Let’s dive back into your video game project! Last time, you learned how to make the target and danger sprites move across the screen. But there was a small problem: once they left the screen, they never came back. Today, we’ll learn how to use something called a “boolean” to make them reappear and keep moving across the screen over and over again.
A boolean is a special type of data that can only be true or false. It’s like a simple yes or no answer. In video games, booleans can help us decide what should happen next. For example, if a sprite goes off the screen, a boolean can help us figure out if it needs to come back.
In a previous lesson, you learned how to keep Sam the bat from flying out of his backyard. You did this by using booleans to check if he was “safe left” or “safe right.” Now, we’re going to use the same idea in your video game.
Every time your target and danger sprites move, the game engine checks their position using their x-coordinate. If a sprite goes off the screen, the boolean will return false. When this happens, the game engine will automatically reset the sprite to the opposite side of the screen, just like you did with Sam the bat.
Here’s what you need to do:
First, make sure you have functions that check if the sprites are safe on the left and right sides of the screen. These functions will use booleans to return true if the sprite is still on the screen and false if it has gone off.
Next, combine these functions into an on-screen function. This function will use the results from the safe left and safe right functions to decide if the sprite should be reset to the opposite side.
By following these steps, you’ll be able to make your sprites move back and forth across the screen endlessly, making your game more dynamic and fun!
Now, go ahead and try it out in your game. Have fun coding!
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Imagine you’re on a treasure hunt! Create a simple map on paper with different paths. Use booleans to decide if a path is safe or not. As you move along the paths, mark them as true (safe) or false (unsafe). Can you find the treasure using booleans?
Design a small game using paper cutouts of sprites. Move them across a drawn screen. Use a coin flip to decide if they stay on the screen or reset to the other side. Heads means true (stay), and tails means false (reset). See how long your sprites can stay on the screen!
Write a short story where the main character makes decisions based on booleans. For example, if the character finds a key, the boolean is true, and they can open a door. If not, it’s false, and they must find another way. Share your story with the class!
Create a simple quiz using booleans. Write questions that can be answered with true or false. For example, “Is the sky blue?” Have your classmates take the quiz and see who gets the most correct answers!
Draw a picture using a grid. Use booleans to decide which squares to color. For example, if a square is even-numbered, color it if the boolean is true. If it’s odd-numbered, leave it blank if the boolean is false. Create a unique piece of art!
Here’s a sanitized version of the transcript:
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Let’s take another look at your game. Last time, you animated the target and danger sprites to move across the screen. However, when they left the screen, they never came back. We’re going to use a boolean to bring them back to the screen so they move across the screen repeatedly.
In the last stage, you learned how to keep Sam the bat from leaving his backyard by using a boolean to check if he was safe left and safe right. Now, you’re going to add the same functionality to your video game. Each time your target and danger move, the video game engine will send their x-coordinate to the on-screen function. If a screen ever returns false, that means the sprite has gone off the screen, and the engine will take care of resetting it to the opposite side, just like you did with Sam.
You’ll want to first complete the safe left and safe right functions before combining them both in the on-screen function.
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This version removes any informal language and clarifies the instructions while maintaining the original meaning.
Boolean – A data type that can only have two values: true or false – In coding, we use a boolean to check if a condition is true or false.
Sprite – A graphic or image that can be moved around on the screen in a game or animation – The sprite of the character jumped over the obstacle in the game.
Screen – The display area of a computer or device where images and information are shown – The game looked amazing on the big screen of the computer.
Function – A set of instructions in a program that performs a specific task – We wrote a function to make the character jump when we press the spacebar.
Safe – Free from harm or risk, especially in the context of using technology responsibly – It’s important to keep your passwords safe when using the internet.
Move – To change the position of an object on the screen – We used the arrow keys to move the sprite across the screen.
True – A boolean value indicating that a condition is correct or valid – If the statement is true, the program will display a message.
False – A boolean value indicating that a condition is incorrect or not valid – The program will not run the code if the condition is false.
Game – An interactive program designed for entertainment or education – We created a simple game where you catch falling stars with a basket.
Coordinate – A set of values that show an exact position on a screen or grid – The sprite moved to the coordinate (5, 10) on the grid.
