engine

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Version: v0.2.0 Latest Latest
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Published: Aug 19, 2021 License: BSD-2-Clause

README

G3N Banner

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G3N - Go 3D Game Engine

G3N (pronounced "gen") is an OpenGL 3D Game Engine written in Go. It can be used to write cross-platform Go applications that show rich and dynamic 3D representations - not just games. A basic integrated GUI framework is provided, and 3D spatial audio is supported through OpenAL.

To see G3N in action try the G3N demo or the Gokoban award winning game.

G3ND In Action

Highlighted Projects Using G3N

Dependencies

Go 1.8+ is required. The engine also requires the system to have an OpenGL driver and a GCC-compatible C compiler.

On Unix-based systems the engine depends on some C libraries that can be installed using the appropriate distribution package manager. See below for OS specific requirements.

Ubuntu/Debian-like

$ sudo apt-get install xorg-dev libgl1-mesa-dev libopenal1 libopenal-dev libvorbis0a libvorbis-dev libvorbisfile3

Fedora

$ sudo dnf -y install xorg-x11-proto-devel mesa-libGL mesa-libGL-devel openal-soft openal-soft-devel libvorbis libvorbis-devel glfw-devel libXi-devel

CentOS 7

Enable the EPEL repository:

$ sudo yum -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

Then install the same packages as for Fedora - remember to use yum instead of dnf for the package installation command.

Windows

We tested the Windows build using the mingw-w64 toolchain (you can download this file in particular).

The necessary audio DLLs are supplied and need to be added to your PATH. If you would like to build the DLLs yourself you can find the libraries' source code and build instructions here.

macOS

Install the development files of OpenAL and Vorbis using Homebrew:

brew install libvorbis openal-soft

Installation

The following set of commands will download and install the engine along with all its Go dependencies:

git clone https://github.com/g3n/engine g3n-engine
cd g3n-engine
go install ./...

Features

  • Cross-platform: Windows, Linux, and macOS. (WebAssembly is 90% complete!)
  • Integrated GUI (graphical user interface) with many widgets
  • Hierarchical scene graph - nodes can contain other nodes
  • 3D spatial audio via OpenAL (.wav, .ogg)
  • Real-time lighting: ambient, directional, point, and spot lights
  • Physically-based rendering: fresnel reflectance, geometric occlusion, microfacet distribution
  • Model loaders: glTF (.gltf, .glb), Wavefront OBJ (.obj), and COLLADA (.dae)
  • Geometry generators: box, sphere, cylinder, torus, etc...
  • Geometries support morph targets and multimaterials
  • Support for animated sprites based on sprite sheets
  • Perspective and orthographic cameras
  • Text image generation and support for TrueType fonts
  • Image textures can be loaded from GIF, PNG or JPEG files
  • Animation framework for position, rotation, and scale of objects
  • Support for user-created GLSL shaders: vertex, fragment, and geometry shaders
  • Integrated basic physics engine (experimental/incomplete)
  • Support for HiDPI displays

G3N Banner

Hello G3N

The code below is a basic "hello world" application (hellog3n) that shows a blue torus and a button that when clicked makes the torus red:

package main

import (
	"github.com/g3n/engine/app"
	"github.com/g3n/engine/camera"
	"github.com/g3n/engine/core"
	"github.com/g3n/engine/geometry"
	"github.com/g3n/engine/gls"
	"github.com/g3n/engine/graphic"
	"github.com/g3n/engine/gui"
	"github.com/g3n/engine/light"
	"github.com/g3n/engine/material"
	"github.com/g3n/engine/math32"
	"github.com/g3n/engine/renderer"
	"github.com/g3n/engine/util/helper"
	"github.com/g3n/engine/window"
	"time"
)

func main() {

	// Create application and scene
	a := app.App()
	scene := core.NewNode()

	// Set the scene to be managed by the gui manager
	gui.Manager().Set(scene)

	// Create perspective camera
	cam := camera.New(1)
	cam.SetPosition(0, 0, 3)
	scene.Add(cam)

	// Set up orbit control for the camera
	camera.NewOrbitControl(cam)

	// Set up callback to update viewport and camera aspect ratio when the window is resized
	onResize := func(evname string, ev interface{}) {
		// Get framebuffer size and update viewport accordingly
		width, height := a.GetSize()
		a.Gls().Viewport(0, 0, int32(width), int32(height))
		// Update the camera's aspect ratio
		cam.SetAspect(float32(width) / float32(height))
	}
	a.Subscribe(window.OnWindowSize, onResize)
	onResize("", nil)

	// Create a blue torus and add it to the scene
	geom := geometry.NewTorus(1, .4, 12, 32, math32.Pi*2)
	mat := material.NewStandard(math32.NewColor("DarkBlue"))
	mesh := graphic.NewMesh(geom, mat)
	scene.Add(mesh)

	// Create and add a button to the scene
	btn := gui.NewButton("Make Red")
	btn.SetPosition(100, 40)
	btn.SetSize(40, 40)
	btn.Subscribe(gui.OnClick, func(name string, ev interface{}) {
		mat.SetColor(math32.NewColor("DarkRed"))
	})
	scene.Add(btn)

	// Create and add lights to the scene
	scene.Add(light.NewAmbient(&math32.Color{1.0, 1.0, 1.0}, 0.8))
	pointLight := light.NewPoint(&math32.Color{1, 1, 1}, 5.0)
	pointLight.SetPosition(1, 0, 2)
	scene.Add(pointLight)

	// Create and add an axis helper to the scene
	scene.Add(helper.NewAxes(0.5))

	// Set background color to gray
	a.Gls().ClearColor(0.5, 0.5, 0.5, 1.0)

	// Run the application
	a.Run(func(renderer *renderer.Renderer, deltaTime time.Duration) {
		a.Gls().Clear(gls.DEPTH_BUFFER_BIT | gls.STENCIL_BUFFER_BIT | gls.COLOR_BUFFER_BIT)
		renderer.Render(scene, cam)
	})
}

hellog3n Screenshot

You can download and install hellog3n via:

go get -u github.com/g3n/demos/hellog3n

For more complex demos please see the G3N demo program.

Documentation

The complete engine API reference can be found here: GoDoc.

There is also the beginning of a Getting Started Guide, and a newly created list of Guides and Tutorials:

Along with those, a good way to learn how to use the engine is to see the source code of G3ND - the G3N demo.

Contributing

If you find a bug or create a new feature you are encouraged to send pull requests!

Community

Join our Discord channel. It's the best way to have your questions answered quickly by the G3N community.

Stargazers over time

Stargazers over time

Directories

Path Synopsis
Package animation
Package animation
Package app implements a cross-platform G3N app.
Package app implements a cross-platform G3N app.
Package audio contains sub packages for binding to external audio libraries and implements a spatial audio player.
Package audio contains sub packages for binding to external audio libraries and implements a spatial audio player.
al
Package al implements the Go bindings of a subset of the functions of the OpenAL C library.
Package al implements the Go bindings of a subset of the functions of the OpenAL C library.
ov
Package ov implements the Go bindings of a subset of the functions of the Ogg Vorbis File C library.
Package ov implements the Go bindings of a subset of the functions of the Ogg Vorbis File C library.
vorbis
Package vorbis implements the Go bindings of a subset (only one function) of the functions of the libvorbis library See API reference at: https://xiph.org/vorbis/doc/libvorbis/reference.html
Package vorbis implements the Go bindings of a subset (only one function) of the functions of the libvorbis library See API reference at: https://xiph.org/vorbis/doc/libvorbis/reference.html
Package camera contains virtual cameras and associated controls.
Package camera contains virtual cameras and associated controls.
Package core implements some basic types used by other packages.
Package core implements some basic types used by other packages.
experimental
collision
Package collision implements collision related algorithms and data structures.
Package collision implements collision related algorithms and data structures.
physics
Package collision implements collision related algorithms and data structures.
Package collision implements collision related algorithms and data structures.
physics/constraint
Package constraint implements physics constraints.
Package constraint implements physics constraints.
physics/equation
Package equation implements SPOOK equations based on the 2007 PhD thesis of Claude Lacoursière titled "Ghosts and Machines: Regularized Variational Methods for Interactive Simulations of Multibodies with Dry Frictional Contacts"
Package equation implements SPOOK equations based on the 2007 PhD thesis of Claude Lacoursière titled "Ghosts and Machines: Regularized Variational Methods for Interactive Simulations of Multibodies with Dry Frictional Contacts"
physics/solver
Package physics implements a basic physics engine.
Package physics implements a basic physics engine.
Package geometry implements several primitive geometry generators.
Package geometry implements several primitive geometry generators.
gls
Package gls implements a loader of OpenGL functions for the platform and a Go binding for selected OpenGL functions.
Package gls implements a loader of OpenGL functions for the platform and a Go binding for selected OpenGL functions.
Package graphic implements scene objects which have a graphic representation.
Package graphic implements scene objects which have a graphic representation.
gui
Package gui implements the GUI infrastructure and several widgets.
Package gui implements the GUI infrastructure and several widgets.
assets
Code generated by go-bindata.
Code generated by go-bindata.
Package light contains common light types which can be add to a 3D scene to illuminate it.
Package light contains common light types which can be add to a 3D scene to illuminate it.
loader
collada
Package collada
Package collada
gltf
Package gltf
Package gltf
obj
Package obj is used to parse the Wavefront OBJ file format (*.obj), including associated materials (*.mtl).
Package obj is used to parse the Wavefront OBJ file format (*.obj), including associated materials (*.mtl).
Package material contains virtual materials which specify the appearance of graphic objects.
Package material contains virtual materials which specify the appearance of graphic objects.
Package math32 implements basic math functions which operate directly on float32 numbers without casting and contains types of common entities used in 3D Graphics such as vectors, matrices, quaternions and others.
Package math32 implements basic math functions which operate directly on float32 numbers without casting and contains types of common entities used in 3D Graphics such as vectors, matrices, quaternions and others.
Package renderer implements the scene renderer.
Package renderer implements the scene renderer.
shaders
Package shaders contains the several shaders used by the engine
Package shaders contains the several shaders used by the engine
Package text implements text font support.
Package text implements text font support.
Package texture contains several types of textures which can be added to materials.
Package texture contains several types of textures which can be added to materials.
tools
g3nshaders
g3nshaders reads shaders files with ".glsl" extensions and generates a Go file containing strings with the content of these files.
g3nshaders reads shaders files with ".glsl" extensions and generates a Go file containing strings with the content of these files.
logger
Package logger implements an hierarchical logger used by other packages.
Package logger implements an hierarchical logger used by other packages.
Package window abstracts a platform-specific window.
Package window abstracts a platform-specific window.

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