Code a Fun Space Shooter Game 🚀 | 1. Move & Shoot | Scratch Tutorial

Summary

In this 'Mix It Up Monday' tutorial, Griffpatch takes viewers through the creation of a space-themed game inspired by Asteroids, where players fight back an invasion of 'lemons' with rapid-fire lasers. The tutorial covers the design and movement of the player's spaceship, basic laser shooting mechanics, and how to handle rapidly moving projectiles and clones in Scratch. Special effects like camera shake and explosions are also explored, alongside tips on creating smooth player movement and robust collision handling. The video sets the stage for further game development, with a sneak peek at future episodes featuring the lemon enemies.

Takeaways

• 😀 Lemons are taking over the universe in a game inspired by Asteroids, with rapid-fire laser projectiles.
• 😀 The main focus of the tutorial is on handling fast-moving projectiles, enemies, and robust collision detection.
• 😀 The player sprite is designed by drawing a triangle and adjusting it to face right, followed by centering and rotating for smooth motion.
• 😀 Smooth player movement is achieved by using variables for speed (x and y) and implementing air resistance to slow the player down.
• 😀 Custom blocks like 'move x' and 'move y' help organize code for smoother player controls using keyboard inputs.
• 😀 The player sprite rotates to face the mouse pointer, enabling intuitive movement for a fast-paced game.
• 😀 The laser sprite is created with a custom design involving a rectangle with rounded edges and a lemon yellow outline.
• 😀 Laser projectiles are cloned and move in the direction of the player’s facing position, disappearing when they hit the stage edge.
• 😀 Firing lasers is initially triggered by pressing the space key, but the issue of multiple clones being created is identified and fixed.
• 😀 To solve cloning issues, firing the laser is triggered from the player sprite, and the rate of fire is controlled by a 'fire rate' variable.
• 😀 The tutorial emphasizes the importance of controlling clone creation and improving gameplay with adjustable fire rates to avoid overwhelming the system.

Q & A

Why is it important to rotate the player sprite around its center?

Rotating the player sprite around its center ensures smooth and predictable movement, especially when rotating the ship to face the mouse cursor. This makes the game mechanics feel more natural and allows for more precise control of the player's ship.

What is the purpose of using custom blocks in this tutorial?

Custom blocks help organize the code into smaller, more manageable sections, improving readability and making it easier to troubleshoot and modify later. It also provides clear names for each chunk of code, making the project more understandable for both the creator and others who may revisit it.

Why is 'speed x' and 'speed y' used to control the movement of the player sprite?

'speed x' and 'speed y' represent the player's velocity along the x and y axes, respectively. This allows for smooth and continuous movement, taking into account acceleration and air resistance (slowing down). By adjusting these values, the player ship moves in a fluid and responsive manner.

What causes the issue of clones being created in an exponential manner when pressing the space bar?

The issue arises because the 'create clone' block is placed inside the laser sprite. Each time the space bar is pressed, both the original sprite and any clones also trigger the creation of new clones. This causes a rapid exponential increase in clones, leading to the depletion of available clones and creating performance issues.

How can the laser firing issue be resolved?

To resolve the issue, the laser firing should be triggered from the player sprite, rather than from the laser sprite itself. This ensures that only the player sprite reacts to the space bar press, preventing the creation of unnecessary clones and ensuring the game runs smoothly.

Why is the 'point in direction' block used for firing the laser?

'Point in direction' is used to ensure that the laser moves in the direction the player ship is facing. This allows the laser to follow the player's orientation, whether that is aimed at the mouse cursor or some other target, providing an accurate and responsive firing mechanic.

What does the 'fire rate' variable control in this game?

The 'fire rate' variable controls how quickly the player can shoot lasers. By adjusting this variable, the game can limit the rate of fire, preventing the player from firing an overwhelming number of lasers in a short period, which could unbalance the game.

How does air resistance affect the player’s movement in this tutorial?

Air resistance is simulated by using a factor of 0.9 to slow down the player’s movement over time. This prevents the ship from continuing to accelerate indefinitely and gives a more realistic, controlled movement feel, allowing the player to slow down gradually when no keys are pressed.

What is the significance of the background color being 'almost but not quite black'?

The background color being 'almost but not quite black' creates a visually interesting contrast that helps the player sprite and other elements stand out more clearly on the screen, while still maintaining a space-like aesthetic. It adds to the atmosphere of the game without being too harsh or distracting.

Why is it important to hide the main laser sprite and only use clones for firing?

The main laser sprite is hidden to prevent it from being used directly in the game, as it could lead to errors where clones are not properly deleted. By using only cloned laser sprites, the game ensures that each laser behaves as intended, is visible when fired, and can be deleted when it leaves the stage.