Scratch 3.0 Race Guesser (Full Lesson)

Key Takeaways

alright so in this picture behind me this is the men's 100-meter race okay does anybody want to raise their hand and tell me who this person is who this person is in the yellow who wants to raise their hand and tell me who that yellow shirt person is no well this man his name is called Usain Bolt okay and he is the world's fastest man okay the same both holds two World Records okay so a world record is a year it is a record okay so it means that you have run a certain distance the fastest then anybody in the world has ever run before okay so he runs 200 he holds two World Records one is the 100-meter mins races okay men's men's 100 meters and he ran that distance in nine point five eight seconds okay which is really really really fast okay and then he also holds the 200 men's men's running as well so and he's he is a very very fast man so every four years there is something called the Olympics and then in the Olympics that's where all the country has come together as they send their fastest their strongest the most talented people to come together and do these sporting competitions and one of the races that they do is called the one 100-meter dash okay the 100-meter race goes for exactly a 100 meters so if you if you have an oval in your school usually the oval if you run all around the side of the oval is around about 400 meters okay but if you run just one side of oval just the straight line down one side that is around about 100 meters okay so if you if you want to see how fast you are compared to using bolt and maybe one day when you can go outside and you can try to run 100 meters and ask your mum and dad time you okay see if you can beat the world record which is nine point five eight seconds it is very very fast so if you can be the world record make sure you let okay all right so why are we talking about who's involved it's because today we are going to make a little bit of a racing game okay we're going to make a game where you're going to fire off again you go back and then you're going to watch some characters on the screen race from one side restraint or the other and then you are going to make it so that you never know who is going to win it's going to be slightly randomized but it's still going to be super action-packed okay so first thing we want to do is we're going to change our backdrop so let's go into scratch and then I was talking about a school oval before so let's let's switch our backdrop by going down to the bottom so it's really fast so you move your mouse all the way down to the bottom right hand corner and it says choose a backdrop and choose a backdrop now we click it and then we want some place that looks like a school oval like the back of the school level and then we wanted so that we can race from one side to the other okay so I'm thinking playing field looks really really good okay playing field is going to be good if you want to use a playing field if you want to use a hay field that's also good a field MIT that's also good as well okay so I'm going to use a playing field so now we have our cat who is getting ready to run in the playing field yes a soccer court yes you can you can do a stop the court as well so you can make it so that it looks looks at how do you like alright so we start off with a soccer field and now this time what I want you to do is I want you to do to click twice okay so you see my arrow of my my pointer when I click on when I click on the sprite one it's going to flash up with this cap okay you see how the order of the cap flashes okay that's something really important we're going to make sure you know how to recheck the border all the time okay to check to make sure you have the right thing selected but before we do any coding on the cap we are going to do some code on the backdrop so we haven't done the backdrop before so we click on the backdrop and then you're going to see on the top right corner there's a little version of the backdrop okay because we're going to add some code on the battery okay so after you've clicked on the backdrop then we go into events and then we want when flag clicked when flag click and this is going to be what's going to tell our characters in the middle of the field when it's time to reset the game so make sure you have your flat when flag clicked on the backdrop so you have a picture of the backdrop in the middle here and then inside events we wanted to go broadcast a message but instead of broadcasting message one liked down here you click on this arrow and then you go a new message so you go broadcast instead of message one you get a new message and then this message is reset gang reset game make sure you practice your typing skills as well our ESET is reset and game is G AMG okay after we go reset broadcast reset game we'd drag it onto the flag okay going good so far I don't have any questions that's good if you have a question and I'm in the middle of of saying something then try to hang back and then I will try to answer you as soon as I can all right so now we have the nice and easy part done okay so now we are going to press on the cat see when you press on sprite one you don't have the backdrop in the corner anymore you have two cat in the corner okay now I want you to drag your cat onto the side of the screen just like that okay so drag it pressing the mouse and then pulling it all the way to the side like that that is how we are going to make sure that the cat starts at the start of the screen and then we want to make it so that it starts in this starting area every time it hears the reset broadcast so down here down in events you say when I receive reset game see when I receive reset can you drag that over here okay now when the backdrop says to reset gang and the cat is going to hear it when it says when I receive reset game when I receive reset game I'm going to go to this position so I go to motion at the top I scroll all the way up to the top and then I go go to X Y go to X Y and it's got two fans two numbers in here you just leave those numbers the same you can go to an XY let's make sure that the cat is all the way on the top here why are you dragging so if you if you didn't drag your cat up the top and have a look at those numbers it should be minus a hundred and something and why is around thirty something okay it doesn't have to be absolutely precise but you don't have to enter those numbers if you've already dragged hey alright now we're going to keep rolling casting lots of messages in this game because this game is quite complex ok so now I need an another event when this brain is clicked when this bride is clicked what am I going to do with this cat when I click it I'm going to make it so that we start the game and we start the breaks okay so when this pipe sprite is clicked we're going to broadcast another message so here we have broadcast reset game but we don't want to reset the game again when we click on him we wanted to change the message to a new message and this message is start race okay so you're going to broadcast reset game here but we instead of resell yeah we change it to new message and then we got start race like I said if you're missing any of the lesson if you're struggling to type and catch up then don't worry because I'm going to save this video and then you can watch it for the next week okay so we go start race sta RT space RAC e and then we go okay so in this practically we broadcast start rights and to make it broadcast our race we go broadcast down here and then we click the the arrow and then we get a new message and then you type out star race all right when this sprite is clicked we broadcast start race and now we're going to handle what it does when it does when we do start the race so when we go when I receive reset game we change it too when I receive star race when I receive star ace then I drag when I received start rights over here then we are going to do all our code for running down here okay all right before we add our code for running we're going to add a finish line to our game okay so this is the code for the cat you can see that we have the cat selected we we have the cap on the top left here a top right here and we have these coding blocks okay make sure you 100 when I received reset game we go to this this area XY when this sprite is clicked we broadcast our trace and when I receive star trace that is blank so far okay all right to add the finish line we're going to go to add a sprite so you go choose a sprite and then I want you to type line sides L I and he lying and then this is the red line that we have to choose become the red line but the red line is going sideways we don't don't want it going sideways we want to going up and down so make sure you have the line selected and then you click on direction become the direction and then you drag it drag the arrows so that we rotate it all the way down like that and then we can now drag the line on to the side here balle we have a finish line and we have a cat okay now make sure you have the line you dragged it so that the direction is facing up and down so you click on the line and then you click on direction and then you drag it around by dragging this distillation error okay so now we have the line finish line and then we have a cap all right now we go back to the cap they come back at when I receive start race what do I want the cap to do well what I want the cat to do first is we want to make it go back to this starting position so to go back to the standing position remember we already made it when I receive reset game we go to the standing position so when I start the race I have to broadcast reset game so you're going to events and then your broadcast reset also we don't yes we go broadcast reset game la when I click on this click on the cap where you also go back to the start position ok let me go to the start position now we are going to race we're going to go and give it a forever loop so we go into control and then we give it a forever loop and then in this parabola we wanted to take a step every 0.1 seconds okay so we go wait 0.1 over here so going to control there is a wait something seconds so you change that whatever that number is to 0.1 so the point is the dot on your keyboard so look for a dot on your keyboard so we go wait 0.1 and then we drag it inside the forever loop drag it inside the forever loop and then we are going to go make it take a step forward so we go into motion and then we go change X by 10 but instead of 10 would change it to five change X 5 5 and that's emotion so every 0.1 seconds it's going to move forward by five little points okay you very well so far going nice and slowly so everyone can follow because this class is for seven to nine year olds there's going to be people who are are towards nine years old and there's people come closer to seven years old so some people are going to struggle with typing so that's still not no problem make sure we we follow as close as we can alright so the next part after we have moved our step by five we need to make sure that we stop the race once we reach the end okay once we reach the end we need to be able to stop the race and and and make sure that we don't run anymore okay so this is what we're going to do so we go change X by five and then we're going to go and put an if block inside the forever loop so going to control and then we want to do and if then block say this one here if then z if then and then we drag it so that is just after change X by five you if we are touching the line then we stop the race that's that's the whole idea is we go if we touch the line then we stop the race so we go if and then inside this hexagon we need sensing because that's where we sense if we touch the line sensing there's touching mouse pointer but we don't want touching mouse pointer if you want touching line so touching and then you hit the arrow and then we choose a line and when we put that inside the hexagons if we are touching the line then we're going to broadcast another message to say that the race is over okay but if we're touching the line we go and broadcast another message if you know how to do the broadcast already then you can skip ahead and start doing the broadcast but if the after we touched the line we have to do two things we have to say we're broadcasting that the race is over and then also we're going to have our cat say I won and won the race okay so if we are touching the line we go into events I scroll back to events you can press the yellow button to get yellow blocks together events when that's touching the line we broadcast but instead of broadcasting reset gang we're going to broadcast new message okay we got a broadcast another new message broadcast instead of briefs briefs okay we're broadcasting new message and this new message is race over to tell all the people who are raising that the race is over and then we press okay now it's got broadcast race over is now on the left-hand side here we drag it to inside when it touches the line and then lastly the second thing we need to do where we touch the line is we say that the race is over because we already have a winner and then the second thing is we have to get our cats to show that he's happy so he going to looks well although after looks purple ones and then we go saying i won [Music] or two seconds so you say I won for two seconds and then we drag that onto here broadcast the race is over and then say I won for two seconds you all right so now I'm going to test my my code so when I click on my cap it's going to start running running running across the screen and then it touches the end and then it says I won she's just perfect because that is exactly what we wanted any questions so far if you can is not running and touching the screen touching the end and saying I won then let me know Yolanda you have a question yeah is it working well it just reached it when it reaches line it just keeps on going and screaming i won ah very good so that is a that is correct because there is one broadcast that we haven't handled yet do you know which one we haven't handled it's not hmm that's right so that's the race over broadcast so we are going to do that afterwards so after you um after it runs off the edge then you press the flag again and then it will go back to the stack then we'll we'll handle the UM the base end okay so now to stop the cap from keeping on running off the edge you press the flag again to remove it back to the start and then we're going to continue on without coding okay all right very good everybody's following very well today a very very very impressed okay because this is a very hard bit of code there's a lot of code here so now we are going to handle the broadcast for race over so we're going to go to events great events and then we scroll down to when I receive reset game but instead of when I receive reset game we're going to handle the race over so we're going to handle its change reset game to race over so we click on the arrow and then we go race over so when I receive race over and then we're going to start another new line of code okay so when I receive race over we have to put it on a completely new line over here what are we going to do when we receive race over very very simple we're going to control okay and then I guys stop instead it stopped all but instead of stop all we click on the arrow and we go and stop other scripts in this sprite okay this stop is in control stop instead of supple if we stop all other scripts in this sprite so a script is one of these lines of code okay so this is a script when I receive reset game this is another script this is another script okay so we want when with the race is over just stop everything from from working okay that way we tell this the sprite just stop what you're doing the race is over so make sure we go stop all other scripts in the sprite and then drag it to when I receive race over so now when I stop the race when I click on the cat gotta go run run run run run run and then once it reaches this line it says I won and it's going to stop moving no problem very good Ryan all right so now if before we add more people to the race I want to ask everyone what do you think will happen if I copied more of these cats down down below if I copied this exact cat down below will you be able to what's going to be what's going to happen if we if we copied this cap what's going to happen if we copied this cat a few times yeah you haven't asked anything before what do you think will happen if I copy the cat a few times also I would I would I win hmm that's right so a problem if I copied this cat each time you and that is fantastic you and by the way if I copy this cat then every single cat is going to run at exactly the same speed all right and that's going to be a problem for a racing game because it's not going to be very fun if all the cats are running at the same speed and going to the finish line and everyone wins at the same time right so who wants to have a go on telling me how I can make it so that the cats don't run outside and me don't run at the same speed Kevin what's your change it change the speed change the speed whereabouts do I change the speed you point out which which script here the way thing ah very good so we got the change went by 0.1 seconds here and also we can change this right yeah the x-value excellent excellent work Kevin so Kevin is exactly right because when you're calculating speed like how fast you're going there's two things you can change okay the first thing is to change how fast you are going how much time it takes to go somewhere right so the smaller the time this faster you're going to get someone right the other thing is how much distance you cover each step right so the biggest step that you take the faster you're going to get there as well so there's distance and there's time and both these things you can change to make it go faster or slower okay so for our for our code we're going to try and make it so that instead of going a fixed distance we're going to randomize the distance so that it's not going to go at a fixed length of time all the time so you have to look at the same bolt over here he can go a huge amount of distance with every single step right but he doesn't take that same distance of a step every single step right it's not like a machine where he goes okay I'm gonna take exactly a two meter long step edge to edge time right sometimes it goes a bit further sometimes he goes a bit but mostly he's going for is the fastest man on earth right but a lot of normal people you take a step and it's not necessarily the same as the other step so we're going to make it a little bit random okay so let's have a look at this random all we have to do is change this part here where it says change X by five what we're going to do here now is we're going to randomize it okay so we're going to go into randomizer who wants to tell me how we do random how can we do a randomized aja once they raise their hand and have a guess maybe somebody who has been to one of the one of the trial classes they can tell no that's okay so random is in operators okay I know it's a little bit hard this one random is in operators and for for random I want you to go pick random one to ten but instead of one to ten we want to change it to one to five that way sometimes you'll he'll take a step that is only one one one pixel in distance and sometimes they'll take a step that's five pixels in different distance okay that way we can make it so that sometimes he really goes a little bit further and sometimes he goes a little bit random one two five and then we replace the change in X by five okay now when we click on our cat you're going to notice that sometimes it's going to take bigger steps and sometimes they'll take smaller steps so you press on the cat oh yeah sometimes it takes bigger steps and sometimes it takes smaller steps and you'll notice that that he'll move to the red line a little bit slower than before because before we were making sure he was taking five five a length of five five pixels every single step but now he can take much longer than that sometimes he'll take a step of one pixel instead that means that he's going to move a lot slower than he was going to move we are almost almost ready to run this race okay so I've clicked on the cat again and it is done all the way back and start and then he's going to drown run run run run the way to --eline now we are going to add some animation now to to the cat because there one of the things is that the cat right now is looking like it's frozen right and it's just moving and it's frozen but now we want to make it look like it's moving his arms and legs a little bit so how do we change it so that it moves his arms and legs a little bit we're going to look at his costumes okay so let's have a look at our costumes we have that cat selected I click on costumes and then you'll see there's two costumes already one with the cat like this and the other one with a cap like this though is slightly moving right so we want to make it so that the cat is switching between these costumes over and over and over again okay so let's go back to our code and then who wants to tell me how we make it so that the cat is switching costume how which which which blocks do we use while switching costume Ethan haven't heard you before how are you doing Ethan how do we change looks and then you can see switch costume to cat B or the next costume yeah very good so while you are on while you're on the microphone Ethan where should I put next costume if I want to switch it to the next costume where on my script do you think I should put it maybe I changed Xbox one to five fantastic excellent Ethan well done so if you heard what Ethan said this is his suggestion we go add next costume this block here inside looks we go next costume put it inside change eggs by the random and then we put next costume in directly after it and now when we click on the cat it's going to make a little bit of a hopping motion all the way to the finish line and now it's looking more interesting because the cat is moving is not frozen right how long is he gonna take yeah he says I won okay so now we are going to press the flag make sure you press the flag and don't start the race okay because we're going to now copy all this code on another cat okay but we don't want to spend all that time copying one block after another after another and after another it's like this is the hard way okay we could just go I'd choose a sprite and we can make sure that the cat is selected and then we move all the blocks copy and then copy all the blocks but I want to make it so that we just make it exact copy really quickly how do I do that yeah do you have an idea yes maybe all of them just copy a little bit of them well that's a good good suggestion but unfortunately we need every bit of this code for all our races otherwise they won't be able to to do the race Ethan what's your idea how can we make copy you right-click you right-click on the code and there's a duplicate there's duplicate and you press it and then another chapter excellent Ethan well done so Ethan is right so all you have to do is move your mouse pointer you see in my mouse pointer make sure we have two cat select it down here and then we right-click right-click on this cat and then there's a duplicate button that pops up okay so we need to right-click and then duplicate now I know some people are on there using a trackpad on their on their computer the right-click button is either the Creek on the right corner bottom right corner of your trackpad or if you're using an Apple computer you have to click with two fingers on the trackpad okay make sure you can see this duplicate button pop up on the menu okay if you can't see the duplicate button let me know raise your hand right now all right let me do it okay so we go right click and then we go duplicate now we have a second cat as all the way out but don't oppress a thing don't touch anything on that cat yet because this is really important okay this is really important don't touch the cat yet what we need to do don't touch the cat yet we need to I click on sprite one and then it says go to XY right it says go to XY for when it resets game to minus 189 36 or whatever your numbers are you click on the new sprite sprite - you have to decrease that number okay decrease that number to negative 18 the why number so go to X is we keep it the same but why we change it to minus 84 when resets going okay make sure you do that before we go any further okay but only for that new sprite we go go to XY and we change Y to negative 18 and that's the only difference for this cat compared to the other cap because the other cat is going out whatever whatever disincentive that is what a position that is and why for this pride we want to make it so that it doesn't go to that exact same place right otherwise you won't see your your runners set right now so now we press the flag and now we press on one of the cats and then they're going to start racing and you're gonna see that if you play this race a few times you'll see that it's not always the same cat that wins sometimes it's a cap on the top sometimes it's a cat on the bottom but only the cat that wins because it touches the line will say that one and it stops the race from continuing on