Glove

Glove is a framework for making games. It is implemented in Crystal.

Caution! Glove is experimental. Expect many breaking changes. There are no tests. Do not use this for your own projects.

Example code

Here is a trivial example that renders a card (from assets/card.png):

require "glove"

card =
  Glove::Entity.new.tap do |e|
    e << Glove::Components::Texture.new("assets/card.png")
    e << Glove::Components::Transform.new.tap do |t|
      t.width = 140_f32
      t.height = 190_f32
      t.translate_x = 400_f32
      t.translate_y = 300_f32
    end
  end

scene =
  Glove::Scene.new.tap do |scene|
    scene.spaces << Glove::Space.new.tap do |space|
      space.entities << card
    end
  end

game = Glove::EntityApp.new(800, 600, "Inari")
game.clear_color = Glove::Color::WHITE
game.replace_scene(scene)
game.run

Architecture

• Glove::EntityApp is a generic game superclass that provides functionality for handling entities, and everything associated with it. Here is how a typical game would build an instance and run the game:

  game = Glove::EntityApp.new(800, 600, "Inari")
  game.clear_color = Glove::Color::WHITE
  scene = Glove::Scene.new.tap do |scene|
    # … build scene here …
  end
  game.replace_scene(scene)
  game.run

• Glove::Entity is a game object that is visible and/or reacts to user input.

• Glove::Component is a property of an entity. A common component is Glove::Components::Transform, which adds width, height, rotation, scale, … to an entity. Another common component is Glove::Components::Camera, which marks an entity as being a camera, and defines which part of a space (see below) will be rendered, with what rotation, etc.

• Glove::Action defines a change to an entity. It can either be instant (e.g. remove entity) or act over time (e.g. move).

• Glove::Space groups entities in a scene that logically belong together and can interact with each other. Entities in different spaces never interact. For example, one space might contain the game entities, and another space might contain UI elements.

• Glove::Scene describes a scene (such as the main menu, credits, or in-game screen). It contains one or more spaces.

• Glove::System describes logic for making changes to a space. A common system is a physics system, which would calculate velocities and update positions.

There are also a handful of simple data classes:

• Glove::Color
• Glove::Point
• Glove::Quad
• Glove::Rect
• Glove::Size
• Glove::Vector

Acknowledgements

This project started out by playing with crystal-gl by Gustavo Giráldez.