Documentation

API Reference

game-engine

classes

Class: Engine

The engine that handles updating the various entity sub-systems.

Constructors

constructor

• new Engine(config?): Engine

Create a new entity engine.

Parameters

Name	Type
`config?`	`EngineConfig`

Returns

Engine

Properties

nextId

• Private nextId: number

systems

• Private systems: System<unknown>[]

timeRemainder

• Private timeRemainder: number

timeStep

• Private timeStep: number

Methods

addEntity

▸ addEntity(): string

Create a new entity with an unique id.

Returns

string

addSystem

▸ addSystem<SystemT>(system): void

Add a new sub-system.

Type parameters

Name	Type
`SystemT`	extends `System`<`unknown`>

Parameters

Name	Type	Description
`system`	`SystemT`	The system to add

Returns

void

destroy

▸ destroy(): void

Call destroy for all sub-systems and remove them from the engine.

Returns

void

getSystem

▸ getSystem<SystemT>(type): undefined | SystemT

Get a sub-system by type.

Type parameters

Name	Type
`SystemT`	extends `System`<`unknown`>

Parameters

Name	Type	Description
`type`	`Type`<`SystemT`>	The type of the system

Returns

undefined | SystemT

getTimeRemainder

▸ getTimeRemainder(): number

Get the amount of time that has elapsed since the last time step that hasn’t yet warranted a new step update. This is always smaller than the time step.

Returns

number

getTimeStep

▸ getTimeStep(): number

Get the engine’s fixed time step.

Returns

number

removeEntity

▸ removeEntity(entity): void

Remove an entity from the engine, ie. remove aspects bound to the entity from all systems.

Parameters

Name	Type	Description
`entity`	`string`	The entity to remove

Returns

void

requireSystem

▸ requireSystem<SystemT>(type): SystemT

Get a sub-system by type. If the system is not found an exception is thrown.

Type parameters

Name	Type
`SystemT`	extends `System`<`unknown`>

Parameters

Name	Type	Description
`type`	`Type`<`SystemT`>	The type of the system

Returns

SystemT

update

▸ update(dt): void

Update all sub-systems. Every frame the engine calls updates in the following order for each system:

beginFrame(dt, engine, steps) is called in the beginning of the frame with dt being the total time elapsed since the last frame and steps being the total step count for the frame.
step(dt, engine, step, steps) is called n times each frame with dt being the engine’s fixed timestep. The step is the zero-based step counter for this frame and steps is the total number of steps for the frame. Note that the total time for the steps does not necessarily equal the dt of a single frame as the remainder is saved over for the next frame.
endFrame(dt, engine, steps) is called in the end of the frame with dt being the total time elapsed since the last frame and steps being the total step count for the frame.

Each of these updates is called for every sub-system before moving on to the next update, for example beginFrame is called for every sub-system before any of the step updates happen.

Parameters

Name	Type	Description
`dt`	`number`	Frame time in seconds

Returns

void