oak

package module
v1.2.0 Latest Latest
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 Go to latest Published: Aug 5, 2017 License: Apache-2.0 Imports: 33 Imported by: 0

README

Oak

A pure Go game engine

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Installation

go get -u github.com/oakmound/oak/...

On linux, for audio, see klangsynthese for audio installation requirements

Usage

This is an example of the most basic oak program:

oak.AddScene("firstScene",
    // Initialization function
    func(prevScene string, inData interface{}) {}, 
    // Loop to continue or stop current scene
    func()bool{return true}, 
    // Exit to transition to next scene
    func()(nextScene string, result *oak.SceneResult){return "firstScene", nil}) 
oak.Init("firstScene")

See the examples folder for longer demos.

Motivation

The initial version of oak was made to support Oakmound Studio's game, Agent Blue and was developed in parallel. Oak supports Windows with no dependencies and Linux with limited audio dependencies. We hope that users will be able to make great pure Go games with oak and welcome improvements.

Because Oak wants to have as few dependencies as possible, Oak does not use OpenGL or GLFW. We're open to adding support for these in the future for performance gains, but we always want an alternative that requires zero or near-zero dependencies. (We are very sad about the linux audio dependency and are considering writing an audio driver just to get rid of it.)

Features

  1. Window Rendering
    • Windows and key events through shiny
    • Logical frame rate distinct from Draw rate
  2. Image Management
    • render.Renderable interface
    • TileSheet Batch Loading
    • Manipulation
      • render.Modifiable interface
      • Built in Shaping, Coloring, Shading, ...
      • Some built ins via gift
      • extensible Modification syntax func(image.Image) *image.RGBA
      • Copying
    • Built in Renderable types
      • Sprite
      • Sheet Animation
      • Sequence, Compound, Composite
      • History-tracking Reverting
    • Primarily 2D
  3. Particle System
  4. Mouse Handling
    • Click Collision
    • MouseEnter / MouseExit reaction events
    • Drag Handling
  5. Audio Support
    • From klangsynthese
    • Batch Loading
    • Positional filters to pan and scale audio based on a listening position
  6. Collision
    • Collision R-Tree from rtreego
    • 2D Raycasting
    • Collision Spaces
      • Attachable to Objects
      • Auto React to collisions through events
      • OnHit bindings func(s1,s2 *collision.Space)
      • Start/Stop collision with targeted objects
  7. Physics System
    • Vectors
      • Attachable to Objects / Renderables
      • Momentum
      • Friction
      • Force / Pushing
  8. Event Handler, Bus
    • PubSub system
    • event.CID can Bind(fn,eventName) and selectively Trigger(eventName) events
    • GlobalBind and event.Trigger for entity-independent
  9. Timing utilities
    • Smoothed draw rate, frame rate tracking
    • FPS conversion to time.Duration
    • Manipulatable time.Ticker to readily change frame rate
  10. Shaping
    • Shapes from func(x float64) (y float64) equations
    • Shapes from func(x,y,w,h int) bool containment
    • Convert shapes into:
      • Containment checks
      • Outlines
      • 2D arrays
  11. Custom Console Commands
  12. Logging
    • Controlled by config files
    • Filterable by string, debug level

Package-specific Usage

... Pending! See examples or godoc!

Documentation

Overview

Package oak is a game engine. It provides scene control, control over windows and what is drawn to them, propagates regular events to evaluate game logic, and so on.

Index

Constants

View Source 
const (
	// DefaultSeed is a key int64 sent in to SeedRNG
	// used to indicate that the seed function should just
	// do the default operation for seeding, using the current
	// time.
	DefaultSeed int64 = iota
)

Variables

View Source 
var (

	// ScreenWidth is the width of the screen
	ScreenWidth int
	// ScreenHeight is the height of the screen
	ScreenHeight int

	// FrameRate is the current logical frame rate.
	// Changing this won't directly effect frame rate, that
	// requires changing the LogicTicker, but it will take
	// effect next scene
	FrameRate int

	// DrawFrameRate is the unused equivalent to FrameRate
	DrawFrameRate int

	// CurrentScene is the scene currently running in oak
	CurrentScene string
)
View Source 
var (

	// DrawTicker is an unused parallel to LogicTicker to set the draw framerate
	DrawTicker *timing.DynamicTicker
)
View Source 
var (

	// LoadingR is a renderable that is displayed during loading screens.
	LoadingR render.Renderable
)
View Source 
var (
	// LogicTicker is exposed so that games can manually change the speed
	// at which EnterFrame events are produced
	LogicTicker *timing.DynamicTicker
)
View Source 
var (
	// ViewPos represents the point in the world which the viewport is anchored at.
	ViewPos = image.Point{}
)

Functions

func AddCommand 

func AddCommand(s string, fn func([]string))

AddCommand adds a console command to call fn when 'c <s> <args>' is input to the console

func AddScene 

func AddScene(name string, start SceneStart, loop SceneUpdate, end SceneEnd) error

AddScene adds a scene with the given name and functions to the scene map

func BindKey 

func BindKey(key string, binding string)

BindKey binds a name to be triggered when this key is triggered

func ChangeWindow 

func ChangeWindow(width, height int)

ChangeWindow sets the width and height of the game window. But it doesn't.

func FramesElapsed 

func FramesElapsed() int

FramesElapsed returns the number of logical frames that have been processed in the current scene. This value is also passed in to all EnterFrame bindings.

func GetKeyBind 

func GetKeyBind(key string) string

GetKeyBind returns either whatever name has been bound to a key or the key if nothing has been bound to it.

func GetScreen 

func GetScreen() *image.RGBA

GetScreen returns the current screen as an rgba buffer

func Init 

func Init(firstScene string)

Init initializes the oak engine. It spawns off an event loop of several goroutines and loops through scenes after initialization.

func IsDown 

func IsDown(key string) (k bool)

IsDown returns whether a key is held down

func IsHeld 

func IsHeld(key string) (k bool, d time.Duration)

IsHeld returns whether a key is held down, and for how long

func LoadConf 

func LoadConf(filePath string) error

LoadConf loads a config file, that could exist inside oak's binary data storage (see fileutil), to SetupConfig

func LoadConfData added in v1.2.0 

func LoadConfData(r io.Reader) error

LoadConfData takes in an io.Reader and decodes it to SetupConfig

func SeedRNG 

func SeedRNG(inSeed int64)

SeedRNG seeds go's random number generator and logs the seed set to file.

func SetBinaryPayload 

func SetBinaryPayload(payloadFn func(string) ([]byte, error), dirFn func(string) ([]string, error))

SetBinaryPayload just sets some public fields on packages that require access to binary functions as alternatives to os file functions. This is no longer necessary, as a single package uses these now.

func SetLang 

func SetLang(s string)

SetLang parses a string as a language

func SetScreen 

func SetScreen(x, y int)

SetScreen sends a signal to the draw loop to set the viewport to be at x,y

func SetViewportBounds 

func SetViewportBounds(x1, y1, x2, y2 int)

SetViewportBounds sets the minimum and maximum position of the viewport, including screen dimensions

func TransitionFade 

func TransitionFade(rate float32, frames int) func(*image.RGBA, int) bool

TransitionFade is a scene transition that fades to black at a given rate for a total of frames frames

Types

type Assets 

type Assets struct {
	AssetPath string `json:"assetPath"`
	AudioPath string `json:"audioPath"`
	ImagePath string `json:"imagePath"`
	FontPath  string `json:"fontPath"`
}

Assets is a json type storing paths to different asset folders

type Config added in v1.0.3 

type Config struct {
	Assets         Assets `json:"assets"`
	Debug          Debug  `json:"debug"`
	Screen         Screen `json:"screen"`
	Font           Font   `json:"font"`
	FrameRate      int    `json:"frameRate"`
	DrawFrameRate  int    `json:"drawFrameRate"`
	Language       string `json:"language"`
	Title          string `json:"title"`
	BatchLoad      bool   `json:"batchLoad"`
	GestureSupport bool   `json:"gestureSupport"`
	DisableKeyhold bool   `json:"disableKeyHold"`
}

Config stores initialization settings for oak. 

var (
	// SetupConfig is the config struct read from at initialization time
	// when oak starts. When oak.Init() is called, the variables behind
	// SetupConfig are passed to their appropriate places in the engine, and
	// afterword the variable is unused.
	SetupConfig Config
)

type Debug 

type Debug struct {
	Filter string `json:"filter"`
	Level  string `json:"level"`
}

Debug is a json type storing the starting debug filter and level

type Font 

type Font struct {
	Hinting string  `json:"hinting"`
	Size    float64 `json:"size"`
	DPI     float64 `json:"dpi"`
	File    string  `json:"file"`
	Color   string  `json:"color"`
}

Font is a json type storing the default font settings

type Language 

type Language int

Language is hypothetically something games might care about in their text 

const (
	ENGLISH Language = iota
	GERMAN
)

Lang enumerator 

var (
	// Lang is the current langugae
	Lang Language
)

type Scene 

type Scene struct {
	// contains filtered or unexported fields
}

A Scene is a set of functions defining what needs to happen when a scene starts, loops, and ends.

func GetScene 

func GetScene(s string) *Scene

GetScene returns the scene struct with the given name

type SceneEnd 

type SceneEnd func() (string, *SceneResult)

SceneEnd is a function returning the next scene and a SceneResult

type SceneResult 

type SceneResult struct {
	NextSceneInput interface{}
	Transition     transitionFunction
}

A SceneResult is a set of options for what should be passed into the next scene and how the next scene should be transitioned to.

type SceneStart 

type SceneStart func(prevScene string, data interface{})

SceneStart is a function taking in a previous scene and a payload of data from the previous scene's end

type SceneUpdate 

type SceneUpdate func() bool

SceneUpdate is a function that returns whether or not the current scene should continue to loop.

type Screen 

type Screen struct {
	Height int `json:"height"`
	Width  int `json:"width"`
	Scale  int `json:"scale"`
}

Screen is a json type storing the starting screen width and height

Source Files

View all Source files

Directories

Path Synopsis
alg
Package alg stores useful algorithms and math functions
 Package alg stores useful algorithms and math functions
intgeom
Package intgeom stores primitives for integer geometry
 Package intgeom stores primitives for integer geometry
Package audio provides audio types, font types for filtering audio reactively, and channels to allow constant audio play signals to be restricted to play at variable frequencies.
 Package audio provides audio types, font types for filtering audio reactively, and channels to allow constant audio play signals to be restricted to play at variable frequencies.
Package collision provides collision tree and space structures, raycasting utilities and hit detection functions on spaces.
 Package collision provides collision tree and space structures, raycasting utilities and hit detection functions on spaces.
Package dlog provides logging functions with caller file and line information, logging levels and level and text filters.
 Package dlog provides logging functions with caller file and line information, logging levels and level and text filters.
Package entities stores useful object and entity types, such as positions and renderables, collision spaces and renderables, and delta / speed vectors built into the above types.
 Package entities stores useful object and entity types, such as positions and renderables, collision spaces and renderables, and delta / speed vectors built into the above types.
Package event propagates events through entities with given caller IDs.
 Package event propagates events through entities with given caller IDs.
examples
flappyBird
pong
Package fileutil provides functionality to subvert os and ioutil calls when needed for particular operating systems (js) or runtimes (asset data packaged into a binary)
 Package fileutil provides functionality to subvert os and ioutil calls when needed for particular operating systems (js) or runtimes (asset data packaged into a binary)
Package mouse handles the propagation of mouse events though clickable regions.
 Package mouse handles the propagation of mouse events though clickable regions.
Package oakerr stores errors returned throughout oak.
 Package oakerr stores errors returned throughout oak.
Package physics provides vector types and operations to perform math and simple physics on those types.
 Package physics provides vector types and operations to perform math and simple physics on those types.
Package render provides several types of renderable entities which are used throughout the code base In addition to entities the package also provides utilities to load images from files and load images from parts of files (subsprites such as is used in sprite sheets) as well as draw them.
 Package render provides several types of renderable entities which are used throughout the code base In addition to entities the package also provides utilities to load images from files and load images from parts of files (subsprites such as is used in sprite sheets) as well as draw them.
particle
Package particle provides options for generating renderable particle sources.
 Package particle provides options for generating renderable particle sources.
Package shape provides types to satisfy the Shape interface, which allows for containment and outline checks on two dimensional shapes.
 Package shape provides types to satisfy the Shape interface, which allows for containment and outline checks on two dimensional shapes.
Package timing provides utilities for time
 Package timing provides utilities for time

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