Original subtitles

0 Welcome to the main player functionality. 1

In this video we will dive deep into the player and how its main functionalities actually work. Here, 2

in the main scene there is the player instance, but the player is actually a scene in itself, so we're 3

going to head right into it. 4

What are the main functionalities of the player? 5

And this is important. 6

If I quickly play this. 7

You'll see that the player can rotate the turret. 8

It can move. 9

With W, 10

A 11

S 12

D 13

And also the arrow keys. 14

And also it can fire. 15

The turret will move to a specific position where the cursor is pointed at. 16

And if you press the leftmost button, the tank will fire. 17

Basically these are the main functionalities of the player. 18

There are a couple of hidden ones, for example, the turret animation. 19

As you can see, the turret slightly moves back and also the tank body slightly moves back. 20

And if I aim in the other direction, you see that it moves in the other direction. 21

So this is also in place. 22

This is basically a game polish thing. 23

It's not a functionality. 24

But we will also cover this in this episode. 25

Okay, so let's deep dive. 26

The player, as I mentioned, is a self-contained scene. Inside of it 27

there are two main parts, the dynamic one or the moving one and the static one. 28

And basically the moving one is the actual player mesh and the collision and things that the player 29

actually moves when they press the keys. 30

The systems part or the static one is the part that actually stays in place all the time. 31

I took this decision because in some cases, some systems and some functionalities do require a fixed 32

position in the scene, and instead of taking it out from the player, it's better to have it self-contained 33

because they're in fact functionalities of the player. 34

But we'll get into that a little later. 35

As I mentioned, the player body is the moving part. 36

What does it contain? 37

Of course it has the player camera. 38

And the camera is what actually makes the player visible. 39

But in this scene, we have two cameras that you can cycle through. 40

If I play it again and press [C] we have this big camera, which is actually a scene camera, 41

and this is the player camera. 42

This is your experience as the player camera. 43

This camera moves the the player. The movement is done automatically because the camera is a child 44

to the player. 45

So that's easily fixed. 46

Next we have the 3D mesh of the player. 47

This is basically the 3D models that make the player up. 48

We also have the collision shape, which is a box shape in this case. 49

This handles the projectile collisions with the player, but also the collisions with the building. 50

So we don't let the player go through the buildings. 51

It also has an animation, which is the turret animation. 52

We'll get into that a little later. 53

And also an HP system. 54

This will be discussed separately, but I aimed to have the systems as modular as possible so that 55

you can use them in your own project. 56

So basically this is just the drag and drop and basically you can do the same in your own project. 57

The HP system is basically the only system right now that is in the player body. 58

The other systems are in systems. 59

And this is mainly due to the fact that when a projectile enters the collision with the kinematic body, 60

it's easier to just get one of its nodes and check if it has the HP system. 61

Otherwise I would have to parse all this player tree and get the HP system from the other part. 62

And that would have been a little messy. 63

Note that this structure will be followed exactly for the enemy as well, so that the projectile code 64

doesn't need to change if it's the player that's hitting or the enemy that's hitting. 65

The static part consists of the three remaining systems which are the player mover: handling the movement 66

of the player, the targeting system: 67

When the player moves the mouse around, the intersection between the plane and the mouse will be where 68

the target is positioned. And the weapon system that handles the firing of the actual weapons. 69

Now that you have a basic idea of how the player is structured, let's go from top to bottom and deep 70

dive into each one of these and check them out. 71

At the topmost level 72

we have the player script, which is responsible for gluing everything together. 73

What we have in here is of course, some parameters. 74

And then one really important one is this meta "tag", which is type and player. 75

This will be used for projectile collisions. 76

There are two functions that handle the changing of the color of the player tank material. 77

So init_color() which gets the current material from the mesh, I made it so that most of the materials 78

are in the position zero. 79

Then it duplicates (the material). 80

One issue in Godot is the fact that the materials are shared between instances. 81

It's really important that it gets duplicated. 82

And then there is the second function called change_material(). 83

This will actually go through the tank mesh and apply the highlight material, which is our new duplicated 84

material to all the components. 85

Once this is done, the highlight material will get its color change based on the team color specified 86

in globals. 87

So basically this is just a tint of green. The change_material, 88

on the other hand, is a recursive function that means it calls itself and while calling itself, of 89

course, it may call to infinity, but in this case, since the nodes of the mesh are limited, it won't 90

call itself to infinity. 91

So we are lucky if that. 92

What it does, it takes the current tank mesh. 93

In this case this one, and then it parses its children. 94

The tank_turret_normal, tank_body and if the children is a mesh instance, then it will change the surface material 95

to the material we specified, which is our new duplicated material. 96

Note that there's one small hack here, and this is because one of my modelling mistakes: I assigned the 97

material that we want to change on index one instead of zero. 98

So this is not relevant if you do it correctly. 99

Just take this out and just use the first one. 100

Basically this is what it does and of course the change material calls itself, but it calls itself 101

for the nodes. 102

For example, we call it first here and then it's called for the tank_turret_normal and then for tank_body. 103

It goes through these children and through these children as well. 104

And once it doesn't have any more children, then these functions and all of the tree created by them 105

goes up and up and up until it ends and the function eventually stops. 106

Basically this is the logic for this one. Other than this, of course, we do have on_destroyed. 107

And as you see here, we get the HP system and the HP system has this nice signal on destroyed which 108

gets triggered when the HP system detects that the object that it's monitoring is finished, is done 109

on_destroyed here gets called, of course we remove it. 110

But before this we also remove the camera from the camera manager because we cannot allow the player 111

to change the camera to an invalid camera. 112

And here also the UI gets the show response screen, but this is just more visual stuff. 113

Basically this is what we have at the topmost level. 114

One last line here that I mentioned: that in on_destroyed the camera gets free from the camera manager. 115

Of course, the camera first when the player gets instantiated, it needs to be registered to the camera 116

manager. 117

And this is the line that does this. 118

Basically it tells the camera manager that's in the environment, hey, add new camera and basically 119

it adds this player camera. And the camera manager basically has the list of cameras and the player can 120

cycle through that list and choose the current camera via using the [C] (button). 121

By the way, all of the buttons are assigned in project/input map/ and here are all of the possibilities. 122

Move up, move down, left or right, fire, right mouse change camera, and hide_all. 123

Don't worry about the camera. 124

It will respond when the player gets respond and it'll call this again. 125

So you don't have to worry about that. 126

Now let's move to the next script, which is the camera script. 127

And in here most of the code, if not all of it. 128

And actually it's all of it is responsible for shaking the camera when a projectile hits the ground 129

or hits the player or hits an obstacle. 130

So basically, this is a shaking algorithm. 131

What it does, it just moves the offsets of the camera so that, for example, I'm going to use the 132

second camera so that I can show you. 133

So if I do the preview and I do the H offset and the V offset, you see it, it moves the parameters 134

like this. 135

So the primary experience kind of for shakiness of the camera. 136

So nothing fancy is just this. 137

You just shake the camera when the projectile collision hits something. 138

If you look into the tank mesh, we will find the components of the tank, the turret and the body they 139

contain the 3D meshes that make the tank up beside the meshes. 140

There are two other components that need to be there. 141

First, there is the Farpoint, and second there is the tank turret position. 142

Let's discuss a little about the fire point. 143

Basically, what the fire plan does is just the position 3D node. 144

It's nothing visual, but it tells where exactly the projectile should get spotted. 145

So this is really important because the weapon manager needs to know where it just upon the projectile 146

and it should not be the target position, which is you can see it's here. 147

So we don't want the projectile to be spawn here, Mr. Bond here. 148

And there are some other cases, like some other turret types. 149

We actually have more fired points and the weapon manager responsible for that will actually cycle through 150

each file point and fire the projectiles accordingly. 151

Lastly, we need the tank turret position to be specified on the body because the tank turret moves 152

a lot separately from the body and as one of the last steps of the adjusting the turret to its new position 153

is setting it up exactly on the body because as you see, the body also moves. 154

So it's not really that hard to get them out of sync. 155

And lastly, the collision shape is just the collision box. 156

And this also gets adjusted in code because the tank. 157

The body needs to be synchronized with the collision shape. 158

And the question shape needs to be the child of player body, because this is the kinematic body. 159

The animation player holds basically the animation of the turret moving. 160

But here instead of moving the turret on the z-axis, we actually move just the parameter. 161

And this is because for example, if the turret has this position and it moves on the z-axis, it's 162

not the local one, it'll be the global one and it'll move like this. 163

So to fix this, what I did was just the short here animator a parameter, and that parameter gets added 164

to the correct direction. 165

Now let's look at the systems that make the player work, and let's start with the mouse target, because 166

this one is the smallest. 167

So in here, as you see, it's just the 22 lines of code. 168

So nothing special. 169

But what it does here, it takes the current active camera. 170

So regardless if it's the top down camera or the player camera gets referenced here, basically what 171

the script does is create the array from the cursor on the screen to a position in the world and then 172

checks if there was an intersection. 173

So we first need to get the mouse position and we create the array out of that one. 174

And then we use the space state, which is good of functionality to be able to intersect the array. 175

And if there was an intersection then we need to put up the lookup position and this one will be used 176

to actually move the turret around. 177

But there's also a debug function and then this is just a small target. 178

It's invisible now. 179

But if we added a mesh, let's say cylinder mesh, it doesn't matter. 180

And save it. 181

We can see actually where the cursor points on the screen. 182

So this is just for debug purposes, it doesn't have any use. 183

Okay. 184

Now let's remove this because we don't want this functionality. 185

So now let's head over to the weapon system. 186

And what the weapon system does is basically first it gathers input from the player, which is the leftmost 187

button. 188

When it's clicked, instantiate a projectile at the tip of the turret. 189

It handles the cooling down or the reload rate and also plays some animations and effects. 190

Let's go into it and see how this all works. 191

So the first thing that this group does when it initializes, it takes all the turret children and checks 192

if they're five points, basically, if their name has five point in their name. 193

And this is because, as I mentioned, if the turret has multiple fire points, it will cycle through 194

each one of them. 195

And these are the two variables that handle this. 196

So the fire point is actually a list that will contain all the fire points. 197

And the fire point index is basically a number telling which fire point should be fired at this moment. 198

Next, we get the animation player, which is this one. 199

So we need to go up two levels. 200

So the first one would be systems and the second one would be player. 201

And then we need to go into the player body and then the animation player. 202

So this is how we get referenced in animation player. 203

Of course this is hardcoded, but since this won't change, it's fine. 204

Next. 205

We also hook the weapon. 206

Cool, long timer. 207

And the weapon called Long Timer is basically just the go to timer that has specified a wait time and 208

one shot. 209

It doesn't auto start because we want to make sure when the weapon coolant actually happens in the process, 210

which happens every single frame, we just need to check out. 211

If the fire was pressed and if it was, then of course we need to actually fire the projectile. 212

And what happens when we fire a projectile? 213

Well, first we need to check if it's not actually cooling down, because if it is cooling down, we 214

don't want to fire another projectile. 215

Otherwise the player can just spam the leftmost button and it will fire projectiles in. 216

Definitely one thing here, the action just press that means that it needs to be released. 217

If we use is is action press then we can make this work just by holding the most button so I don't have 218

to actually release it. 219

I can just hold it and the player will shoot at the fire rate that we specified in the timer, which 220

is 0.5 seconds. 221

Actually, this is better. 222

So I leave it like this. 223

So what happens when it's not cooling down? 224

Well, two things happen. 225

First, we instantiate the projectile, and then we restart the cooling down functionality. 226

So let's look at the instantiate projectile. 227

So here we need to take the projectile prefab, which is specified here. 228

So export variables are variables that are visible here. 229

And the projectile prefab is just another different good option that's being dragged up from the file 230

system into here. 231

And we use instance to create the new instance of that projectile. 232

Once you do this, the projectile is not actually in the scene. 233

So by using get three root get child, you actually get the main scene route. 234

And why don't we just add the child here? 235

Well, we could add the child here, and technically it should work. 236

But just to make sure it's better to edit at the root level because of the transforms and the position 237

and we have a deep hierarchy of nodes if one no changes the position, for example, when the developer 238

moves the player like this, well, the whole hierarchy inside will actually get position changes because 239

of this. 240

So in order to avoid any kind of issues, we just add it to the main route so that we know that zero 241

is always zero and vector 3.0 is hold is 000. 242

Next we get the current farpoint and as I mentioned, the Farpoint index cycles through all the five 243

points and we need to do the cycling as well. 244

So of course we actually increase the Farpoint index only if we have multiple far points. 245

And then if it reaches the five point position, that means the last one. 246

Then we need to go back to zero and then restart the counting from the beginning. 247

So once we have this in place, we can properly initialize the projectile. 248

And the the projectile in show zation has multiple steps. 249

Of course we need the current fire point, which will give the projectile its initial position and rotation. 250

It'll also give the lookout position, which is the most target. 251

And this is important because the projectile needs to be aimed at this position. 252

The damage can be specified at the projectile level, but it can also be specified that the player level 253

for simplicity. 254

So if you have multiple objects that get instantiated in the player, if you put it up to the player 255

level, then it's easier to customize everything inside. 256

Next, we also specify the color of the project that lands. 257

Since we know this functionality is just for the player we can hardcoded to green team color because 258

the player is green. 259

And lastly, we get the player body, which is the kinematic object. 260

And this is important because we want to avoid the collision from the projectile to the actual player. 261

So by checking for the collisions with the parent and removing them from the beginning. 262

Lastly, in this function, we do a smoke and a muzzle effect and those two are just the visual effects 263

and they spawn at the current fire point and the current fire point origin. 264

So basically nothing special, just the VFX manager handling some nice VFX for us. 265

Next we have the start cooling down and the start cooling down. 266

Basically a variable that tells, okay, now it's cooling down. 267

Then we do a random number generator and this is just for to make it a little different every single 268

time. 269

So this actual wait time doesn't matter because we specify the cooldown from 0.30 5 seconds to 0.70 270

5 seconds and they do a random between them and then we start to call them with that value in place. 271

Of course, we also play the animation turret fire. 272

This could happen at any point. 273

Of course not before this, but here should be also fine to be played. 274

And basically these are the functionalities that make up the weapon system handling the shooting for 275

the player. 276

Now that we know how the targeting and the firing works, let's have a look at how the player moves. 277

To do this, we need to head over to the player mover. 278

And this one is a little big, but don't worry because it's very nicely separated. 279

This will be easily accessible for everyone interested in finding out more how the player moves. 280

But before we dive deep into it, we need to understand what are the exact functionalities of this strip? 281

First it moves the tank up, down, left and right, and please note that these are no top down, left 282

or right for the tank. 283

But from the perspective of 45 degrees, you will understand what this means a little later when we 284

actually see the code. 285

It also applies the gravity. 286

In this case, it's not really necessary because the whole thing is flat, but it does apply gravity. 287

So in case your terrain has hills or valleys, it will work as good as on the flat one. 288

It also what is the turret towards the most intersection the world from the most targeting system and 289

also applies some nice rotations when the tank fires. 290

They're not important functionality wise, but they're important visual wise for the player to actually 291

feel the power when the tank actually fires. 292

So here we just get some parameters in the ready, but everything gets processed in the physics process 293

and it's nicely put in different functions and we'll go into each one of them and see how it works. 294

So first we need to process that direction and get it into this vector. 295

And the direction is basically where the tank is headed. 296

If the player presses one of the following keys, move up, down, left or right specified in the player 297

input in the configuration. 298

So here the tank doesn't move forward back from its own position, but rather if we go to the demo scene 299

and we go to the camera, you can see that here is the tank. 300

So it moves up from the screen, down from the screen, left and right. 301

And these adjustments are actually made in code like this. 302

So for example, if we move up, it's a combination between vector left and vector back divided by two. 303

What gets returned by this process direction is a normalized vector, and that means the vector fling 304

F1 specifying the direction or zero. 305

If the player doesn't press any key where the tank should move next, we need to process the turret 306

and this one does the turret rotation towards the target position. 307

Let's look how this happens. 308

So first we get the target position and as I mentioned, we get the most target and target. 309

And is this one we actually could have gotten it from the code since we have look at the position. 310

So instead of getting the target, we could just get the most target and value look at position. 311

And this is actually better. 312

So I'm going to. 313

Fix this right now. 314

And why is this better? 315

Well, it's because this is mostly for debugging purposes. 316

And if you say, okay, now I'm removing the debug stuff and this gets removed, then this won't work 317

anymore. 318

So it's very important to make it work without the debug as well as with the debug functionality. 319

We need to preserve the scale of the turret. 320

And this is important because all of the transforms that means the position, the rotation and the scale 321

do happen when using different functions on transform, and sometimes the scale might also get messed 322

up. 323

So we need to preserve it and then reapply it a little later. 324

So first we preserve it and then we generate the new transform. 325

So it's not actually we don't use the look that we use looking at which will actually give the new transform 326

to the target position. 327

And this is important because I'm using this interpolate we have, which makes the turret move slowly 328

or smoothly towards the final rotation instead of directly moving to that particular position. 329

And this gives a nice feel for the player. 330

Once this is finished, of course, we reapplied the skill. 331

And also unwanted rotations, because, for example, if we remove one of these and we point close to 332

the tank, the turtle also points down. 333

So we might avoid this. 334

But in case your game has heels and the third needs to rotate up or down, you might want to remove 335

these rotations, or at least the one that handles up and down movement so that the turret can properly 336

rotate. 337

The other one will tilt the turret. 338

So it should always be zero because the turret cannot possibly tilt. 339

Okay, Leslie, here. 340

Once we set up the look at position, as I mentioned, in the tank mesh, we have the tank third position, 341

which needs to be synchronized as the final third position. 342

So we need to set that in place. 343

This is the final third position. 344

But on top of this, we also have getting the turret forward vector which is this long line and multiply 345

this by the turret animation forward and this is the value that gets animated by the animation player 346

and originally it's just zero. 347

So all of this is not used. 348

So the turret gets positioned right on top of the tank body, but when the turret actually fires, then 349

the small animation gets played. 350

So this value changes from 0 to 1, so the turret slightly moves back and forth. 351

So if we quickly play it, you see that the turret doesn't doesn't move forward or back, but if we 352

fire, the turret starts moving forward and back. 353

So this happens because of this line. 354

So now that we have the turret rotation, we can move to the tank. 355

Rotation as well. 356

So the tank rotation. 357

What does it do? 358

It basically rotates the tanks, buddy. 359

So not the whole thing. 360

It just rotates the tank mesh. 361

And this part just the tank by the from the tank mesh because as I said, the turret rotates separately 362

and we don't want to get involved in the player body because some other systems are here. 363

So when does this rotation happen? 364

Of course, we need to make sure that the direction vector is actually a length of greater than zero, 365

because if it's zero, then that means the player didn't press any key. 366

And if a key was pressed, then the direction is either up or down, left or right relative to the tank. 367

And the player body needs to look at that new position and we do the same as with the turret. 368

So we use the looking at to generate the new transform and then we do nice interpolation of that. 369

We have a 2.5 multiplied by Delta. 370

This will assure a nice smooth rotation. 371

Of course you can change this value to make it rotate faster or slower. 372

Of course, to reset the zero rotation to make sure that the tank doesn't rotate up or down as well. 373

Though if would play this, if you look closely at the tank body, if I press up. 374

It doesn't move directly. 375

It moves. 376

It moves with a certain rotation speed. 377

You see how the body moves? 378

It moves so smoothly because of that interpolation. 379

So if you change the value from 2.5 to another one, it will move either slow or fast based on that. 380

So this this doesn't actually move the player. 381

It just rotates the tank, buddy. 382

The player movement happens in the next function. 383

So here, if we go back, this was the tank by the rotation and the move tank is actually what moves 384

the tank. 385

So here, of course, you know the drill. 386

If the lack of direction is greater than zero, then this means we actually have movement and this means 387

we actually have a velocity. 388

And I don't want the velocity to be instantaneously fast or slow. 389

So for this actually opted for acceleration and friction. 390

So what it does it linearly interpolate what the interpolation does. 391

It takes the current velocity value, which in this case should be zero. 392

And the maximum speed, the direction, times speed and the acceleration is what we are multiplying 393

with at every frame to get that velocity to that point. 394

So basically with this, the tank will accelerate to its maximum speed, which is the speed. 395

If there is no quick press, then it will decelerate with the friction. 396

Of course you could have used acceleration, but that would have been weird because as you know, a 397

car might accelerate at different rate as it slows down with the friction. 398

Of course, velocity on the y axis is always -15 or whatever gravity you want to put into this. 399

And lastly, we use the moving slide functionality from Godot. 400

And here we specify the velocity that we just calculated. 401

So this is just the vector three. 402

We have its x and Z components based on the direction and the Y component based on the gravity. 403

And also we need the up vector here. 404

So this will handle the tank movement. 405

And lastly, we have the preposition collision shape. 406

And what this does is actually move and rotate the collision shape to fit the new player position. 407

Why is this relevant? 408

Well, let's see if I comment this line. 409

And they use debug visible collision shapes. 410

Press F5 And as you see, the collision shape is okay right now. 411

But if I move it like this, oh, the collision shape is not in work. 412

So if we go for object, you see that the tank goes through buildings because the collision shape is 413

basically wrong. 414

So if I d comment this back and now we can see that the collision shape nicely moves with the tank. 415

So this is the behavior that we are looking for. 416

So how does the reposition collision shape work? 417

Well, we simply put the new origin of the collision shape to the player tank by the origin, and then 418

we move it slightly on the forward vector. 419

So please know that the fore vector is this with minus. 420

So I'm just putting the minus here in this case. 421

And this is not divide. 422

This is just to go to the next line, because we add this also on the Y axis, because otherwise the 423

collision will go for the floor and we need to be careful. 424

It doesn't do that. 425

We also need to sync the rotation. 426

So this is the slide for this is what makes the collision shape synchronized correctly with the tank 427

body. 428

And lastly, we do have the helper functionality which checks if that is on the on the tank side or 429

the other. 430

And this was responsible for the. 431

The tank body rotation. 432

So this is actually for visual purposes. 433

This is why I haven't been into this before. 434

But what this does, it checks if it's on one side. 435

So this is the X or minus X. 436

So basically left or right side. 437

And if it's one or the other, then it gets thanked by the rotate, which is also a value that gets 438

changed by the animate there when the firing sequence happens and the trot is the tank, by the way, 439

like this or like this. 440

So how does this work quickly? 441

Well. 442

It's a little complex, but I'm going to quickly show it. 443

So first it takes the thing by the opposition and then we get the target, which is the tank turret 444

position and then we get the forward vector of the tank turret. 445

So basically this is where the tank is pointing towards. 446

So now we have a position forward from the tank turret and the current position and this will give us 447

the reference vector. 448

So basically this is just the vector from the tank origin to where the turret is pointing towards multiplied 449

five. 450

And of course, you need to normalize this and the phrase the DOT product and this is a nice functionality 451

for Will because. 452

The DOT product will be zero for a straight angle and greater than zero for angles, narrower than 90 453

degrees and lower for wider angles. 454

So we can check this dot product result of the difference vector to see if it if it's between an angle 455

or not. 456

And what this does in and in practice is that, for example, the angle now is a position that we want. 457

But as we move inside, you'll see, oh, the animation stopped. 458

So here it's where the angle for this side stopped. 459

And then if I move. 460

If I move. 461

Now. 462

Now, the animation started. 463

So this is. 464

This is basically the value that you are calculating. 465

So this one is the value. 466

And if the normal that the product, the value of this one is within the range, that it will it will 467

give us the result we wanted. 468

If not, nothing will happen. 469

So basically this is what this function does as well. 470

So this is the player functionality. 471

I hope you liked it. 472

It's a little big and some of it is just for polishing. 473

So it's not for functionality. 474

But do remember that in finalized game products this is super important. 475

So make sure that your game has visual effects like these. 476

This is it for this video.