Engine Integration Patterns

graphics.gd projects have a few different options for integrating with the engine.

Caution

you should only import “graphics.gd/startup” from your main Go package

Go

You can ignore the object-oriented nature of the engine entirely and use the startup.Rendering function to wait for rendering to be available, then you can iterate over each frame and use the RenderingServer directly. Choose this option when porting an existing Go application to graphics.gd and when you will be porting existing rendering code to use the RenderingServer.

package main

import "graphics.gd/startup"

func main() {
  frames := startup.Rendering()
  // engine has started, rendering is available
  for frame := range frames {
    // do something each frame
  }
}

MainLoop

Alternatively, implement the MainLoop.Interface and register this with the Engine to replace the default SceneTree.

package main

import (
  "graphics.gd/classdb/MainLoop"
  "graphics.gd/startup"
  "graphics.gd/variant/Float"
)

type MyMainLoop struct{
  MainLoop.Implementation
}

func (m *MyMainLoop) Initialize() {} // do something when the engine starts
func (m *MyMainLoop) Process(delta Float.X) {} // do something each frame
func (m *MyMainLoop) Finalize() {} // do something when the engine shuts down

func main() {
  startup.MainLoop(new(MyMainLoop))
}

SceneTree

Otherwise, leave the default SceneTree main loop implementation in place and pass control to the engine using startup.Scene() which will block until the engine shuts down. Projects setup using the gd command will open the main.tscn by default.

package main

import (
  "graphics.gd/classdb/SceneTree"
  "graphics.gd/classdb/Node"
  "graphics.gd/startup"
)

func main() {
  startup.LoadingScene()     // (optional) wait until the engine is ready to load the scene.
  SceneTree.Add(Node.New()) // (optional) setup the SceneTree, e.g. add nodes
  startup.Scene() // starts up the scene and blocks until the engine shuts down.
}

AsExtension

Want to create extensions that can be redistributed to other Godot engine users? Please note that only a single Go runtime can be active within any OS process, so all Go extensions within a project should be built together into a single shared library.

package main

import (
  "graphics.gd/startup"
)

func main() {
  startup.AsExtension()
}