examples/factory/spawn_properties/example.md

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tags: factory title: Spawn enemies with script properties brief: This example shows how to spawn enemy game objects using a factory component with different properties. author: Defold Foundation scripts: ship.script, enemy.script, spawner.script

thumbnail: thumbnail.png

This example shows how to dynamically spawn enemy game objects using a factory component with different properties. 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 factory to create enemies with specific properties:

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

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

Enemy Script Properties

Properties defined in enemy.script control enemy behavior:

• sprite - Which sprite to display
• health_points - How many hits before destruction
• speed - Movement velocity vector
• is_random - Whether to use random movement changes

When enemies have go.property defined in their script, these properties are visible in the Properties pane and can be customized per enemy type.

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