All language subtitles for 32. Preventing Invalid Spawning

A problem that we have is that

Our enemies in our game will spawn outside of the walls which obviously is not

Deal because then well

And this

Is wrong

So

And luckily I think the fix is going to be

Free simple

So let's go to our enemy manager and open up that script

And are my manager

Is responsible for

Spawning

Anna

Now what we are doing to determine response position of the enemy is there a centrally just getting a randomly

Updated unit vector

Then we are multiplying that by the spawn radius of an atom

The player position

Of course the problem being that

If we are pointing in Direction that goes past a wall

Then the enemy will spy outside the war

There is a fix that

I think is going to work really well on the situation

And is essentially that we're going to do a raycast

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Determine

If this one

Is valid

It's going to be a little bit tricky because we still want the enemies to spawn off screen

So we need to figure out what we gonna do when we

Counter

Collision

And Eric as essentially online along

You check for

Collisions

So we can pick a start position in end position

And we can

Godot

Is there any terrain collision

On this line between them

2 points

If there is a collision

Then what we're going to do is we're going to change the direction

That the enemy is going to spawn

And what we'll do is we'll check it up to 4 time

Rotate

The direction by 90 degrees

Every time until we find an empty space

If that doesn't

Seem super clear yet don't worry it should be a little bit more clear as we get into

So

One thing I'm going to do is I'm going to create a new function that is designed solely for the purpose

Getting a spawn position

Someone who creates a new

Function below the ready method and I'm going to call it

Get

Spawn

Position

And what I'm going to do is I'm going to

Grab this line here

Is this tree line swear

Getting the player

I'm going to copy and paste that up here

Now instead of returning just nothing out of this function

All you want to do is we want to return

Instead

Vectra 2.0

So we gonna play position is going to return

As the position

Should be fine because

We are returning early out of this on timer timer anyway if the player doesn't

So theoretically we shouldn't even get to this point but it doesn't hurt to be ale

Ok

So

Next I'm going to take these two lines and on time or time out the random Direction

In response

I'm going to cut those out

And pay stores

And then in the on time or time out let's go ahead and just replace those lines

We cut by doing

We can replace this actually down here so on this earring line and my back and I what position is it going to sponsor edition

Wishes change that sponsors is near to

Get sponsored

The weekend

Call the function right there

My

And that should

Work just

Ok

So up here if we want this to be functionally the same as what we had before

We can go ahead and return

Spawn underscore

Position out of this funk

So that's going to

Essentially be functionally the same

Where does going to return the position at so

In this part of the function is where we went to actually manipulate the direction if it's not

Appropriate

Where can I want to do a reiki

Check as a man

Earlier in the where we can do that is we actually

Query what is called

The

Space state

An essentially that is the current

8 of the physics objects in the game

Against which we can

Run various checks

In the way that we can retrieve that is

I'm going to write

Get

3

Start

Route

Start work

Underscore 2D

Space

And this is going to be our 2D physics Direct space state is what it's called

And we can do is we can actually

Intersect Ray against

State

And what is intersex

Require as argument while we can open up a documentation and look for intersect

Underscore Ray

Find the definition Henry

Physics

Nextbase

Open that

And we can see that this takes a physics

Aquarium

2D

So let's go and collect

This is an object that we need to

And we need to

Created with

Argument list

Here now this is going a little bit off

My screen here

So we're going to have a from which is affected

A tool which is another

And then a collision mask which is

The same exact thing that we see in our editor over changing the layer and

We are going to be mostly using

Is first three

So let's go back to my manager

Let's just

Above this line

Create a new variable called

Query

Perimeter

I'm going to say physics

Ray

Studio.com cos that's the method

That we were just

In our front position is going to be player.dat global position

Set a start position

And the position is going to be this random

Sometimes spawn rate

So we actually had the stored as sponsors

So I'm going to do if I'm actually just go

Did you copy these

Or rather cut these lines

That we just

I'm going to go ahead and move those on

Ok

So you're cold you look like this

And for the second argument here we're going to pass in spawn position

And then our

Leia

Or our mask ready that we want to check against it's going to be the same so if I open up

Play adjust reel

We have in the inspector here

Nicola and occlusion

You can actually hover over

The mask and I will tell you

B

The thing about

Doing the rear car

Collision

Code is actually need to pass in

The bit value already

Int value that corresponds to the b

The mask

So b 0 as a value of 1 which you can see

In the toilet

When you hover over the terrain Valley

That's the value that were going

So we can write

One in there

That's going to collide with

The train Leia

Now another thing that you can do is

You can actually use

Shift

You want

So

I can say one

Shift

Over 0

If you're not familiar with bitwise operators

Essentially this is just saying

Take

1

Which under the hood has a bit value of 1

And shift that bit over

This many people

And the reason is that useful in terms of the terrain is let's say that I had my terrain

Set

24

Right let's do something little bit

Differ

Let's say 2

So if my lair was too

I would

Type out manually this value

524288

That's not

Really that

Comfortable to wear

Encode Manor

I could do if I could take one

And since this is

B 19 I could shift it 19 bit

And that will

Create

That same Val

So if I had my mask set to let one

I could simply do one

Bit shifted 19 plate

And that you can easily sort of reference

Your mask

Code

With bitwise operators but fortunate

We're simply using

The first bit

As our terrain layer so it

If that's not superclear I'm encouraged you to go ahead

And do some research

Bitwise operator

It's a very handy tool to know

But we'll dropped

Cancer

Therefore now and continue on with our

Ray intercept

So now that we've got are query parameters

Constructed

We can pass those in

The Intern

And we want to store the

So we're going to say virus

Get 3

All that

Another question is what happens if we don't have a recall

If you don't have a rear collision what will happen is result will be now

So we can see if result is

Then that means I just read a comment

Pound

We

Arkley

Else

We have a car

I'm going to write pass in here

This is not

Complaining

That's just a quick of gdscript you've seen as use passe

The Times basically every block of indentation

Need to have

Some sort

Statement or a line of code and passes just basically a placeholder that says

We are doing anything here yet

But we do want to maintain

The inde

We want to maintain the Blacks

Ok so if I was articles

Let's do this just for testing purpose

If the result is no we're going to go ahead and

Return

Spawn underscore position

And if it's not know which is return the player that the whole position this is not

This is not the final behaviour that we're going to watch

Can you remove the return

At the end here

Is the data final functionality that we want but this is going to make it really clear when there was a train collision because the answer is going to

Ride on top of the player

So let's just run this to make sure that we've done everything correct

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And you can see that already got an anime couple of animals that just spawn on top

Tyres always returning a collision in why is that

That's because

If you read the documentation for intersect you can see that

It says at the end if the radar not intersect

Empty

So this is why reading the documentation is really important

I made the assumption that it would return

Noel if the result

Did not return

Collision

But that's not actually true

Return

Auntie dictionary

Different than no write an empty dictionary actually nom

It just doesn't have anything

We need to do a slightly different check which is a

Result.is underscore

So this is the way that you can check if a dictionary has

Cheese

And

That means letters

North no collision and we can transport position so let's run again

We can see now that hopefully some enemies are going to

Spawning outside of the

Game window and then if I get closer to a wall

You can see now all of a sudden

Enemy spawning on top

As soon as I move into the middle of the screen

That should no longer be happening because we are far enough away from all the wall

So what are we going to do about

In the first part of this lesson that we're going to do if we encounter a collision is a basically just going to rotate

The direction that were looking at

Or that we're looking to spawn the enemy

Rotated by 90 degrees

Sofa demonstration purposes

Here is a corner of my map

Right and then let's say that here is my Play

If I'm choosing to spawn an enemy

In

Let's say

Distraction

And that ends up at the college

If I

Rotated by 9 degrees

It's going to end up looking like this

But I can rotate it by 90 degrees again and like this this is going to end up being empty space

And this 9 degrees is

Collision

So the idea is because our room is a

Tangle it should be the case that no matter what

Corner or wall I end up going to

Have two players here

No matter what direction gets chosen

Like something like that

There will always be a 90 degree in cream

That ends up being clear

Of any colours

I hope that makes sense

Let's go ahead and implement that

In the way that were going to do that is were going to use a 4

Now what is a fool

Afford

Essentially Lazarus

Iterate a specified number of times either over

A specific number of

Elements or a variable number of elements in a

Play some Erasure

And how are you this is

So there are four

90-degree

Instruments that we can do it right

There's the first direction in an iterator by 9

And is rotated by 9

Is 30 by 90 again

So what we going to do is this a 4

I in

4

Now the thing to note is

This is going to increment I

Going to start at zero

When is gonna incremented by 1 every time before Luke and

So when we first run code in this block where this passes

I will be 0

It will run again

I will be one

Anything to note is that this is not

Include

So4

I will never be fair

I will only be a maximum of

3

So that's just something to be aware of when you're using a form

Like this and what we're gonna do is we're gonna move

Holidays code

Except for this

Black

Into

That for loop and make sure everything is properly and

This is what it should look

We're going to declare spawn position above the for-loop so let's go ahead and declare a variable

1 position

And let's just said it to

Player that global position next week doesn't matter live that's actually said it to them

Just so that it initially

2A

Vector

Ok so good to Dad's

Now we're just having a beer and that's fine let's get rid of this via because we can't read it there a variable but we can we

Sign do it in a totally doing here

And we can actually break up

This

If else block so let's

Delete the else

Let's take this if result is my

Invented by 1

An Audi Galway because were in the correct context here

And I want to remove this car

So the thing about 4 so you can return early out of them as well so if your return in a for loop and let's say it's only

The first iteration to actually stop

So we can return early so that we don't have to go through all the loops if the first

So I can spawn position

Is

Valley

Then we're gonna do is we're also going to move the random direction out of this for

Just above

Initialise the random direction to a random

Ok so what we left with is we are left with this look

The final thing that we want to do is we want to put an else after this if result is

MD

And this is the part where we

To change

The

Angle

Of the random diary

So we can say random Direction

Is equal to

Random Direction rotate

And hour angle in here is going to be in

Radiance

So just to make it easy we can do

To read which is a function that will

Degrees in converted to radians

How much pudding

So re-assigning a random Direction

To the random Direction but rotated by 9

And then the loop is going to restart if this else block

Wasn't

Now the last thing we need to do is

Outside of a form

We just need to return our sponsor

As The Returned

Ok so let's just stepped through this logic again just to be extra sure

But everything

So we're going to assign initial spawn position in an initial random Direct

Then we're going to in The Fall

In each iteration were going to take a sponsor

We're going to say it's equal to the players current position Plus

The random Direction which is a unit vector which means a vector of length 1

A x a spawn rate

And those two added together is going to be our new composition that were cancelled

Then we're going to create a raycast query

Using the player position and spawn position

The start and end points

The rake

And we're going to be checking again

The terrain layer

4 Acre

Then we're going to actually do the intersection Ray

Call

To see if that rare

We define a peer interest

Lights with

Terrain

And that's going to be stored in a result dictionary

If the result is of being empty

Then we're going to return that spawn position of here that we talk

If it's not empty

We want to change the random Direction by rotating at 90 degrees

Anna Lowther

To start again

And redo all

And so what's going to happen is we're going to check

Up to 4 raise

Until we find the one

That is not colliding with

Train

And that spawn position the last

Set spawn

Will be

Return

From our

Now what I'm going to do actually to make it a little bit clearer what's going on

Is I'm going to remove this return spawn position from this result is empty and he's a different keyword called

And what break does is that tells the loo

To stop execute

To stop going

Even

The loop isn't tag

Play finished

So this is a nice way in addition to returning

We can just break early out of loop

I think this makes more sense as well

Because we returning spawn position at the end of the funk

Editor seems clear to me like ok we're just going to

What is going to stop

Once we find a spawn position

That is valid and then we'll go

Let's Run the game and make sure all of that is

If I go onto the corner of my map

I should see no enemies coming from this direction

They should see enemies

Coming from

And so far I have not seen any

Please come from outside of the wall

So I think we can say

That this

Is

Fixed