examples/factory/spawn_manager/example.md

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tags: factory title: Spawn enemies with central management brief: This example shows how to spawn enemy game objects using a factory component and use a central manager to control movement and behavior of all enemies. author: Defold Foundation scripts: ship.script, spawner.script

thumbnail: thumbnail.png

This example shows how to dynamically spawn enemy game objects using a factory component and use a central manager to control movement and behavior of all enemies. The setup consists of three main components: a player ship, enemy spawner, and different enemy types with customizable properties.

Press keys 1, 2, or 3 to spawn different enemy types.

Example collection consists of 2 game objects:

Ship

The red ship at the bottom that automatically moves and shoots. Consists of:

• A Factory component bulletfactory to spawn bullet game objects
• A Script ship that handles automatic movement (ping-pong animation) and bullet spawning every 0.25 seconds
• A Sprite component with the spaceship image

Bullets are simply animated upward and automatically deleted when they reach the top.

Spawner

Controls enemy spawning with keyboard input. Consists of:

• A Factory enemyfactory to spawn enemies with different properties
• A Label example_description with instructions text displayed on top
• A Script spawner that spawns enemies.

The spawner script defines three different enemy types: random, diagonal, and straight. Uses a factory to create enemies and store their ids and properties in a look-up table:

local properties = ENEMY_TYPES[enemy_type]
local id factory.create("#enemyfactory", position)

self.enemies[id] = { ... }

The spawner script handles enemy movement by looping over the list of currently spawned enemies in the update() lifecycle function. It also uses a physics event listener to detect any enemy to bullet collisions. The spawner script also deletes enemy objects and removes them from the look-up table.

Enemy Types

Random Enemy (Key 1):

• Green UFO sprite
• 1 health point
• Random horizontal movement that changes every second
• Speed: 40 horizontal, -100 vertical

Diagonal Enemy (Key 2):

• Red enemy sprite
• 2 health points
• Fixed diagonal movement
• Speed: 120 horizontal, -80 vertical

Straight Enemy (Key 3):

• Blue enemy sprite
• 3 health points
• Straight downward movement
• Speed: 0 horizontal, -40 vertical

Combine this example with other movement and physics examples to create a complete shoot'em up game!