If we make a dynamic version of this material and change BodyColor, 37 00:02:25,340 --> 00:02:30,330 we can thereby change the color of the entire character. 38 00:02:30,330 --> 00:02:33,810 Note the spelling, it is BodyColor without a space. 39 00:02:33,810 --> 00:02:36,380 I am going to select BodyColor inside the Details panel 40 00:02:36,380 --> 00:02:41,500 and press Ctrl + C to Copy, so I don't have to type the name later. 41 00:02:41,500 --> 00:02:45,630 Go back to EnemyCharacter and go to the Construction Script. 42 00:02:45,630 --> 00:02:52,030 Drag-and-drop the Mesh Component into the script to create a reference to it. 43 00:02:52,030 --> 00:02:53,790 Drag a wire off Mesh. 44 00:02:53,790 --> 00:02:59,750 We need a dynamic version of the material that is applied to Index 0. 45 00:02:59,750 --> 00:03:03,530 How do I know the material is at Index 0? Go to EnemyCharacter. 46 00:03:03,530 --> 00:03:06,400 In the Mesh Details panel, we have Element 0 and Element 1. 47 00:03:06,400 --> 00:03:09,750 Element 0 is the main material. Element 1 is the chest logo, 48 00:03:09,750 --> 00:03:16,160 which is just giving us the little UE4 logo you see here. 49 00:03:16,160 --> 00:03:19,500 I can zoom right up on the logo. 50 00:03:19,500 --> 00:03:21,780 Go back to EnemyCharacter. 51 00:03:21,780 --> 00:03:29,810 Drag a wire off Mesh and type "dynamic". 52 00:03:29,810 --> 00:03:32,910 Select Create Material Dynamic Instance. 53 00:03:32,910 --> 00:03:36,660 This is a kind of a do it all at once node. I love this node. 54 00:03:36,660 --> 00:03:40,590 This node is grabbing whatever material found in Element Index 0, 55 00:03:40,590 --> 00:03:44,450 and it is converting it to a dynamic version 56 00:03:44,450 --> 00:03:48,050 so you can change any parameters found inside of it. 57 00:03:48,050 --> 00:03:53,980 Once it has done that, it reapplies it back to the same Element number. 58 00:03:53,980 --> 00:03:57,090 Connect the Construction Script to the Create Dynamic Material Instance. 59 00:03:57,090 --> 00:04:00,780 Let's set this to a value. 60 00:04:00,780 --> 00:04:03,989 I am not saying we will ever use it, but let's do it anyway. 61 00:04:03,989 --> 00:04:07,740 Right-click the Return Value and select Promote to Variable. 62 00:04:07,740 --> 00:04:10,180 Name this variable "DynaMat". 63 00:04:10,180 --> 00:04:13,610 64 00:04:13,610 --> 00:04:16,420 Drag a wire off the Return Value of the 65 00:04:16,420 --> 00:04:21,250 Dyna Mat variable, type "set vector" 66 00:04:21,250 --> 00:04:24,320 and select Set Vector Parameter Value. 67 00:04:24,320 --> 00:04:26,030 68 00:04:26,030 --> 00:04:30,310 This node asks for the Parameter Name you want to talk to. 69 00:04:30,310 --> 00:04:32,610 Remember from earlier, we copied BodyColor. 70 00:04:32,610 --> 00:04:37,650 Press Ctrl + V to Paste BodyColor into Parameter Name. 71 00:04:37,650 --> 00:04:39,690 What color are we going to set it to? Click Value to open the Color Picker. 72 00:04:39,690 --> 00:04:42,880 This is where you decide what color you want your Enemy to be. 73 00:04:42,880 --> 00:04:45,880 Let's choose some shade of red. 74 00:04:45,880 --> 00:04:50,930 Let's choose a bright red. There you go. 75 00:04:50,930 --> 00:04:52,390 It just screams danger. 76 00:04:52,390 --> 00:04:58,410 Go to the Construction Script and click Compile. Go to the Viewport tab. 77 00:04:58,410 --> 00:05:02,280 The character is bright red, which is pretty cool. Go to the Construction Script. 78 00:05:02,280 --> 00:05:07,740 Right-click on the Value pin and select Promote to Variable. 79 00:05:07,740 --> 00:05:15,150 Call this variable "EnemyColor". 80 00:05:15,150 --> 00:05:16,410 Go to the Viewport tab. 81 00:05:16,410 --> 00:05:18,410 In the My Blueprint panel, select EnemyColor. 82 00:05:18,410 --> 00:05:20,300 Click Compile. Go to the Details panel under Default Value, 83 00:05:20,300 --> 00:05:25,010 Double-click Enemy Color to open the Color Picker, and set this to any shade you want. 84 00:05:25,010 --> 00:05:26,580 Your enemy can be anything. 85 00:05:26,580 --> 00:05:28,720 He could be bright yellow. 86 00:05:28,720 --> 00:05:30,360 Or, he could be orange. 87 00:05:30,360 --> 00:05:33,280 I am going to set him back to red, and we will leave that setting. 88 00:05:33,280 --> 00:05:37,460 I will desaturate the color just a little bit. There we go. 89 00:05:37,460 --> 00:05:39,430 That looks very dangerous. You will notice 90 00:05:39,430 --> 00:05:42,820 this does not change the color of the logo. That is fine. 91 00:05:42,820 --> 00:05:47,470 We will leave it as a nice little beige logo on his chest. 92 00:05:47,470 --> 00:05:53,870 Now, we have a nice visual differentiation between our Hero and our Enemy. 93 00:05:53,870 --> 00:05:59,050 That should make it easier to tell them apart on the screen, which is great. 94 00:05:59,050 --> 00:06:07,970 With that done, let's set up the AIController that is going to drive this Enemy around. 95 00:06:07,970 --> 00:06:11,100 I am only doing this because we are only about 6 minutes into this video. 96 00:06:11,100 --> 00:06:14,440 It is such a simple concept that I didn't want to put it in 97 00:06:14,440 --> 00:06:18,030 its own video because it would be very, very short. 98 00:06:18,030 --> 00:06:23,120 Go to the Content Browser and select the Blueprints folder to set this up. 99 00:06:23,120 --> 00:06:28,300 Right-click inside the Blueprints folder and select Blueprint Class. 100 00:06:28,300 --> 00:06:31,200 We want to base this class off AIController, 101 00:06:31,200 --> 00:06:35,650 which does not appear in our Pick Parent Class list. To find AIController, 102 00:06:35,650 --> 00:06:45,220 expand All Classes, type and select "AIController". 103 00:06:45,220 --> 00:06:48,190 Click the green Select button. 104 00:06:48,190 --> 00:06:52,790 Name this class EnemyAI. 105 00:06:52,790 --> 00:06:54,320 Double-click to open EnemyAI. 106 00:06:54,320 --> 00:06:57,130 This Blueprint is like any other Blueprint. 107 00:06:57,130 --> 00:07:00,630 It has all of the same panels. I will put back the panels back like they were. 108 00:07:00,630 --> 00:07:01,730 Go to the Event Graph. 109 00:07:01,730 --> 00:07:04,910 The AIController has some components to help it do some things. 110 00:07:04,910 --> 00:07:06,850 It has a TransformComponent. 111 00:07:06,850 --> 00:07:10,820 It has a PathFollowingComponent, which will make use of a Nav Mesh. 112 00:07:10,820 --> 00:07:13,590 It also has an ActionsComp or Actions Component, 113 00:07:13,590 --> 00:07:17,930 which is going to be used for various AI behaviors. 114 00:07:17,930 --> 00:07:23,389 As I mentioned, this is going to be a very, very simple AIController. 115 00:07:23,389 --> 00:07:30,330 Right-click in the graph, type and select "Custom Event". 116 00:07:30,330 --> 00:07:34,790 Call this event "TrackPlayer". 117 00:07:34,790 --> 00:07:35,960 That is all it is going to do. 118 00:07:35,960 --> 00:07:39,340 You could call the event ChasePlayer, TrackPlayer, HuntPlayer, or whatever. 119 00:07:39,340 --> 00:07:41,190 It is going to do the same thing. 120 00:07:41,190 --> 00:07:44,020 It is going to do a special function. Drag off TrackPlayer, 121 00:07:44,020 --> 00:07:47,530 type and select "AI Move To". 122 00:07:47,530 --> 00:07:49,780 The AI Move To node takes a Pawn 123 00:07:49,780 --> 00:07:53,050 and tells it to move toward a destination, or toward a 124 00:07:53,050 --> 00:07:57,160 Target Actor. Once it gets to a within the acceptance radius, it stops. 125 00:07:57,160 --> 00:07:59,880 The nice thing about the AI Move To node is 126 00:07:59,880 --> 00:08:02,500 it will keep moving the Pawn toward that target 127 00:08:02,500 --> 00:08:05,100 Actor until it hits the acceptance radius. 128 00:08:05,100 --> 00:08:07,769 This means we don't have to call this AI Move To node very often 129 00:08:07,769 --> 00:08:12,060 in order to have something chase our player pretty much all the time. 130 00:08:12,060 --> 00:08:14,600 We need to assign the Move To node the Pawn that is being driven, 131 00:08:14,600 --> 00:08:16,610 and we need to assign a Target. 132 00:08:16,610 --> 00:08:19,010 The Pawn that is being driven is easy to assign. 133 00:08:19,010 --> 00:08:23,340 Since this is the AIController, this Controller will be plugged 134 00:08:23,340 --> 00:08:27,840 into the side of our Enemy Character's head like a cartridge. 135 00:08:27,840 --> 00:08:30,500 That is a metaphor. That is not how it is really going to be. There is no cartridge 136 00:08:30,500 --> 00:08:32,900 hanging off the side of its head. Go with me. 137 00:08:32,900 --> 00:08:37,530 Right-click in the graph, type and select "Get Controlled Pawn". 138 00:08:37,530 --> 00:08:40,320 The Get Controlled Pawn node is literally a reference to the Pawn 139 00:08:40,320 --> 00:08:43,110 controlled by this AIController. 140 00:08:43,110 --> 00:08:47,460 141 00:08:47,460 --> 00:08:49,190 Next, we need the Target Actor. 142 00:08:49,190 --> 00:08:54,900 Right-click in the graph, type and select "Get Player Character". 143 00:08:54,900 --> 00:08:57,480 There it is. We get the Player Character. 144 00:08:57,480 --> 00:08:59,400 Plug the Return Value into Target Actor. The Player Character becomes the Target Actor. 145 00:08:59,400 --> 00:09:00,770 That is all we need to do. 146 00:09:00,770 --> 00:09:02,550 We just need to use the Get Player Character node. 147 00:09:02,550 --> 00:09:05,610 Now when TrackPlayer is called, the Enemy will just 148 00:09:05,610 --> 00:09:09,200 move toward the Hero until it gets within 5 units. 149 00:09:09,200 --> 00:09:11,550 A value of 5 units is fine; we don't need to change that. 150 00:09:11,550 --> 00:09:14,370 However, we do need to have something that 151 00:09:14,370 --> 00:09:17,370 keeps calling TrackPlayer over and over. 152 00:09:17,370 --> 00:09:20,920 We want something to keep pinging to keep tracking the player 153 00:09:20,920 --> 00:09:22,800 because if the Enemy ever gets within this radius, 154 00:09:22,800 --> 00:09:25,520 the AI Move To node will stop firing. 155 00:09:25,520 --> 00:09:29,980 The Enemy will never chase the player again if we don't explicitly tell him to. 156 00:09:29,980 --> 00:09:35,790 To do that, we are going to set a timer. Right-click, type and select "Set Timer". 157 00:09:35,790 --> 00:09:40,700 A timer in UE4 is just like a camera timer; there will be a countdown. 158 00:09:40,700 --> 00:09:44,290 At the end of the countdown, the timer will call some function. 159 00:09:44,290 --> 00:09:47,020 Type the name of the function inside Function Name. 160 00:09:47,020 --> 00:09:51,710 Set Function Name to "TrackPlayer". 161 00:09:51,710 --> 00:09:53,500 How often do we want to track it? 162 00:09:53,500 --> 00:09:56,130 Set Time to 1.0 second. 163 00:09:56,130 --> 00:10:00,680 Check the Looping checkbox; it will call TrackPlayer every second. 164 00:10:00,680 --> 00:10:02,320 Notice, Set Timer is not an event. 165 00:10:02,320 --> 00:10:08,470 We need something that will plug into the executable pin and call this node. 166 00:10:08,470 --> 00:10:11,450 Drag the Event BeginPlay node over and plug it into the Set Timer node. 167 00:10:11,450 --> 00:10:16,940 This means the moment this AI character spawns, or the moment the game begins, 168 00:10:16,940 --> 00:10:19,340 this Set Timer will be called. 169 00:10:19,340 --> 00:10:22,050 Set Timer is going to keep calling TrackPlayer once per second 170 00:10:22,050 --> 00:10:27,050 and keep telling the AI to chase the Player, over and over. 171 00:10:27,050 --> 00:10:29,600 Click Compile and click Save. 172 00:10:29,600 --> 00:10:33,010 Then, go to the EnemyCharacter tab. We are going to set up a few things. 173 00:10:33,010 --> 00:10:36,480 Click the Class Defaults button. 174 00:10:36,480 --> 00:10:41,500 In the Details panel under Pawn, click the AIController Class property 175 00:10:41,500 --> 00:10:45,000 drop down menu and select EnemyAI. 176 00:10:45,000 --> 00:10:47,120 Click Compile and click Save. 177 00:10:47,120 --> 00:10:53,680 Now, watch this. Drag-and-drop EnemyCharacter into the world and click Play. 178 00:10:53,680 --> 00:10:55,010 Nothing is going to happen yet. 179 00:10:55,010 --> 00:10:58,800 Let's just move over to the enemy. He is just sitting here being boring. 180 00:10:58,800 --> 00:11:00,340 His behavior is actually there. 181 00:11:00,340 --> 00:11:05,350 He has the requisite logic to make him move around. 182 00:11:05,350 --> 00:11:09,280 He doesn't have a Navigation Mesh yet. 183 00:11:09,280 --> 00:11:11,690 Navigation Meshes are very easy to do in UE4. 184 00:11:11,690 --> 00:11:17,360 Watch this. In the Modes panel, select the Volumes category. 185 00:11:17,360 --> 00:11:20,840 You should see Nav Mesh Bounds Volume. 186 00:11:20,840 --> 00:11:22,520 Drag-and-drop Nav Mesh Bounds Volume onto your floor. 187 00:11:22,520 --> 00:11:27,450 Move the Nav Mesh Bounds Volume down because it needs to penetrate into your floor. 188 00:11:27,450 --> 00:11:29,080 Press R to use the Scale tool and scale 189 00:11:29,080 --> 00:11:33,550 the volume so it completely covers the floor. 190 00:11:33,550 --> 00:11:36,390 Press the P key to visualize your Nav Mesh. 191 00:11:36,390 --> 00:11:37,570 There you go. 192 00:11:37,570 --> 00:11:40,010 There is your Navigation Mesh. It is already done. 193 00:11:40,010 --> 00:11:44,250 Again, it is very, very easy. Click Play. 194 00:11:44,250 --> 00:11:48,170 Oh my goodness, he is so fast! We can't get away from him! 195 00:11:48,170 --> 00:11:50,200 That is actually kind of ridiculous. 196 00:11:50,200 --> 00:11:51,750 We need to slow him down. 197 00:11:51,750 --> 00:11:53,830 Click Pause to stop playing. 198 00:11:53,830 --> 00:11:56,330 In the Content Browser, Double-click to open the EnemyCharacter. 199 00:11:56,330 --> 00:12:00,960 In the Components panel, select the CharacterMovementComponent. 200 00:12:00,960 --> 00:12:02,330 In the Details panel under Character Movement: Walking, 201 00:12:02,330 --> 00:12:10,180 set the Max Walk Speed to 200. 202 00:12:10,180 --> 00:12:12,960 That will probably make the game too easy, but you can always tweak the value later. 203 00:12:12,960 --> 00:12:17,470 Click Compile and click Save. Go to ArenaMap and click Play. 204 00:12:17,470 --> 00:12:19,190 There you go. The enemy is chasing us, 205 00:12:19,190 --> 00:12:22,579 and he will keep chasing us over and over. 206 00:12:22,579 --> 00:12:24,240 If he touches us, he will wait a second 207 00:12:24,240 --> 00:12:27,510 and then he will start chasing again. 208 00:12:27,510 --> 00:12:28,570 There you go. 209 00:12:28,570 --> 00:12:31,940 We have an enemy with his own AI that is just 210 00:12:31,940 --> 00:12:35,160 chasing the Player, which is pretty awesome. 211 00:12:35,160 --> 00:12:37,120 Press Pause. 212 00:12:37,120 --> 00:12:40,240 That is going to wrap things up for this video. 213 00:12:40,240 --> 00:12:40,940 Thanks a lot. 214 00:12:40,940 --> 00:12:49,603 ♪♪♪