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  • (train horn)

  • - Happy back to school.

  • It is August 31st, school for me starts next week.

  • On The Coding Train, I am going to

  • attempt to do a classic again.

  • I am going to attempt to do a coding challenge

  • and pick the Snake Game.

  • And yes, I have done this before,

  • but I'm going to do this in order to celebrate

  • something that was announced today,

  • the P5JS web editor.

  • (audience cheering sound effect)

  • So the P5JS official web editor is out

  • and I'm going to try...

  • The nice thing about this is when I code this,

  • at the end of it, stop with the sound effects,

  • at the end of this, you will be able to just go directly

  • to this URL, which I will include in the video description,

  • and hit duplicate.

  • You'll have to make an account for the web editor,

  • hit duplicate and then make your own version of it

  • from my code and share that with me.

  • So I will include all about how to do that

  • in the video description and I'm going to give myself about...

  • Oh, my watch isn't on.

  • There's not timer but I actually have to go,

  • I have to be home very soon so I'm going to give myself

  • about 20 minutes, which of course, this is going to take

  • longer than that but let's see how it goes.

  • All right so however long this video is,

  • is however long it takes.

  • Hopefully, there will be no edits.

  • Everyone once in a while, you know,

  • there just has to be an edit

  • 'cause the whole system crashes.

  • I better get coding.

  • (deep exhale)

  • Snake game.

  • Have you ever played the Snake Game?

  • The idea of the snake game

  • is there is a

  • canvas,

  • you are a dot, like a little square on that canvas.

  • Another dot, or another little square, appears,

  • which is a piece of food.

  • You want to move,

  • you can only move to the right, up or down, along,

  • grab that piece of food.

  • Once you grab that piece of food,

  • a new piece of food appears somewhere else

  • and you get a little more on your tail.

  • You get another piece of your body

  • and you get the next piece of food and it gets longer

  • and it gets longer and anytime you hit the edge,

  • if you run into one of the edges,

  • you die, the game's over.

  • Or if you hit another part of your body,

  • and it becomes much harder

  • as your body gets longer and longer.

  • That's the snake game, that's what I'm going to code.

  • So in order to do this,

  • I'm going to use object oriented programming.

  • In my previous version of the coding challenge,

  • I used like this constructor function thing

  • and now we have ES6 classes.

  • I want like a happy sound (horn blares).

  • So one thing I'm going to do is I'm going to show you...

  • Andby the way, if you want to know all about

  • the P5JS web editor, check a link to a Medium article

  • that is in the video's description

  • and a whole bunch of videos from the Processing Foundation.

  • THere's a nice video with Cassie Tarakajian,

  • who created the editor, describing all of it's features.

  • But one feature is that I can go over here

  • and find this little (tongue clicks) thing,

  • this little tick, less than, greater than sign.

  • Whatever it is, and I can say, "Add file."

  • And I'm going to add a file and I'm going to call it, "Snake.js"

  • and now, I have a file called, "Snake.js"

  • where I can create the snake class.

  • Now, if you've never done object oriented

  • programming before,

  • the idea is that this is a teth-link

  • for this snake object that I'm going to make in my code.

  • And it has a constructor function.

  • I will refer you to my tutorials about

  • broken object programming ES6 classes.

  • Now...

  • But in order for...

  • I need to actually go into index.html

  • so that

  • the page, when I run the code,

  • is actually using both sketch.js and snake.js.

  • So that's there.

  • So now I have sketch.js, which is just a...

  • Oh, and I need to see this.

  • A 400 by 400 canvas.

  • And snake.js, which has nothing in it.

  • But

  • what I'm going to do is I'm going to say, let snake,

  • and end setup,

  • set-up being where the code starts

  • in a P5JS sketch.

  • Snake equals new snake.

  • So I've made a new snake and what do I want to do?

  • And I want to update the snake's location every frame

  • and I want it to display it.

  • So the idea here is I want to say Snake.update

  • and I want to say snake.show.

  • I'll use show as meaning show yourself, display.

  • Hmm, what is this?

  • Snake.update is not a function.

  • Oh come on, I have to write the code for it?

  • Yes, I have to write the code for it.

  • So if I'm going to write a function called update,

  • that means I have to put a function in the snake class

  • called update

  • and then I have to put a function called show.

  • Ta-da, I'm done.

  • Coding challenge complete, snake game not all.

  • So this is like the skeleton of the code

  • but I actually need to put stuff in here

  • and I'm going to hit shift tab to tidy up the notation.

  • Okay,

  • what do I need?

  • So I'm going to do something a little weird.

  • I know that what I need is an array

  • because even though the snake's position,

  • you could think of as like a single X,Y location,

  • I botched this the last time I did this.

  • Really, what I want is an array because

  • I want to keep track of a list of all of its locations.

  • And maybe the first element and probably, more easily,

  • the last element of the array.

  • When with only one thing,

  • is it's the sort of head of the snake,

  • the front part of the snake.

  • So I'm going to do that.

  • I'm going to say

  • this, I'm going to call it a body, is an array

  • and then I'm going to say, this.body index zero.

  • I'm going to put one thing is createVector.

  • Now, createVector is a function in P5

  • that creates a vector object and that vector object

  • has an X and a Y.

  • So I'm going to create it at zero, zero.

  • And then in update, I'm going to say

  • this.body index zero.x

  • plus equal this.xspeed

  • I'll call it xspeed or xdirection or something

  • and this.body.Y, index zero.y equals this.ydirection.

  • Oh, this is so ugly

  • but it's the way I'm doing it, right?

  • Instead of having...

  • It's a little weird like really, it's just one thing

  • that's moving around, I just have an X and a Y.

  • Instead, I have a body index zero X

  • and a body index zero Y because later,

  • imma get to add more pieces to the body.

  • So if I run this, what's this.xdirection, this.ydirection?

  • Doesn't even exist so those are going to be variables

  • that tell me is the snake moving to the right or left?

  • Is the snake moving up and down?

  • So those values,

  • this.xdir will start them at zero.

  • (deep exhale)

  • So there's zero and so...

  • And then show.

  • I am going to do something, I am going to say...

  • What do I want to do?

  • Showing the snake is drawing a rectangle.

  • I'm going to do something a little bit weird.

  • So I'm going to draw...

  • Again, eventually, this is going to become a loop

  • 'cause I'm going to be drawing all the pieces of it.

  • But let's just start with putting in the X and a Y

  • and I'm just going to say, I'm going to make it 10.

  • This is going to be a little weird.

  • Actually, 10 by 10, the rectangle,

  • and I'm sorry that you can't see

  • all the code, let me...

  • I'm not used to doing challenges with the web editor

  • so let's see if I can make this a little bit wider.

  • There we go.

  • So okay rectangle and then

  • say fill zero,

  • just to make it black and look at that.

  • Already, I see that...

  • I better save this.

  • Oh saved a minute ago.

  • It's auto saving, that's wonderful.

  • There it is right there.

  • Let me make X direction one.

  • (groans)

  • Oops, two equals by accident.

  • Look, it's moving now, right?

  • Because the ID in update the body's, head's

  • X location is increasing, right?

  • If I made this 100, it's moving really, really fast.

  • 10, it's moving pretty fast.

  • If I change this back to zero and make this one,

  • it's moving down.

  • I could do all sorts of weird things, make that five.

  • But that's not, no longer in the snake game.

  • The snake game, by definition,

  • I can only move horizontally or vertically.

  • So I'm going to start these at zero

  • and then I'm also, just right now,

  • I'm going to change this to one.

  • I'm going to explain, I'm going to do this in a funny way

  • that I think might work well.

  • It's a tiny little dot, a one pixel dot, that rectangle.

  • I am going to now, in sketch, I am going to have

  • the keyboard be the controls.

  • So I'm going to say, keyPressed.

  • Oh, I forgot how to do this already.

  • (chuckles)

  • So if

  • key

  • equals

  • up,

  • what is it in P5?

  • Basically keyPressed is an event

  • that whenever I press a key, this function happens,

  • that I can check what key did I press.

  • But I totally can never remember

  • how to write this function.

  • So let's try and look at the P5 reference.

  • Somebody maybe in the chat will tell me.

  • Let's look at keyPressed.

  • If value equals zero, no.

  • If keyCode equals left arrow.

  • This is good, this is what I want.

  • It's the keyCode.

  • So key is for

  • which character I press but if I'm using the arrows,

  • I need to use left arrow erase.

  • Let me actually just grab this

  • and I'm going to say if keyCode,

  • and I know I can use this switch statement.

  • I'm just not going to right now, okay?

  • (sniffles)

  • Please don't, don't at me.

  • That's what I'm supposed to say.

  • Somebody taught me that who's younger than me.

  • (chuckles)

  • keyCode equals left arrow,

  • keyCode equals right arrow,

  • doing a terrible job at paste,

  • paste,

  • down arrow,

  • up arrow,

  • ah.

  • Don't hide.

  • Auto format, there we go.

  • Okay.

  • So now what I want to do is if it's the left arrow, then

  • snake.setdirection

  • this is the way I did it before, I remember.

  • Left is negative one to the...

  • Negative one along the X

  • and zero along the Y.

  • So I'm going to write a function that's like saying

  • set the direction.

  • So this is for left,

  • this is for right,

  • this is for...

  • (moans)

  • I'm so freaked out.

  • Down,

  • I'm remaking this video, why?

  • This is for

  • up,

  • negative one.

  • Okay, tidy code.

  • So I think this is the right idea.

  • Depending on which key I press,

  • move the snake in that direction.

  • So now, I can say...

  • I can write this function, setDirection

  • and I'm getting an X and a Y

  • and I'm just sayinf this.xdirection equals X,

  • and this.ydirection equals Y.

  • So whatever comes into the function sets those things.

  • The people, I can see the chat over there,

  • "Please do a switch statement."

  • No,

  • duplicate my code and change it and make it better,

  • use a switch statement.

  • Okay.

  • So now, I'm going to do this, lets zoom in, here.

  • Let's see if this works.

  • Come on, no, I have to click 'em.

  • Yes!

  • Down, look at this.

  • So now it's working, right?

  • So I'm pressing all the keys and I'm moving it around.

  • Perfect.

  • Now, I need to deal with something.

  • I don't want to have to zoom in, it's so tiny.

  • So ultimately,

  • there's an issue here.

  • I want to think about the snake in units of one.

  • Here's my snake, it moves one pixel over,

  • it moves one pixel over, it moves one pixel over.

  • But I have a canvas that's 400 by 400

  • and I probably want to draw is as a 10 by 10 thing.

  • So I want to have a variable,

  • I'm going to have a variable, I'm going to call it R-E-Z,

  • short for resolution.

  • Can you see that?

  • And I'm just going to make that 10.

  • So that variable, and actually, to be honest,

  • I could just use, you know what I could do?

  • I could just use the scale function.

  • I'm just going to use the scale.

  • So I was going to use math

  • and I was going to always multiply it's X location

  • by that resolution.

  • And use the resolution for the width

  • but the truth of the matter is P5 has a scale function

  • so I'm going to say let resolution equal 10

  • and then in the draw function, I could just say

  • scale by resolution.

  • And what that's going to go, and notice like

  • see, look at that, I can change this to 50,

  • I can make this 10,

  • I can make this 100.

  • It's just scaling it up and if I move this to the...

  • And so now, if I make this 10

  • and I move to the right,

  • it's actually moving every 10 pixels, also,

  • 'cause when it changes by one,

  • it moves 10 and I could...

  • What I might want to do is, you know,

  • normally, I want the animation to go really fast

  • but imma change the frame rate to five,

  • just to slow it down

  • so we can what's...

  • What's a little tricky here, when using the P5 web editor

  • is I need to click over here

  • to give this preview page focus

  • so that it gets the key commands.

  • So now you can see it moving over.

  • And this, you know, this can...

  • The frame rate, typically, I don't want to slow the frame rate

  • of the the animation down.

  • But this is a way I can control the speed of the sketch.

  • So this is what I'm going to do,

  • okay.

  • (deep exhale)

  • So

  • now, I need...

  • Ah, okay.

  • So I need to have a food, a piece of food.

  • So I'm going to make the piece of food

  • just a vector.

  • At some random...

  • I could make a food class but I think that's overkill.

  • I'm going to make it a...

  • Ah, okay.

  • So here's, now, a tricky thing.

  • I want the food...

  • Okay, let's say my sketch is 400 by 400 and really...

  • So really, my world

  • is 40 by 40 but I scaled it up by 10.

  • So I need a variable

  • to keep track of actual dimensions of the world.

  • So I'm going to say...

  • I'm going to use W, well, I don't know.

  • I'm starting to think of columns or...

  • I'm going to say W.

  • Equal...

  • I'm going to actually just put let W and let H, here.

  • So I'm going to say W equals floor width divided by resolution.

  • So what is this?

  • Width divided by resolution is 400 divided by 10,

  • which is 40.

  • And the reason why I'm using floor there,

  • is just in case my math is off,

  • I want W to be an integer, a whole number,

  • that will take off the decimal place.

  • H equals floor height.

  • And of course, it's a square,

  • so I don't really need to add the two separate values

  • but your window might not be a square.

  • There, okay.

  • So...

  • So now that I have that,

  • why was I doing this again (chuckles)?

  • Oh, the food.

  • Because now, I want to get

  • an X position and guess what?

  • I remember this from before.

  • I'm going to write a function,

  • food location, foodLocation.

  • And what happens in this function

  • is I pick an X, which is floor random W

  • and a Y.

  • Floor...

  • So I need a spot, random H, right?

  • I need to find a random spot for the food

  • and set that there.

  • And then in draw, I'm going to make the food

  • a red, I might be standing a little in front of the code

  • but hopefully this is okay.

  • And I'm going to say rectangle food.x

  • food.y one, one.

  • So you know, I guess I could make it a point or something

  • but it's just

  • everything is of unit one

  • scaled up.

  • Okay, can I...

  • Oh and I need to actually call

  • at the beginning, foodLocation.

  • And Y, oh, it's not...

  • You know what I need to do here?

  • Is I need to say

  • noStroke.

  • That stroke is getting scaled in a strange way

  • so this is actually 10 by 10 pixels.

  • It was much bigger

  • because with a stroke there,

  • that's getting scaled as well.

  • So now we can see...

  • Woops.

  • If I click over here, we can see and eventually...

  • Come on, get that piece of food.

  • Okay so now, good, so this is working.

  • Ah, the snake game is working.

  • Oh, this is good.

  • This is much better than I did before.

  • (chuckles)

  • Helps to do this a second time

  • even though that was a couple years ago.

  • Let's make this 20

  • just because I want to be able to see it better.

  • Okay so that's good.

  • Let me just make sure things are lining up, excellent.

  • So now, I need a test.

  • I'm going to say snake.eat food.

  • So that means

  • I need a function and let's put that...

  • I don't know if the order matters so much.

  • I'm going to put this here.

  • And I'm going to say,

  • eat

  • food, I'm just going to make an argument called position

  • so basically, the food is getting passed in here

  • and I'm eating the food if now, this is a really,

  • probably a bad idea because you never know,

  • in java script, if you've really got the number

  • like three or if by accident, you have the number

  • 3.00000001 (laughs).

  • But I'm going to test, in theory,

  • if the X, Y of the head of the snake

  • is the same as the X, Y of a piece of food.

  • If they're equal, I should be eating food

  • so let's...

  • Let's just see if that works.

  • So I'm going to say

  • if...

  • Well first, let X equal...

  • Let's just put this in a separate variable.

  • Let Y equal this.

  • I'm going to get that head of the snake location.

  • If x equals

  • pos.x and y equals pos.y,

  • then

  • return true

  • and also say

  • console...

  • Console, I'm going to say print.

  • I could say console log print food eaten.

  • Okay so let's see if this works.

  • It's a little bit dangerous, a little treacherous

  • and I'm going to say return false, otherwise.

  • And then, in the sketch, I'm going to say, if...

  • If, I'm going to have this return something,

  • if you eat the food,

  • then you just need a new foodLocation, right?

  • So immediately, you should pick a new random location.

  • Okay, let's try this.

  • (scoffs) I missed it.

  • Ah, I can't get it.

  • Oh, so that's working.

  • All right so I think all my flooring of the numbers,

  • you know, maybe I need to have some better...

  • This seems to be fine.

  • So I'm going to live with that.

  • I'm happy with it.

  • Okay so now,

  • we are so close.

  • What do I need to do?

  • This is going remarkably well.

  • (knocking)

  • That's a sure sign for something to go wrong.

  • I'm going to say

  • this.grow.

  • If I eat the food, I want the snake to grow.

  • If I'm calling a function that I intend to be

  • part of the snake object, within the snake class,

  • I need to reference it by saying this.grow.

  • So that means I need to write another function, grow.

  • And what that means is I want to expand the array.

  • (deep inhale)

  • Okay, okay, ooh, this is the tricky part (groans).

  • This is where everything went wrong before.

  • I'm not even looking at that chat,

  • there's a chat going on,

  • I'm sure everyone's screaming at me.

  • (chuckles)

  • I'm going to add another variable,

  • this.len for length, length of the snake

  • and it starts as one.

  • So if that, at that a minimum, I know when I want to grow,

  • I want length to go up by one.

  • I want the length to increase

  • and I need to add something onto the array.

  • Add something to the end,

  • add something to the beginning,

  • this is unclear to me.

  • So first of all, let's try...

  • So let's just try saying

  • this.body....

  • So first, let me get

  • the last...

  • I'm thinking about this.

  • You know what?

  • I think this is going to be...

  • I think, actually, this is simpler than I think.

  • Let's just try saying this.body.push createVector.

  • So I'm just going to push a blank vector into it.

  • I know I need something else in the array

  • so let me just...

  • And push it so that it adds to the end of the array,

  • maybe I want to put it at the beginning.

  • I'll figure that out in a second

  • but I'm just going to push at the end of the array.

  • And actually, now, I'm realizing the flaw in that

  • but that's okay.

  • Yeah so actually, so pushing...

  • I could put it in the beginning

  • and that would actually work, I think.

  • But okay, we're going to figure this out.

  • I'm trying to think it through

  • so it's easier to think it through, just code it.

  • So what I want to do now, this whole thing...

  • So first of all, what this mean is anytime

  • I want to draw the snake, I don't actually want to draw...

  • I don't want to draw

  • just a single rectangle,

  • I want to draw all the rectangles.

  • So I'm going to say...

  • I could use like a for of loop or something

  • but I'm just going to say,

  • I'm just going to use a regular, old fashioned

  • this.forloop, this.body.length,

  • I plus plus

  • and then this loop will go around here.

  • Uh-oh, oh no,

  • oh no.

  • (buzzer buzzes)

  • Oh no!

  • I've killed the editor.

  • Let's see when it last auto submit.

  • I'm going to quickly click off this auto refresh.

  • And where did I last leave off?

  • (yells)

  • That's not so bad.

  • So the last time it auto saved was here

  • and I am going to...

  • I'm going to retype my loop more carefully

  • without having auto refresh on.

  • I is less than this.body.length,

  • I have to more this, now, back all the way over here.

  • I plus plus

  • and I'm going to auto format that

  • and I'm going to say this.body.i

  • so now I'm drawing every element in there.

  • Okay.

  • So now I'm going to hit save.

  • Project is saved so I have that.

  • Oh, I lost what I wrote in grow (chuckles).

  • Live and learn.

  • Move this over here.

  • Oh, oh right, 'cause I had this open, that's why.

  • So this actually comes back here.

  • So grow, what did I do in that?

  • I said this.body.push createVector

  • and I said this.length.

  • I don't know if I need this length variable,

  • to be honest 'cause by definition,

  • the length of the array is the length variable.

  • (chuckles)

  • I'm so sad.

  • And then did I add that?

  • Then I added that.

  • Let's see, I lost some code.

  • You're not working...

  • You're not really coding if you don't lose some code

  • every once in a while to an infinite loop.

  • Okay.

  • So here, we're good.

  • Now this...

  • What's going to happen here is really weird

  • but I'm going to get the food.

  • Oops, shoot, I missed the food.

  • So interestingly,

  • why am I not seeing...

  • I would imagine that I would see another...

  • So one thing, I would guess that I'm going to see

  • another appendage but it would just be at zero, zero.

  • Oh, look at me, look at this, push createVector,

  • createVector at zero, zero.

  • Let me just do that.

  • So that, I forgot.

  • So what we're going to see here

  • is this.

  • There we go.

  • So that second part of the snake is there

  • but it's up there.

  • So what I need to do now

  • is when I'm updating the snake's location,

  • I'm going to comment this out for a second.

  • The first thing that I want to do,

  • and there's shift, okay?

  • There's an array function called shift.

  • I forgot one.

  • Last time I did this, I didn't use that,

  • I just manually moved all the spots in the array.

  • Let's look at array javascript shift.

  • I don't actually know what this function does

  • but everyone was telling me I should do it.

  • Shift.

  • Oh, look at that.

  • That's so perfect.

  • So this is what I want,

  • I want to shift all the elements down one

  • and I guess I'm losing one.

  • So let me just see about,

  • let me see if I understand this.

  • So

  • just in the console, let me practice this.

  • Let array equal five, six, nine, 100, five.

  • So that's what in the array

  • and if I say array.shift,

  • woops, no.

  • That's what it returns.

  • Did it shift it?

  • But it shifted.

  • Oh so it's giving me the thing that it got rid of

  • and then it's making it one less.

  • So this is perfect, this exactly what I need.

  • Oh, I love it.

  • So actually, all I need to do,

  • every time in update, is say this.body.shift

  • and then that's moving everything over

  • and then the last spot

  • so one thing I need to do

  • is let me save where it currently is.

  • So let me pop...

  • Pop doesn't remove it from the array, right?

  • So if I say array.pop,

  • that gave me the element five

  • but the array still...

  • Oh no, I got rid of it.

  • How do I get something off the end

  • without removing it?

  • Oh, un-shift adds from the beginning.

  • That's interesting.

  • How do I get the last element

  • without removing it?

  • Well, I'm just going to do it the manual way,

  • this.

  • I'm just going to say let head equal this.body.

  • And this.body.length minus one.

  • That's the last element .copy.

  • So this is me taking the last element

  • and making a copy of it.

  • And then what I want to do is say head.x plus equal

  • this.xdirection head.y plus equal this.ydirection

  • and then I just want to put that back on.

  • So I want to like save where it was and then move that

  • and then the body is all there.

  • Yeah so I'm being told this is actually how to do it.

  • So that's the last element, copying it.

  • Let's...

  • So one thing that I want to do, what's wrong here?

  • This.body

  • index this...

  • Cannot read property copy of undefined.

  • So do I not have...

  • Oh, because I'm doing it after shift.

  • And if I'm shifting something with zero...

  • Yeah, if I'm shifting something with zero...

  • So shift has to happen after, right?

  • 'Cause if it only has one thing in it,

  • I shift it, it's gone.

  • Okay.

  • So this is working, now.

  • Oh look at that, so this worked.

  • (laughs)

  • And it made it longer but it created it back at the start

  • so I need to keep that location when I grow it.

  • So the same thing I need to do here,

  • in grow, what I want to do is not add.

  • What I want to do is

  • do this exact same thing

  • and then push, right?

  • I want to take the last one

  • and add it to the end.

  • So I need to just duplicate where it was before to the end.

  • I think this should do the trick.

  • Yep.

  • Is it...

  • Am I going one step behind by accident?

  • I'm not sure.

  • That's pretty good.

  • I don't know why the food...

  • Oh.

  • Oh, you know what?

  • It's not getting in until I get to the back.

  • Why?

  • Because eat is always checking this one.

  • I need to check the last element.

  • Same thing, this is very awkward, the way I'm doing it.

  • And

  • I'm sure somebody will make their own version

  • that's less awkward but I need to check

  • the location of the head against the food.

  • Here we go, let's try this one more time.

  • Snake game go.

  • There we go

  • and up.

  • Yeah, this is better.

  • Okay, great, this is working.

  • Yay!

  • All right, now guess what?

  • One more thing.

  • I need to know when to restart the game.

  • When do I die?

  • So I'm going to do...

  • I'm going to do a function called like check, you know,

  • check for death or like I don't know, endGame?

  • And what I need to do is I need to check

  • if the head intersects with any of the other positions.

  • So the head, as we know, is...

  • Well, it's this.

  • This is a little bit weird, what I'm doing.

  • That's the last spot and now I can say,

  • for let I equals zero.

  • I is less than this.body.length minus one.

  • I don't want to check the head against itself.

  • I plus plus.

  • I'm going to say let

  • part equal this.body index I.

  • If part

  • index...

  • If part.x equals X

  • and

  • part.y equals Y,

  • then return true.

  • The game is over or

  • if X is greater than

  • what was it, W?

  • Minus one?

  • Or if it's gone off the screen or X is less than zero,

  • Or Y is greater than

  • H minus one,

  • or Y is less than zero, then also return true.

  • We should probably check that first.

  • 'Cause if you're off the edge, I don't need to check...

  • I don't need to check any of the body parts.

  • (deep inhale)

  • Ah, oh but I need to first get the X and Y values.

  • So I'm doing something a little weird

  • but sometimes I'm using the vector

  • and I'm saying pause that X, pause that Y,

  • as soon as I'm pulling out the X and Y from the vector.

  • And then at the end, I'm going to say, return false.

  • So let's see if now, I can get endGame to work.

  • So in here, I'm going to say, also now at the end,

  • if snake.endgame,

  • I'm just going to say print.

  • Print end game

  • and I'm going to say background

  • 255, zero, zero,

  • and noLoop so I'm just going to completely shut down

  • the P5 sketch if the game ends.

  • So this is not necessarily what you want to do for

  • like interaction design but I'm just testing the feature.

  • So the first thing I'm going to do is just

  • try to go off the edge.

  • So I'm going to go off the bottom.

  • Yeah, okay so that works,

  • so going off the edge, at least the bottom.

  • I should probably test the other edges.

  • Oh, what just happened there?

  • And I took my auto refresh off.

  • I'm going to put that on.

  • So if I go off the top, ooh, that didn't work.

  • I probably had a mistake somewhere in there.

  • If

  • oh, Y, this should be Y.

  • Woops, that was a mistake.

  • So (groans),

  • all right hopefully, that fixed that.

  • I'm going to...

  • And now what I need to do,

  • so one thing I need to do, just to be able to test better,

  • is I'm going to add something,

  • I'm going to add the mousePressed function

  • And I'm going to say this, snake.grow.

  • So anytime I click the mouse, I'm going to grow the snake

  • so I could do it, sort of test this feature.

  • Oh, woops, shoot.

  • Oh and you know what?

  • I should set the snake in the middle.

  • So the snake's location should probably be,

  • initially, W divided by two

  • and H divided by two

  • and I've got to keep everything an integer.

  • So I've got to put floor in here,

  • just in case.

  • All right.

  • So now, let me...

  • Whoa, why did that...

  • Oh.

  • Oh because

  • when I grow,

  • the head becomes the same location

  • as the other part of the body.

  • And then I check to see if the game is over.

  • Shouldn't it fix it with...

  • Oh but if it's not moving...

  • So I got to move it first.

  • I mean this should be okay (chuckles).

  • No because if I click,

  • I have to get focused.

  • Ah (deep sigh).

  • This is like a silly debugging thing.

  • So what I'm going to do is I'm going to have it grow

  • with the space bar, not mousePressed.

  • Else if key equals space.

  • I'm just trying to do this to debug it

  • and so I can do whatever I want.

  • And I click over here and I move it,

  • so I'm going to make it longer.

  • So now let's see if it dies, yep.

  • Okay, great (loud clap).

  • So (bell dings) I think I finished this game.

  • Really, what I want to do is come up with an end screen

  • or restart the game or have some sort of score.

  • Let's see, before I go, how long I can play it

  • before I die.

  • And oh, let me just show you something.

  • If I go, I'm going to hit save.

  • If I go under...

  • This is a feature of the web editor.

  • I'm going to go file share,

  • I'm going to go here and I'm going to grab this full screen URL,

  • I'm going to grab it, I'm going to open a new tab,

  • and now it's just the game.

  • I'm going to make it bigger for fun times.

  • I'm going to click it here and ready?

  • I'm going to play the game.

  • Goodbye, make your own version, look for the link,

  • sign up for a P5 web editor account,

  • hit duplicate, make your own version,

  • share it in the comments.

  • There will be a codingtrain.com page,

  • which you could also share it.

  • This is much too easy, I'm going to be here forever.

  • I'm going to look at the...

  • Well, this is working (chuckles).

  • I made the game.

  • I can go home now.

  • Let's just see how long this goes for.

  • (yells) Okay, I died.

  • I don't know why I died.

  • Oh, I hit backwards.

  • (bell dings)

  • (buzzer buzzes)

  • So good thing I hit backwards (trumpet fare)

  • the game is over.

  • Thank you, thank you.

  • So that might be a bug that I want to fix.

  • So that actually, if I hit back...

  • But I guess you shouldn't lose the game

  • if you hit backwards.

  • I don't know.

  • You know, you can make the design more interesting,

  • you can do all sorts of things.

  • You can now make your own version of the snake game

  • in P5, in the web editor, instantly share it.

  • Thank you to the The Processing Foundation,

  • Cassie Tarakajin,

  • all the people who made contributions to the P5 web editor,

  • and all the people who have worked on P5JS over the years.

  • I'm so excited to be able to make tutorials

  • and coding challenges with this.

  • I'll still use my other workflow and I will use processing

  • but I hope you enjoyed this video

  • and I will see you (train horn) next time on Coding Train.

  • (upbeat electronic music)

(train horn)

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A2 初級

編碼挑戰#115:蛇遊戲重裝版 (Coding Challenge #115: Snake Game Redux)

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    林宜悉 發佈於 2021 年 01 月 14 日
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