Layers

The core of the program is an application, which defines the update loop.

The update loop dispatches to several layers, which which are mostly self contained units of logic. The layers get exlusive access to the world, resources, and events and may execute any logic in on_update. They also get exclusive access to self which enables them to both read and modify their own state.

This is useful for games where the main game logic can be contained in one or more layers and store the state without interfering with other layers such as physics.

The layered design allows several high level concepts to work together in unison and separately and allows for logic to be added or removed.

An example would be a game which makes use of a client and server. The binaries can share most of the code, and the client and server can be separated into separate layers which allows the client to use all the same game logic as the server, and vice versa. The server and client layers can also be present at the same time which allows a self hosted client.

The on_update function takes three parameters:

• World
• Resources
• Events

The return type is of anyhow::Result and allows for any error to be propogated.

For a layer to be used it needs to be pushed into the App.

Example Usage

The layer is a trait which must define an on_update function

The following examples shows the basic usage of a layer, as well how to create an application using the layer.

#![allow(unused)]
fn main() {
{{#include ../../../examples/layer.rs}}
}