galdr is an ancient form of sung incantation, intended to have magical effects. Or in more practical
terms, Galdr is an implementation of the entity–component–system (ECS) architectural pattern. Elements in a
world are entities and consist of a unique id and a set of components that are processed by systems. Behaviour of
an entity is changed by adding, updating and removing components. This architecture is typically used in games and
is often used to support data-oriented design techniques.
A Component instance is a passive data container that can be attached to an Entity instance. A typical
Component is a fine-grain data element where all the fields are used to achieve a single logical function.
i.e. A Component may be Position, Velocity, Body, CameraTransform, Health, Sprite etc.
A System is responsible for updating the Component instances attached to Entity instances. A system typically
selects the Entity instances to process based on the set of Component instances. i.e. A RenderSystem may
read the Position and Spite components to render the entity on the screen, a PhysicsSystem may read the Body,
Position and Velocity components and update the Position component etc. It should be noted that in Galdr, the
term SubSystem is used instead of System to avoid a name collision with the java.lang.System class.
The tool is released to Maven Central and can be downloaded using normal dependency download mechanisms. The Maven dependency is:
<dependency>
<groupId>org.realityforge.galdr</groupId>
<artifactId>galdr</artifactId>
<version>0.05</version>
</dependency>The project was released as open source so others could benefit from the project. We are thankful for any contributions from the community. A Code of Conduct has been put in place and a Contributing document is under development.
The project is licensed under Apache License, Version 2.0.