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  • Allison:Hey guys!

  • I was just testing out the game I made.

  • It's super easy to make simple games like this.

  • And, in fact, I'll show you how I made it right now.

  • Let's head on over to www.scratch.mit.edu.

  • We want to create a new project, so lets click on the Create tab.

  • I've already got a product opened, so we're going to switch over here.

  • >> Let's start with a quick tour of the scratch environment.

  • On the bottom left here, we have all the sprites that will

  • be used in our game.

  • For example, we have a monkey, banana, and broccoli.

  • When we click on each sprite you'll notice that the right column will

  • change, to show us that we're working with that specific sprite.

  • Anything we put in this column will control the sprite that's highlighted.

  • Here in the middle, we have our column containing our pallet a puzzle pieces,

  • which we'll use to create our game.

  • At the top, we have the category of puzzle pieces we have to work with.

  • For example, the blue pieces, under the Motion tab, will allow us to

  • control how our sprites move.

  • We'll explore the other categories as we create our game.

  • Finally, on the top left, we have our stage, where we'll

  • actually play our game.

  • Where we can see the effects of our scripts on the sprites.

  • >> So let's get started.

  • In our game, the monkey will try to eat the banana while

  • avoiding the broccoli.

  • The monkey will follow our mouse, and the broccoli and banana will float

  • around the stage randomly.

  • When the monkey gets close to the banana, the banana will actively try

  • to avoid the monkey, just to make things a bit more exciting.

  • >> Let's start by scripting the behavior of our main character, the monkey.

  • To start our script, we'll use the When Green Flag clicked piece from the

  • events category.

  • Here.

  • This will cause all puzzle pieces connected to the button to run when we

  • click the Green Flag, here, at the top right of the stage.

  • We want the monkey to follow the mouse.

  • So we choose the Go To button and select Mouse Pointer, like so.

  • So we're going to try it here.

  • Let's test is and see what happens.

  • >> So it seems like the monkey really only followed the first mouse click.

  • This is because, by default, the Go To block only executes once.

  • To get the monkey to follow the mouse throughout the entire game, we need

  • this block to execute over and over again.

  • Sounds like we need some kind of looping construct.

  • So lets move into Control.

  • Look, let's try this Forever loop.

  • Seems like it works.

  • >> So, next we should think about how the monkey will

  • interact with other sprites.

  • Basically, we need to add logic to our game, such that, the game will end if

  • the monkey touches the banana or the broccoli.

  • And actually use the word "if" when describing the behavior

  • we're trying to create.

  • And conveniently enough, there's a control blocked called If that we use

  • for exactly this purpose.

  • So the diamond shape, right here, on the block, is where we put the

  • condition that we want to check.

  • In this case, we'll check whether the monkey is touching the banana.

  • >> Se we grab the Touching piece from the Sensing category.

  • And choose Banana from the drop down menu.

  • Now we have to tell our sprite what to do when it touches the banana.

  • We want the game to end, and the monkey to say, you've won.

  • So we add in a Say and Stop All piece.

  • We'll change, hello, to, you won.

  • And the time to 0.5.

  • Now, we'll apply the same logic when the monkey is touching the broccoli,

  • except we'll have the monkey say, you lost, instead of, you won.

  • >> Let's test this out and see if it works.

  • Awesome.

  • We've finished scripting the monkey's behavior, but we're not done yet.

  • We still have to tell the broccoli and banana what to do.

  • >> Let's start with the simpler of the two, the broccoli.

  • Which just needs to move randomly.

  • Again, we'll begin with the When Green Flag clicked piece.

  • We need the sprite to be in constant motion, so let's drag

  • out the Forever loop.

  • We'll create a random motion using some motion pieces with a random

  • number generator.

  • >> Alright, let's test this out.

  • Awesome

  • >> OK, now only the banana is left.

  • Let's start off with the same set of pieces as before.

  • So if the monkey gets close, the banana should avoid it.

  • Else, the banana should move randomly.

  • Sounds like a job for this If Else block.

  • In the condition, we will check the bananas distance from the monkey, and

  • then have it avoid accordingly.

  • >> Now, when this condition doesn't apply, the

  • banana should move randomly.

  • So let's just steal our random motion pieces from the broccoli.

  • All we have to do is drag the pieces we want to the banana sprite, and

  • they'll be copied over.

  • >> All done.

  • Let's test it out.

  • Awesome.

  • Everything seems to be working.

  • Now go and make your own games.

  • >> If you need some inspiration check out past projects

  • from CS50 on the website.

  • >> My name is Allison, and this CS50.

  • >> I need to get these set up super quick.

Allison:Hey guys!

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    chuan.me 發佈於 2021 年 01 月 14 日
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