ebiten

README

Ebiten

A dead simple 2D game library for Go

Ebiten is an open source game library for the Go programming language. Ebiten's simple API allows you to quickly and easily develop 2D games that can be deployed across multiple platforms.

• Website (ebiten.org)
• API Reference
• Cheat Sheet

Platforms

• Windows (No Cgo!)
• macOS
• Linux
• FreeBSD
• Android
• iOS
• Web browsers (Chrome, Firefox, Safari and Edge)
  • WebAssembly
  • GopherJS

Note: Gamepads and keyboards are not available on iOS.

For installation on desktops, see the installation instruction.

Features

• 2D Graphics (Geometry/Color matrix transformation, Various composition modes, Offscreen rendering, Fullscreen, Text rendering, Automatic batches, Automatic texture atlas)
• Input (Mouse, Keyboard, Gamepads, Touches)
• Audio (Ogg/Vorbis, MP3, WAV, PCM)

Packages

• ebiten
  • audio
    • mp3
    • vorbis
    • wav
  • ebitenutil
  • inpututil
  • mobile
  • text

Community

Slack

#ebiten channel in Gophers Slack

License

Ebiten is licensed under Apache license version 2.0. See LICENSE file.

Documentation

Overview

Package ebiten provides graphics and input API to develop a 2D game.

You can start the game by calling the function RunGame.

// Game implements ebiten.Game interface.
type Game struct{}

// Update proceeds the game state.
// Update is called every tick (1/60 [s] by default).
func (g *Game) Update(screen *ebiten.Image) error {
    // Write your game's logical update.
    return nil
}

// Draw draws the game screen.
// Draw is called every frame (typically 1/60[s] for 60Hz display).
func (g *Game) Draw(screen *ebiten.Image) {
    // Write your game's rendering.
}

// Layout takes the outside size (e.g., the window size) and returns the (logical) screen size.
// If you don't have to adjust the screen size with the outside size, just return a fixed size.
func (g *Game) Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int) {
    return 320, 240
}

func main() {
    game := &Game{}
    // Sepcify the window size as you like. Here, a doulbed size is specified.
    ebiten.SetWindowSize(640, 480)
    ebiten.SetWindowTitle("Your game's title")
    // Call ebiten.RunGame to start your game loop.
    if err := ebiten.RunGame(game); err != nil {
        log.Fatal(err)
    }
}

In the API document, 'the main thread' means the goroutine in init(), main() and their callees without 'go' statement. It is assured that 'the main thread' runs on the OS main thread. There are some Ebiten functions that must be called on the main thread under some conditions (typically, before ebiten.RunGame is called).

Environment variables

`EBITEN_SCREENSHOT_KEY` environment variable specifies the key to take a screenshot. For example, if you run your game with `EBITEN_SCREENSHOT_KEY=q`, you can take a game screen's screenshot by pressing Q key. This works only on desktops.

`EBITEN_INTERNAL_IMAGES_KEY` environment variable specifies the key to dump all the internal images. This is valid only when the build tag 'ebitendebug' is specified. This works only on desktops.

Build tags

`ebitendebug` outputs a log of graphics commands. This is useful to know what happens in Ebiten. In general, the number of graphics commands affects the performance of your game.

`ebitengl` forces to use OpenGL in any environments.

Index

• Constants
• Variables
• func CurrentFPS() float64
• func CurrentTPS() float64
• func CursorPosition() (x, y int)
• func DeviceScaleFactor() float64
• func GamepadAxis(id int, axis int) float64
• func GamepadAxisNum(id int) int
• func GamepadButtonNum(id int) int
• func GamepadIDs() []int
• func GamepadName(id int) string
• func GamepadSDLID(id int) string
• func InputChars() []rune
• func IsCursorVisible() bool
• func IsDrawingSkipped() bool
• func IsFocused() bool
• func IsFullscreen() bool
• func IsGamepadButtonPressed(id int, button GamepadButton) bool
• func IsKeyPressed(key Key) bool
• func IsMouseButtonPressed(mouseButton MouseButton) bool
• func IsRunnableInBackground() bool
• func IsRunnableOnUnfocused() bool
• func IsRunningSlowly() bool
• func IsScreenClearedEveryFrame() bool
• func IsScreenTransparent() bool
• func IsVsyncEnabled() bool
• func IsWindowDecorated() bool
• func IsWindowFloating() bool
• func IsWindowMaximized() bool
• func IsWindowMinimized() bool
• func IsWindowResizable() bool
• func MaxTPS() int
• func MaximizeWindow()
• func MinimizeWindow()
• func MonitorSize() (int, int)
• func RestoreWindow()
• func Run(f func(*Image) error, width, height int, scale float64, title string) error
• func RunGame(game Game) error
• func RunGameWithoutMainLoop(game Game)
• func ScreenScale() float64
• func ScreenSizeInFullscreen() (int, int)
• func SetCursorMode(mode CursorModeType)
• func SetCursorVisibility(visible bool)
• func SetCursorVisible(visible bool)
• func SetFullscreen(fullscreen bool)
• func SetInitFocused(focused bool)
• func SetMaxTPS(tps int)
• func SetRunnableInBackground(runnableInBackground bool)
• func SetRunnableOnUnfocused(runnableOnUnfocused bool)
• func SetScreenClearedEveryFrame(cleared bool)
• func SetScreenScale(scale float64)
• func SetScreenSize(width, height int)
• func SetScreenTransparent(transparent bool)
• func SetVsyncEnabled(enabled bool)
• func SetWindowDecorated(decorated bool)
• func SetWindowFloating(float bool)
• func SetWindowIcon(iconImages []image.Image)
• func SetWindowPosition(x, y int)
• func SetWindowResizable(resizable bool)
• func SetWindowSize(width, height int)
• func SetWindowTitle(title string)
• func TouchIDs() []int
• func TouchPosition(id int) (int, int)
• func Wheel() (xoff, yoff float64)
• func WindowPosition() (x, y int)
• func WindowSize() (int, int)
• type Address
• type ColorM
  • func Monochrome() ColorM
  • func RotateHue(theta float64) ColorM
  • func ScaleColor(r, g, b, a float64) ColorM
  • func TranslateColor(r, g, b, a float64) ColorM
  • func (c *ColorM) Add(other ColorM)
  • func (c *ColorM) Apply(clr color.Color) color.Color
  • func (c *ColorM) ChangeHSV(hueTheta float64, saturationScale float64, valueScale float64)
  • func (c *ColorM) Concat(other ColorM)
  • func (c *ColorM) Element(i, j int) float64
  • func (c *ColorM) Invert()
  • func (c *ColorM) IsInvertible() bool
  • func (c *ColorM) Reset()
  • func (c *ColorM) RotateHue(theta float64)
  • func (c *ColorM) Scale(r, g, b, a float64)
  • func (c *ColorM) SetElement(i, j int, element float64)
  • func (c *ColorM) String() string
  • func (c *ColorM) Translate(r, g, b, a float64)
• type CompositeMode
• type CursorModeType
  • func CursorMode() CursorModeType
• type DrawImageOptions
• type DrawRectShaderOptions
• type DrawTrianglesOptions
• type DrawTrianglesShaderOptions
• type Filter
• type Game
• type GamepadButton
• type GeoM
  • func RotateGeo(theta float64) GeoM
  • func ScaleGeo(x, y float64) GeoM
  • func TranslateGeo(tx, ty float64) GeoM
  • func (g *GeoM) Add(other GeoM)
  • func (g *GeoM) Apply(x, y float64) (float64, float64)
  • func (g *GeoM) Concat(other GeoM)
  • func (g *GeoM) Element(i, j int) float64
  • func (g *GeoM) Invert()
  • func (g *GeoM) IsInvertible() bool
  • func (g *GeoM) Reset()
  • func (g *GeoM) Rotate(theta float64)
  • func (g *GeoM) Scale(x, y float64)
  • func (g *GeoM) SetElement(i, j int, element float64)
  • func (g *GeoM) Skew(skewX, skewY float64)
  • func (g *GeoM) String() string
  • func (g *GeoM) Translate(tx, ty float64)
• type Image
  • func NewImage(width, height int, filter Filter) (*Image, error)
  • func NewImageFromImage(source image.Image, filter Filter) (*Image, error)
  • func (i *Image) At(x, y int) color.Color
  • func (i *Image) Bounds() image.Rectangle
  • func (i *Image) Clear() error
  • func (i *Image) ColorModel() color.Model
  • func (i *Image) Dispose() error
  • func (i *Image) DrawImage(img *Image, options *DrawImageOptions) error
  • func (i *Image) DrawRectShader(width, height int, shader *Shader, options *DrawRectShaderOptions)
  • func (i *Image) DrawTriangles(vertices []Vertex, indices []uint16, img *Image, options *DrawTrianglesOptions)
  • func (i *Image) DrawTrianglesShader(vertices []Vertex, indices []uint16, shader *Shader, ...)
  • func (i *Image) Fill(clr color.Color) error
  • func (i *Image) ReplacePixels(pixels []byte) error
  • func (i *Image) Set(x, y int, clr color.Color)
  • func (i *Image) Size() (width, height int)
  • func (i *Image) SubImage(r image.Rectangle) image.Image
• type ImagePart
• type ImageParts
• type Key
  • func (k Key) String() string
• type MouseButton
• type Shader
  • func NewShader(src []byte) (*Shader, error)
  • func (s *Shader) Dispose()
• type Touch
  • func Touches() []Touch
• type Vertex

Constants

const ColorMDim = affine.ColorMDim

ColorMDim is a dimension of a ColorM.

const DefaultTPS = 60

DefaultTPS represents a default ticks per second, that represents how many times game updating happens in a second.

const FPS = DefaultTPS

FPS represents the default TPS (tick per second). This is for backward compatibility.

Deprecated: (as of 1.8.0) Use DefaultTPS instead.

const GeoMDim = 3

GeoMDim is a dimension of a GeoM.

const MaxIndicesNum = graphics.IndicesNum

MaxIndicesNum is the maximum number of indices for DrawTriangles.

const UncappedTPS = clock.UncappedTPS

UncappedTPS is a special TPS value that means the game doesn't have limitation on TPS.

Variables

var MaxImageSize = 4096

MaxImageSize represented the maximum size of an image, but now this constant is deprecated.

Deprecated: (as of 1.7.0) No replacement so far.

TODO: Make this replacement (#541)

Functions

func CurrentFPS

func CurrentFPS() float64

CurrentFPS returns the current number of FPS (frames per second), that represents how many swapping buffer happens per second.

On some environments, CurrentFPS doesn't return a reliable value since vsync doesn't work well there. If you want to measure the application's speed, Use CurrentTPS.

CurrentFPS is concurrent-safe.

func CurrentTPS

func CurrentTPS() float64

CurrentTPS returns the current TPS (ticks per second), that represents how many update function is called in a second.

CurrentTPS is concurrent-safe.

func CursorPosition

func CursorPosition() (x, y int)

CursorPosition returns a position of a mouse cursor relative to the game screen (window). The cursor position is 'logical' position and this considers the scale of the screen.

CursorPosition is concurrent-safe.

func DeviceScaleFactor

func DeviceScaleFactor() float64

DeviceScaleFactor returns a device scale factor value of the current monitor which the window belongs to.

DeviceScaleFactor returns a meaningful value on high-DPI display environment, otherwise DeviceScaleFactor returns 1.

DeviceScaleFactor might panic on init function on some devices like Android. Then, it is not recommended to call DeviceScaleFactor from init functions.

DeviceScaleFactor must be called on the main thread before the main loop, and is concurrent-safe after the main loop.

func GamepadAxis

func GamepadAxis(id int, axis int) float64

GamepadAxis returns the float value [-1.0 - 1.0] of the given gamepad (id)'s axis (axis).

GamepadAxis is concurrent-safe.

GamepadAxis always returns 0 on iOS.

func GamepadAxisNum

func GamepadAxisNum(id int) int

GamepadAxisNum returns the number of axes of the gamepad (id).

GamepadAxisNum is concurrent-safe.

GamepadAxisNum always returns 0 on iOS.

func GamepadButtonNum

func GamepadButtonNum(id int) int

GamepadButtonNum returns the number of the buttons of the given gamepad (id).

GamepadButtonNum is concurrent-safe.

GamepadButtonNum always returns 0 on iOS.

func GamepadIDs

func GamepadIDs() []int

GamepadIDs returns a slice indicating available gamepad IDs.

GamepadIDs is concurrent-safe.

GamepadIDs always returns an empty slice on iOS.

func GamepadName

func GamepadName(id int) string

GamepadName returns a string with the name. This function may vary in how it returns descriptions for the same device across platforms for example the following drivers/platforms see a Xbox One controller as the following:

• Windows: "Xbox Controller"
• Chrome: "Xbox 360 Controller (XInput STANDARD GAMEPAD)"
• Firefox: "xinput"

GamepadName always returns an empty string on iOS.

GamepadName is concurrent-safe.

func GamepadSDLID

func GamepadSDLID(id int) string

GamepadSDLID returns a string with the GUID generated in the same way as SDL. To detect devices, see also the community project of gamepad devices database: https://github.com/gabomdq/SDL_GameControllerDB

GamepadSDLID always returns an empty string on browsers and mobiles.

GamepadSDLID is concurrent-safe.

func InputChars

func InputChars() []rune

InputChars return "printable" runes read from the keyboard at the time update is called.

InputChars represents the environment's locale-dependent translation of keyboard input to Unicode characters.

IsKeyPressed is based on a mapping of device (US keyboard) codes to input device keys. "Control" and modifier keys should be handled with IsKeyPressed.

InputChars is concurrent-safe.

On Android (ebitenmobile), EbitenView must be focusable to enable to handle keyboard keys.

Keyboards don't work on iOS yet (#1090).

func IsCursorVisible

func IsCursorVisible() bool

IsCursorVisible reports whether the cursor is visible or not.

Deprecated: (as of 1.11.0-alpha) Use CursorMode instead.

func IsDrawingSkipped

func IsDrawingSkipped() bool

IsDrawingSkipped returns true if rendering result is not adopted. It is recommended to skip drawing images or screen when IsDrawingSkipped is true.

The typical code with IsDrawingSkipped is this:

func update(screen *ebiten.Image) error {

    // Update the state.

    // When IsDrawingSkipped is true, the rendered result is not adopted.
    // Skip rendering then.
    if ebiten.IsDrawingSkipped() {
        return nil
    }

    // Draw something to the screen.

    return nil
}

IsDrawingSkipped is useful if you use Run function or RunGame function without implementing Game's Draw. Otherwise, i.e., if you use RunGame function with implementing Game's Draw, IsDrawingSkipped should not be used. If you use RunGame and Draw, IsDrawingSkipped always returns true.

IsDrawingSkipped is concurrent-safe.

func IsFocused

func IsFocused() bool

IsFocused returns a boolean value indicating whether the game is in focus or in the foreground.

IsFocused will only return true if IsRunnableOnUnfocused is false.

IsFocused is concurrent-safe.

func IsFullscreen

func IsFullscreen() bool

IsFullscreen reports whether the current mode is fullscreen or not.

IsFullscreen always returns false on browsers. IsFullscreen works as this as of 1.10.0-alpha. Before that, IsFullscreen reported whether the current mode is fullscreen or not.

IsFullscreen always returns false on mobiles.

IsFullscreen is concurrent-safe.

func IsGamepadButtonPressed

func IsGamepadButtonPressed(id int, button GamepadButton) bool

IsGamepadButtonPressed returns the boolean indicating the given button of the gamepad (id) is pressed or not.

If you want to know whether the given button of gamepad (id) started being pressed in the current frame, use inpututil.IsGamepadButtonJustPressed

IsGamepadButtonPressed is concurrent-safe.

The relationships between physical buttons and buttion IDs depend on environments. There can be differences even between Chrome and Firefox.

IsGamepadButtonPressed always returns false on iOS.

func IsKeyPressed

func IsKeyPressed(key Key) bool

IsKeyPressed returns a boolean indicating whether key is pressed.

If you want to know whether the key started being pressed in the current frame, use inpututil.IsKeyJustPressed

Known issue: On Edge browser, some keys don't work well:

• KeyKPEnter and KeyKPEqual are recognized as KeyEnter and KeyEqual.
• KeyPrintScreen is only treated at keyup event.

IsKeyPressed is concurrent-safe.

On Android (ebitenmobile), EbitenView must be focusable to enable to handle keyboard keys.

Keyboards don't work on iOS yet (#1090).

func IsMouseButtonPressed

func IsMouseButtonPressed(mouseButton MouseButton) bool

IsMouseButtonPressed returns a boolean indicating whether mouseButton is pressed.

If you want to know whether the mouseButton started being pressed in the current frame, use inpututil.IsMouseButtonJustPressed

IsMouseButtonPressed is concurrent-safe.

Note that touch events not longer affect IsMouseButtonPressed's result as of 1.4.0-alpha. Use Touches instead.

func IsRunnableInBackground

func IsRunnableInBackground() bool

IsRunnableInBackground is an old name for IsRunnableOnUnfocused.

Deprecated: (as of 1.11.0) Use IsRunnableOnUnfocused instead.

func IsRunnableOnUnfocused

func IsRunnableOnUnfocused() bool

IsRunnableOnUnfocused returns a boolean value indicating whether the game runs even in background.

IsRunnableOnUnfocused is concurrent-safe.

func IsRunningSlowly

func IsRunningSlowly() bool

IsRunningSlowly is an old name for IsDrawingSkipped.

Deprecated: (as of 1.8.0) Use Game's Draw function instead.

func IsScreenClearedEveryFrame

func IsScreenClearedEveryFrame() bool

IsScreenClearedEveryFrame returns true if the frame isn't cleared at the beginning.

IsScreenClearedEveryFrame is concurrent-safe.

func IsScreenTransparent

func IsScreenTransparent() bool

IsScreenTransparent reports whether the window is transparent.

IsScreenTransparent is concurrent-safe.

func IsVsyncEnabled

func IsVsyncEnabled() bool

IsVsyncEnabled returns a boolean value indicating whether the game uses the display's vsync.

IsVsyncEnabled is concurrent-safe.

func IsWindowDecorated

func IsWindowDecorated() bool

IsWindowDecorated reports whether the window is decorated.

IsWindowDecorated is concurrent-safe.

func IsWindowFloating

func IsWindowFloating() bool

IsWindowFloating reports whether the window is always shown above all the other windows.

IsWindowFloating returns false on browsers and mobiles.

IsWindowFloating is concurrent-safe.

func IsWindowMaximized

func IsWindowMaximized() bool

IsWindowMaximized reports whether the window is maximized or not.

IsWindowMaximized returns false when the window is not resizable.

IsWindowMaximized always returns false on browsers and mobiles.

IsWindowMaximized is concurrent-safe.

func IsWindowMinimized

func IsWindowMinimized() bool

IsWindowMinimized reports whether the window is minimized or not.

IsWindowMinimized always returns false on browsers and mobiles.

IsWindowMinimized is concurrent-safe.

func IsWindowResizable

func IsWindowResizable() bool

IsWindowResizable reports whether the window is resizable by the user's dragging on desktops. On the other environments, IsWindowResizable always returns false.

IsWindowResizable is concurrent-safe.

func MaxTPS

func MaxTPS() int

MaxTPS returns the current maximum TPS.

MaxTPS is concurrent-safe.

func MaximizeWindow

func MaximizeWindow()

MaximizeWindow maximizes the window.

MaximizeWindow panics when the window is not resizable.

MaximizeWindow does nothing on browsers or mobiles.

MaximizeWindow is concurrent-safe.

func MinimizeWindow

func MinimizeWindow()

MinimizeWindow minimizes the window.

If the main loop does not start yet, MinimizeWindow does nothing.

MinimizeWindow does nothing on browsers or mobiles.

MinimizeWindow is concurrent-safe.

func MonitorSize

func MonitorSize() (int, int)

MonitorSize is an old name for ScreenSizeInFullscreen.

Deprecated: (as of 1.8.0) Use ScreenSizeInFullscreen instead.

func RestoreWindow

func RestoreWindow()

RestoreWindow restores the window from its maximized or minimized state.

RestoreWindow panics when the window is not maximized nor minimized.

RestoreWindow is concurrent-safe.

func Run

func Run(f func(*Image) error, width, height int, scale float64, title string) error

Run starts the main loop and runs the game.

Deprecated: (as of 1.12.0) Use RunGame instead.

f is a function which is called at every frame. The argument (*Image) is the render target that represents the screen. The screen size is based on the given values (width and height).

Run is a shorthand for RunGame, but there are some restrictions. If you want to resize the window by dragging, use RunGame instead.

A window size is based on the given values (width, height and scale).

scale is used to enlarge the screen on desktops. scale is ignored on browsers or mobiles. Note that the actual screen is multiplied not only by the given scale but also by the device scale on high-DPI display. If you pass inverse of the device scale, you can disable this automatical device scaling as a result. You can get the device scale by DeviceScaleFactor function.

On browsers, the scale is automatically adjusted. It is strongly recommended to use iframe if you embed an Ebiten application in your website. scale works as this as of 1.10.0-alpha. Before that, scale affected the rendering scale.

On mobiles, if you use ebitenmobile command, the scale is automatically adjusted.

Run must be called on the main thread. Note that Ebiten bounds the main goroutine to the main OS thread by runtime.LockOSThread.

Ebiten tries to call f 60 times a second by default. In other words, TPS (ticks per second) is 60 by default. This is not related to framerate (display's refresh rate).

f is not called when the window is in background by default. This setting is configurable with SetRunnableOnUnfocused.

The given scale is ignored on fullscreen mode or gomobile-build mode.

On non-GopherJS environments, Run returns error when 1) OpenGL error happens, 2) audio error happens or 3) f returns error. In the case of 3), Run returns the same error.

On GopherJS, Run returns immediately. It is because the 'main' goroutine cannot be blocked on GopherJS due to the bug (gopherjs/gopherjs#826). When an error happens, this is shown as an error on the console.

The size unit is device-independent pixel.

Don't call Run twice or more in one process.

func RunGame

func RunGame(game Game) error

RunGame starts the main loop and runs the game. game's Update function is called every tick to update the game logic. game's Draw function is, if it exists, called every frame to draw the screen. game's Layout function is called when necessary, and you can specify the logical screen size by the function.

game must implement Game interface. Game's Draw function is optional, but it is recommended to implement Draw to seperate updating the logic and rendering.

RunGame is a more flexibile form of Run due to game's Layout function. You can make a resizable window if you use RunGame, while you cannot if you use Run. RunGame is more sophisticated way than Run and hides the notion of 'scale'.

While Run specifies the window size, RunGame does not. You need to call SetWindowSize before RunGame if you want. Otherwise, a default window size is adopted.

Some functions (ScreenScale, SetScreenScale, SetScreenSize) are not available with RunGame.

On browsers, it is strongly recommended to use iframe if you embed an Ebiten application in your website.

RunGame must be called on the main thread. Note that Ebiten bounds the main goroutine to the main OS thread by runtime.LockOSThread.

Ebiten tries to call game's Update function 60 times a second by default. In other words, TPS (ticks per second) is 60 by default. This is not related to framerate (display's refresh rate).

game's Update is not called when the window is in background by default. This setting is configurable with SetRunnableOnUnfocused.

On non-GopherJS environments, RunGame returns error when 1) OpenGL error happens, 2) audio error happens or 3) f returns error. In the case of 3), RunGame returns the same error.

On GopherJS, RunGame returns immediately. It is because the 'main' goroutine cannot be blocked on GopherJS due to the bug (gopherjs/gopherjs#826). When an error happens, this is shown as an error on the console.

The size unit is device-independent pixel.

Don't call RunGame twice or more in one process.

func RunGameWithoutMainLoop

func RunGameWithoutMainLoop(game Game)

RunGameWithoutMainLoop runs the game, but don't call the loop on the main (UI) thread. Different from Run, RunGameWithoutMainLoop returns immediately.

Ebiten users should NOT call RunGameWithoutMainLoop. Instead, functions in github.com/hajimehoshi/ebiten/mobile package calls this.

func ScreenScale

func ScreenScale() float64

ScreenScale returns the game screen scale.

Deprecated: (as of 1.11.0-alpha) Use WindowSize instead.

func ScreenSizeInFullscreen

func ScreenSizeInFullscreen() (int, int)

ScreenSizeInFullscreen returns the size in device-independent pixels when the game is fullscreen. The adopted monitor is the 'current' monitor which the window belongs to. The returned value can be given to Run or SetSize function if the perfectly fit fullscreen is needed.

On browsers, ScreenSizeInFullscreen returns the 'window' (global object) size, not 'screen' size since an Ebiten game should not know the outside of the window object. For more details, see SetFullscreen API comment.

On mobiles, ScreenSizeInFullscreen returns (0, 0) so far.

ScreenSizeInFullscreen's use cases are limited. If you are making a fullscreen application, you can use RunGame and the Game interface's Layout function instead. If you are making a not-fullscreen application but the application's behavior depends on the monitor size, ScreenSizeInFullscreen is useful.

ScreenSizeInFullscreen must be called on the main thread before ebiten.Run, and is concurrent-safe after ebiten.Run.

func SetCursorMode

func SetCursorMode(mode CursorModeType)

SetCursorMode sets the render and capture mode of the mouse cursor. CursorModeVisible sets the cursor to always be visible. CursorModeHidden hides the system cursor when over the window. CursorModeCaptured hides the system cursor and locks it to the window.

On browsers, only CursorModeVisible and CursorModeHidden are supported.

SetCursorMode does nothing on mobiles.

SetCursorMode is concurrent-safe.

func SetCursorVisibility

func SetCursorVisibility(visible bool)

SetCursorVisibility sets the cursor visibility.

Deprecated: (as of 1.6.0-alpha) Use SetCursorMode instead.

func SetCursorVisible

func SetCursorVisible(visible bool)

SetCursorVisible sets the cursor visibility.

Deprecated: (as of 1.11.0-alpha) Use SetCursorMode instead.

func SetFullscreen

func SetFullscreen(fullscreen bool)

SetFullscreen changes the current mode to fullscreen or not on desktops.

On fullscreen mode, the game screen is automatically enlarged to fit with the monitor. The current scale value is ignored.

On desktops, Ebiten uses 'windowed' fullscreen mode, which doesn't change your monitor's resolution.

SetFullscreen does nothing on browsers. SetFullscreen works as this as of 1.10.0-alpha. Before that, SetFullscreen affected the fullscreen mode.

SetFullscreen does nothing on mobiles.

SetFullscreen is concurrent-safe.

func SetInitFocused

func SetInitFocused(focused bool)

SetInitFocused sets whether the application is focused on show. The default value is true, i.e., the application is focused. Note that the application does not proceed if this is not focused by default. This behavior can be changed by SetRunnableInBackground.

SetInitFocused does nothing on mobile.

SetInitFocused panics if this is called after the main loop.

SetInitFocused is cuncurrent-safe.

func SetMaxTPS

func SetMaxTPS(tps int)

SetMaxTPS sets the maximum TPS (ticks per second), that represents how many updating function is called per second. The initial value is 60.

If tps is UncappedTPS, TPS is uncapped and the game is updated per frame. If tps is negative but not UncappedTPS, SetMaxTPS panics.

SetMaxTPS is concurrent-safe.

func SetRunnableInBackground

func SetRunnableInBackground(runnableInBackground bool)

SetRunnableInBackground is an old name for SetRunnableOnUnfocused.

Deprecated: (as of 1.11.0-alpha) Use SetRunnableOnUnfocused instead.

func SetRunnableOnUnfocused

func SetRunnableOnUnfocused(runnableOnUnfocused bool)

SetRunnableOnUnfocused sets the state if the game runs even in background.

If the given value is true, the game runs in background e.g. when losing focus. The initial state is false.

Known issue: On browsers, even if the state is on, the game doesn't run in background tabs. This is because browsers throttles background tabs not to often update.

SetRunnableOnUnfocused does nothing on mobiles so far.

SetRunnableOnUnfocused is concurrent-safe.

func SetScreenClearedEveryFrame

func SetScreenClearedEveryFrame(cleared bool)

SetScreenClearedEveryFrame enables or disables the clearing of the screen at the beginning of each frame. The default value is false and the screen is cleared each frame by default.

SetScreenClearedEveryFrame is concurrent-safe.

func SetScreenScale

func SetScreenScale(scale float64)

SetScreenScale sets the game screen scale and resizes the window.

Deprecated: (as of 1.11.0-alpha). Use SetWindowSize instead.

func SetScreenSize

func SetScreenSize(width, height int)

SetScreenSize sets the game screen size and resizes the window.

Deprecated: (as of 1.11.0) Use SetWindowSize and RunGame (Game's Layout) instead.

func SetScreenTransparent

func SetScreenTransparent(transparent bool)

SetScreenTransparent sets the state if the window is transparent.

SetScreenTransparent panics if SetScreenTransparent is called after the main loop.

SetScreenTransparent does nothing on mobiles.

SetScreenTransparent is concurrent-safe.

func SetVsyncEnabled

func SetVsyncEnabled(enabled bool)

SetVsyncEnabled sets a boolean value indicating whether the game uses the display's vsync.

If the given value is true, the game tries to sync the display's refresh rate. If false, the game ignores the display's refresh rate. The initial value is true. By disabling vsync, the game works more efficiently but consumes more CPU.

Note that the state doesn't affect TPS (ticks per second, i.e. how many the run function is updated per second).

SetVsyncEnabled does nothing on mobiles so far.

SetVsyncEnabled is concurrent-safe.

func SetWindowDecorated

func SetWindowDecorated(decorated bool)

SetWindowDecorated sets the state if the window is decorated.

The window is decorated by default.

SetWindowDecorated works only on desktops. SetWindowDecorated does nothing on other platforms.

SetWindowDecorated is concurrent-safe.

func SetWindowFloating

func SetWindowFloating(float bool)

SetWindowFloating sets the state whether the window is always shown above all the other windows.

SetWindowFloating does nothing on browsers or mobiles.

SetWindowFloating is concurrent-safe.

func SetWindowIcon

func SetWindowIcon(iconImages []image.Image)

SetWindowIcon sets the icon of the game window.

If len(iconImages) is 0, SetWindowIcon reverts the icon to the default one.

For desktops, see the document of glfwSetWindowIcon of GLFW 3.2:

This function sets the icon of the specified window.
If passed an array of candidate images, those of or closest to the sizes
desired by the system are selected.
If no images are specified, the window reverts to its default icon.

The desired image sizes varies depending on platform and system settings.
The selected images will be rescaled as needed.
Good sizes include 16x16, 32x32 and 48x48.

As macOS windows don't have icons, SetWindowIcon doesn't work on macOS.

SetWindowIcon doesn't work on browsers or mobiles.

SetWindowIcon is concurrent-safe.

func SetWindowPosition

func SetWindowPosition(x, y int)

SetWindowPosition sets the window position. The origin position is the left-upper corner of the current monitor. The unit is device-independent pixels.

SetWindowPosition does nothing on fullscreen mode.

SetWindowPosition does nothing on browsers and mobiles.

SetWindowPosition is concurrent-safe.

func SetWindowResizable

func SetWindowResizable(resizable bool)

SetWindowResizable sets whether the window is resizable by the user's dragging on desktops. On the other environments, SetWindowResizable does nothing.

The window is not resizable by default.

If SetWindowResizable is called with true and Run is used, SetWindowResizable panics. Use RunGame instead.

SetWindowResizable is concurrent-safe.

func SetWindowSize

func SetWindowSize(width, height int)

SetWindowSize sets the window size on desktops. SetWindowSize does nothing on other environments.

On fullscreen mode, SetWindowSize sets the original window size.

SetWindowSize panics if width or height is not a positive number.

SetWindowSize is concurrent-safe.

func SetWindowTitle

func SetWindowTitle(title string)

SetWindowTitle sets the title of the window.

SetWindowTitle updated the title on browsers, but now does nothing on browsers as of 1.11.0-alpha.

SetWindowTitle does nothing on mobiles.

SetWindowTitle is concurrent-safe.

func TouchIDs

func TouchIDs() []int

TouchIDs returns the current touch states.

If you want to know whether a touch started being pressed in the current frame, use inpututil.JustPressedTouchIDs

TouchIDs returns nil when there are no touches. TouchIDs always returns nil on desktops.

TouchIDs is concurrent-safe.

func TouchPosition

func TouchPosition(id int) (int, int)

TouchPosition returns the position for the touch of the specified ID.

If the touch of the specified ID is not present, TouchPosition returns (0, 0).

TouchPosition is cuncurrent-safe.

func Wheel

func Wheel() (xoff, yoff float64)

Wheel returns the x and y offset of the mouse wheel or touchpad scroll. It returns 0 if the wheel isn't being rolled.

Wheel is concurrent-safe.

func WindowPosition

func WindowPosition() (x, y int)

WindowPosition returns the window position. The origin position is the left-upper corner of the current monitor. The unit is device-independent pixels.

WindowPosition panics if the main loop does not start yet.

WindowPosition returns the last window position on fullscreen mode.

WindowPosition returns (0, 0) on browsers and mobiles.

WindowPosition is concurrent-safe.

func WindowSize

func WindowSize() (int, int)

WindowSize returns the window size on desktops. WindowSize returns (0, 0) on other environments.

On fullscreen mode, WindowSize returns the original window size.

WindowSize is concurrent-safe.

Types

type Address

type Address int

Address represents a sampler address mode.

const (
	// AddressClampToZero means that out-of-range texture coordinates return 0 (transparent).
	AddressClampToZero Address = Address(driver.AddressClampToZero)

	// AddressRepeat means that texture coordinates wrap to the other side of the texture.
	AddressRepeat Address = Address(driver.AddressRepeat)

	// AddressUnsafe means there is no guarantee when the texture coodinates are out of range.
	AddressUnsafe Address = Address(driver.AddressUnsafe)
)

type ColorM

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

A ColorM represents a matrix to transform coloring when rendering an image.

A ColorM is applied to the straight alpha color while an Image's pixels' format is alpha premultiplied. Before applying a matrix, a color is un-multiplied, and after applying the matrix, the color is multiplied again.

The initial value is identity.

func Monochrome

func Monochrome() ColorM

Monochrome returns a color matrix for monochrome.

Deprecated: (as of 1.6.0) Use ChangeHSV(0, 0, 1) instead.

func RotateHue

func RotateHue(theta float64) ColorM

RotateHue returns a color matrix for chanting the hue.

Deprecated: (as of 1.2.0-alpha) Use RotateHue member function instead.

func ScaleColor

func ScaleColor(r, g, b, a float64) ColorM

ScaleColor returns a color matrix for scaling.

Deprecated: (as of 1.2.0) Use Scale instead.

func TranslateColor

func TranslateColor(r, g, b, a float64) ColorM

TranslateColor returns a color matrix for translating.

Deprecated: (as of 1.2.0) Use Translate instead.

func (*ColorM) Add

func (c *ColorM) Add(other ColorM)

Add adds a matrix, but in a wrong way.

Deprecated: (as of 1.5.0) Do not use this.

Note that this doesn't make sense as an operation for affine matrices.

func (*ColorM) Apply

func (c *ColorM) Apply(clr color.Color) color.Color

Apply pre-multiplies a vector (r, g, b, a, 1) by the matrix where r, g, b, and a are clr's values in straight-alpha format. In other words, Apply calculates ColorM * (r, g, b, a, 1)^T.

func (*ColorM) ChangeHSV

func (c *ColorM) ChangeHSV(hueTheta float64, saturationScale float64, valueScale float64)

ChangeHSV changes HSV (Hue-Saturation-Value) values. hueTheta is a radian value to rotate hue. saturationScale is a value to scale saturation. valueScale is a value to scale value (a.k.a. brightness).

This conversion uses RGB to/from YCrCb conversion.

func (*ColorM) Concat

func (c *ColorM) Concat(other ColorM)

Concat multiplies a color matrix with the other color matrix. This is same as muptiplying the matrix other and the matrix c in this order.

func (*ColorM) Element

func (c *ColorM) Element(i, j int) float64

Element returns a value of a matrix at (i, j).

func (*ColorM) Invert

func (c *ColorM) Invert()

Invert inverts the matrix. If c is not invertible, Invert panics.

func (*ColorM) IsInvertible

func (c *ColorM) IsInvertible() bool

IsInvertible returns a boolean value indicating whether the matrix c is invertible or not.

func (*ColorM) Reset

func (c *ColorM) Reset()

Reset resets the ColorM as identity.

func (*ColorM) RotateHue

func (c *ColorM) RotateHue(theta float64)

RotateHue rotates the hue. theta represents rotating angle in radian.

func (*ColorM) Scale

func (c *ColorM) Scale(r, g, b, a float64)

Scale scales the matrix by (r, g, b, a).

func (*ColorM) SetElement

func (c *ColorM) SetElement(i, j int, element float64)

SetElement sets an element at (i, j).

func (*ColorM) String

func (c *ColorM) String() string

String returns a string representation of ColorM.

func (*ColorM) Translate

func (c *ColorM) Translate(r, g, b, a float64)

Translate translates the matrix by (r, g, b, a).

type CompositeMode

type CompositeMode int

CompositeMode represents Porter-Duff composition mode.

const (
	// Regular alpha blending
	// c_out = c_src + c_dst × (1 - α_src)
	CompositeModeSourceOver CompositeMode = CompositeMode(driver.CompositeModeSourceOver)

	// c_out = 0
	CompositeModeClear CompositeMode = CompositeMode(driver.CompositeModeClear)

	// c_out = c_src
	CompositeModeCopy CompositeMode = CompositeMode(driver.CompositeModeCopy)

	// c_out = c_dst
	CompositeModeDestination CompositeMode = CompositeMode(driver.CompositeModeDestination)

	// c_out = c_src × (1 - α_dst) + c_dst
	CompositeModeDestinationOver CompositeMode = CompositeMode(driver.CompositeModeDestinationOver)

	// c_out = c_src × α_dst
	CompositeModeSourceIn CompositeMode = CompositeMode(driver.CompositeModeSourceIn)

	// c_out = c_dst × α_src
	CompositeModeDestinationIn CompositeMode = CompositeMode(driver.CompositeModeDestinationIn)

	// c_out = c_src × (1 - α_dst)
	CompositeModeSourceOut CompositeMode = CompositeMode(driver.CompositeModeSourceOut)

	// c_out = c_dst × (1 - α_src)
	CompositeModeDestinationOut CompositeMode = CompositeMode(driver.CompositeModeDestinationOut)

	// c_out = c_src × α_dst + c_dst × (1 - α_src)
	CompositeModeSourceAtop CompositeMode = CompositeMode(driver.CompositeModeSourceAtop)

	// c_out = c_src × (1 - α_dst) + c_dst × α_src
	CompositeModeDestinationAtop CompositeMode = CompositeMode(driver.CompositeModeDestinationAtop)

	// c_out = c_src × (1 - α_dst) + c_dst × (1 - α_src)
	CompositeModeXor CompositeMode = CompositeMode(driver.CompositeModeXor)

	// Sum of source and destination (a.k.a. 'plus' or 'additive')
	// c_out = c_src + c_dst
	CompositeModeLighter CompositeMode = CompositeMode(driver.CompositeModeLighter)

	// The product of source and destination (a.k.a 'multiply blend mode')
	// c_out = c_src * c_dst
	CompositeModeMultiply CompositeMode = CompositeMode(driver.CompositeModeMultiply)
)

This name convention follows CSS compositing: https://drafts.fxtf.org/compositing-2/.

In the comments, c_src, c_dst and c_out represent alpha-premultiplied RGB values of source, destination and output respectively. α_src and α_dst represent alpha values of source and destination respectively.

type CursorModeType

type CursorModeType int

CursorModeType represents a render and coordinate mode of a mouse cursor.

const (
	CursorModeVisible  CursorModeType = CursorModeType(driver.CursorModeVisible)
	CursorModeHidden   CursorModeType = CursorModeType(driver.CursorModeHidden)
	CursorModeCaptured CursorModeType = CursorModeType(driver.CursorModeCaptured)
)

func CursorMode

func CursorMode() CursorModeType

CursorMode returns the current cursor mode.

On browsers, only CursorModeVisible and CursorModeHidden are supported.

CursorMode returns CursorModeHidden on mobiles.

CursorMode is concurrent-safe.

type DrawImageOptions

type DrawImageOptions struct {
	// GeoM is a geometry matrix to draw.
	// The default (zero) value is identity, which draws the image at (0, 0).
	GeoM GeoM

	// ColorM is a color matrix to draw.
	// The default (zero) value is identity, which doesn't change any color.
	ColorM ColorM

	// CompositeMode is a composite mode to draw.
	// The default (zero) value is regular alpha blending.
	CompositeMode CompositeMode

	// Filter is a type of texture filter.
	// The default (zero) value is FilterDefault.
	//
	// Filter can also be specified at NewImage* functions, but
	// specifying filter at DrawImageOptions is recommended (as of 1.7.0).
	//
	// If both Filter specified at NewImage* and DrawImageOptions are FilterDefault,
	// FilterNearest is used.
	// If either is FilterDefault and the other is not, the latter is used.
	// Otherwise, Filter specified at DrawImageOptions is used.
	Filter Filter

	// Deprecated: (as of 1.5.0) Use SubImage instead.
	ImageParts ImageParts

	// Deprecated: (as of 1.1.0) Use SubImage instead.
	Parts []ImagePart

	// Deprecated: (as of 1.9.0) Use SubImage instead.
	SourceRect *image.Rectangle
}

DrawImageOptions represents options for DrawImage.

type DrawRectShaderOptions

type DrawRectShaderOptions struct {
	// GeoM is a geometry matrix to draw.
	// The default (zero) value is identity, which draws the rectangle at (0, 0).
	GeoM GeoM

	// CompositeMode is a composite mode to draw.
	// The default (zero) value is regular alpha blending.
	CompositeMode CompositeMode

	// Uniforms is a set of uniform variables for the shader.
	// The keys are the names of the uniform variables.
	// The values must be float or []float.
	// If the uniform variable type is an array, a vector or a matrix,
	// you have to specify linearly flattened values as a slice.
	// For example, if the uniform variable type is [4]vec4, the number of the slice values will be 16.
	Uniforms map[string]interface{}

	// Images is a set of the source images.
	// All the image must be the same size with the rectangle.
	Images [4]*Image
}

DrawRectShaderOptions represents options for DrawRectShader.

This API is experimental.

type DrawTrianglesOptions

type DrawTrianglesOptions struct {
	// ColorM is a color matrix to draw.
	// The default (zero) value is identity, which doesn't change any color.
	// ColorM is applied before vertex color scale is applied.
	//
	// If Shader is not nil, ColorM is ignored.
	ColorM ColorM

	// CompositeMode is a composite mode to draw.
	// The default (zero) value is regular alpha blending.
	CompositeMode CompositeMode

	// Filter is a type of texture filter.
	// The default (zero) value is FilterDefault.
	Filter Filter

	// Address is a sampler address mode.
	// The default (zero) value is AddressClampToZero.
	Address Address
}

DrawTrianglesOptions represents options for DrawTriangles.

type DrawTrianglesShaderOptions

type DrawTrianglesShaderOptions struct {
	// CompositeMode is a composite mode to draw.
	// The default (zero) value is regular alpha blending.
	CompositeMode CompositeMode

	// Uniforms is a set of uniform variables for the shader.
	// The keys are the names of the uniform variables.
	// The values must be float or []float.
	// If the uniform variable type is an array, a vector or a matrix,
	// you have to specify linearly flattened values as a slice.
	// For example, if the uniform variable type is [4]vec4, the number of the slice values will be 16.
	Uniforms map[string]interface{}

	// Images is a set of the source images.
	// All the image must be the same size.
	Images [4]*Image
}

DrawTrianglesShaderOptions represents options for DrawTrianglesShader.

This API is experimental.

type Filter

type Filter int

Filter represents the type of texture filter to be used when an image is maginified or minified.

const (
	// FilterDefault represents the default filter.
	FilterDefault Filter = 0

	// FilterNearest represents nearest (crisp-edged) filter
	FilterNearest Filter = Filter(driver.FilterNearest)

	// FilterLinear represents linear filter
	FilterLinear Filter = Filter(driver.FilterLinear)
)

type Game

type Game interface {
	// Update updates a game by one tick. The given argument represents a screen image.
	//
	// Basically Update updates the game logic. Whether Update also draws the screen or not depends on the
	// existence of Draw implementation.
	//
	// The Draw function's definition is:
	//
	//     Draw(screen *Image)
	//
	// With Draw (the recommended way), Update updates only the game logic and Draw draws the screen.
	// In this case, the argument screen's updated content by Update is not adopted for the actual game screen,
	// and the screen's updated content by Draw is adopted instead.
	// In the first frame, it is ensured that Update is called at least once before Draw. You can use Update
	// to initialize the game state. After the first frame, Update might not be called or might be called once
	// or more for one frame. The frequency is determined by the current TPS (tick-per-second).
	//
	// Without Draw (the legacy way), Update updates the game logic and also draws the screen.
	// In this case, the argument screen's updated content by Update is adopted for the actual game screen.
	Update(screen *Image) error

	// Layout accepts a native outside size in device-independent pixels and returns the game's logical screen
	// size.
	//
	// On desktops, the outside is a window or a monitor (fullscreen mode). On browsers, the outside is a body
	// element. On mobiles, the outside is the view's size.
	//
	// Even though the outside size and the screen size differ, the rendering scale is automatically adjusted to
	// fit with the outside.
	//
	// Layout is called almost every frame.
	//
	// If Layout returns non-positive numbers, the caller can panic.
	//
	// You can return a fixed screen size if you don't care, or you can also return a calculated screen size
	// adjusted with the given outside size.
	Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int)
}

Game defines necessary functions for a game.

type GamepadButton

type GamepadButton int

A GamepadButton represents a gamepad button.

const (
	GamepadButton0   GamepadButton = GamepadButton(driver.GamepadButton0)
	GamepadButton1   GamepadButton = GamepadButton(driver.GamepadButton1)
	GamepadButton2   GamepadButton = GamepadButton(driver.GamepadButton2)
	GamepadButton3   GamepadButton = GamepadButton(driver.GamepadButton3)
	GamepadButton4   GamepadButton = GamepadButton(driver.GamepadButton4)
	GamepadButton5   GamepadButton = GamepadButton(driver.GamepadButton5)
	GamepadButton6   GamepadButton = GamepadButton(driver.GamepadButton6)
	GamepadButton7   GamepadButton = GamepadButton(driver.GamepadButton7)
	GamepadButton8   GamepadButton = GamepadButton(driver.GamepadButton8)
	GamepadButton9   GamepadButton = GamepadButton(driver.GamepadButton9)
	GamepadButton10  GamepadButton = GamepadButton(driver.GamepadButton10)
	GamepadButton11  GamepadButton = GamepadButton(driver.GamepadButton11)
	GamepadButton12  GamepadButton = GamepadButton(driver.GamepadButton12)
	GamepadButton13  GamepadButton = GamepadButton(driver.GamepadButton13)
	GamepadButton14  GamepadButton = GamepadButton(driver.GamepadButton14)
	GamepadButton15  GamepadButton = GamepadButton(driver.GamepadButton15)
	GamepadButton16  GamepadButton = GamepadButton(driver.GamepadButton16)
	GamepadButton17  GamepadButton = GamepadButton(driver.GamepadButton17)
	GamepadButton18  GamepadButton = GamepadButton(driver.GamepadButton18)
	GamepadButton19  GamepadButton = GamepadButton(driver.GamepadButton19)
	GamepadButton20  GamepadButton = GamepadButton(driver.GamepadButton20)
	GamepadButton21  GamepadButton = GamepadButton(driver.GamepadButton21)
	GamepadButton22  GamepadButton = GamepadButton(driver.GamepadButton22)
	GamepadButton23  GamepadButton = GamepadButton(driver.GamepadButton23)
	GamepadButton24  GamepadButton = GamepadButton(driver.GamepadButton24)
	GamepadButton25  GamepadButton = GamepadButton(driver.GamepadButton25)
	GamepadButton26  GamepadButton = GamepadButton(driver.GamepadButton26)
	GamepadButton27  GamepadButton = GamepadButton(driver.GamepadButton27)
	GamepadButton28  GamepadButton = GamepadButton(driver.GamepadButton28)
	GamepadButton29  GamepadButton = GamepadButton(driver.GamepadButton29)
	GamepadButton30  GamepadButton = GamepadButton(driver.GamepadButton30)
	GamepadButton31  GamepadButton = GamepadButton(driver.GamepadButton31)
	GamepadButtonMax GamepadButton = GamepadButton31
)

GamepadButtons

type GeoM

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

A GeoM represents a matrix to transform geometry when rendering an image.

The initial value is identity.

func RotateGeo

func RotateGeo(theta float64) GeoM

RotateGeo returns a geometry matrix for rotating.

Deprecated: (as of 1.2.0) Use Rotate instead.

func ScaleGeo

func ScaleGeo(x, y float64) GeoM

ScaleGeo returns a geometry matrix for scaling.

Deprecated: (as of 1.2.0) Use Scale instead.

func TranslateGeo

func TranslateGeo(tx, ty float64) GeoM

TranslateGeo returns a geometry matrix for translating.

Deprecated: (as of 1.2.0) Use Translate instead.

func (*GeoM) Add

func (g *GeoM) Add(other GeoM)

Add adds a matrix, but in a wrong way.

Deprecated: (as of 1.5.0) Do not use this.

Note that this doesn't make sense as an operation for affine matrices.

func (*GeoM) Apply

func (g *GeoM) Apply(x, y float64) (float64, float64)

Apply pre-multiplies a vector (x, y, 1) by the matrix. In other words, Apply calculates GeoM * (x, y, 1)^T. The return value is x and y values of the result vector.

func (*GeoM) Concat

func (g *GeoM) Concat(other GeoM)

Concat multiplies a geometry matrix with the other geometry matrix. This is same as muptiplying the matrix other and the matrix g in this order.

func (*GeoM) Element

func (g *GeoM) Element(i, j int) float64

Element returns a value of a matrix at (i, j).

func (*GeoM) Invert

func (g *GeoM) Invert()

Invert inverts the matrix. If g is not invertible, Invert panics.

func (*GeoM) IsInvertible

func (g *GeoM) IsInvertible() bool

IsInvertible returns a boolean value indicating whether the matrix g is invertible or not.

func (*GeoM) Reset

func (g *GeoM) Reset()

Reset resets the GeoM as identity.

func (*GeoM) Rotate

func (g *GeoM) Rotate(theta float64)

Rotate rotates the matrix by theta. The unit is radian.

func (*GeoM) Scale

func (g *GeoM) Scale(x, y float64)

Scale scales the matrix by (x, y).

func (*GeoM) SetElement

func (g *GeoM) SetElement(i, j int, element float64)

SetElement sets an element at (i, j).

func (*GeoM) Skew

func (g *GeoM) Skew(skewX, skewY float64)

Skew skews the matrix by (skewX, skewY). The unit is radian.

func (*GeoM) String

func (g *GeoM) String() string

String returns a string representation of GeoM.

func (*GeoM) Translate

func (g *GeoM) Translate(tx, ty float64)

Translate translates the matrix by (tx, ty).

type Image

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

Image represents a rectangle set of pixels. The pixel format is alpha-premultiplied RGBA. Image implements image.Image and draw.Image.

Functions of Image never returns error as of 1.5.0, and error values are always nil.

func NewImage

func NewImage(width, height int, filter Filter) (*Image, error)

NewImage returns an empty image.

If width or height is less than 1 or more than device-dependent maximum size, NewImage panics.

filter argument is just for backward compatibility. If you are not sure, specify FilterDefault.

Error returned by NewImage is always nil as of 1.5.0.

func NewImageFromImage

func NewImageFromImage(source image.Image, filter Filter) (*Image, error)

NewImageFromImage creates a new image with the given image (source).

If source's width or height is less than 1 or more than device-dependent maximum size, NewImageFromImage panics.

filter argument is just for backward compatibility. If you are not sure, specify FilterDefault.

Error returned by NewImageFromImage is always nil as of 1.5.0.

func (*Image) At

func (i *Image) At(x, y int) color.Color

At returns the color of the image at (x, y).

At loads pixels from GPU to system memory if necessary, which means that At can be slow.

At always returns a transparent color if the image is disposed.

Note that an important logic should not rely on values returned by At, since the returned values can include very slight differences between some machines.

At can't be called outside the main loop (ebiten.Run's updating function) starts (as of version 1.4.0).

func (*Image) Bounds

func (i *Image) Bounds() image.Rectangle

Bounds returns the bounds of the image.

func (*Image) Clear

func (i *Image) Clear() error

Clear resets the pixels of the image into 0.

When the image is disposed, Clear does nothing.

Clear always returns nil as of 1.5.0.

func (*Image) ColorModel

func (i *Image) ColorModel() color.Model

ColorModel returns the color model of the image.

func (*Image) Dispose

func (i *Image) Dispose() error

Dispose disposes the image data. After disposing, most of image functions do nothing and returns meaningless values.

Calling Dispose is not mandatory. GC automatically collects internal resources that no objects refer to. However, calling Dispose explicitly is helpful if memory usage matters.

When the image is disposed, Dipose does nothing.

Dipose always return nil as of 1.5.0.

func (*Image) DrawImage

func (i *Image) DrawImage(img *Image, options *DrawImageOptions) error

DrawImage draws the given image on the image i.

DrawImage accepts the options. For details, see the document of DrawImageOptions.

For drawing, the pixels of the argument image at the time of this call is adopted. Even if the argument image is mutated after this call, the drawing result is never affected.

When the image i is disposed, DrawImage does nothing. When the given image img is disposed, DrawImage panics.

When the given image is as same as i, DrawImage panics.

DrawImage works more efficiently as batches when the successive calls of DrawImages satisfy the below conditions:

• All render targets are same (A in A.DrawImage(B, op))
• Either all ColorM element values are same or all the ColorM have only diagonal ('scale') elements
• If only (*ColorM).Scale is applied to a ColorM, the ColorM has only diagonal elements. The other ColorM functions might modify the other elements.
• All CompositeMode values are same
• All Filter values are same

Even when all the above conditions are satisfied, multiple draw commands can be used in really rare cases. Ebiten images usually share an internal automatic texture atlas, but when you consume the atlas, or you create a huge image, those images cannot be on the same texture atlas. In this case, draw commands are separated. The texture atlas size is 4096x4096 so far. Another case is when you use an offscreen as a render source. An offscreen doesn't share the texture atlas with high probability.

For more performance tips, see https://ebiten.org/documents/performancetips.html

DrawImage always returns nil as of 1.5.0.

func (*Image) DrawRectShader

func (i *Image) DrawRectShader(width, height int, shader *Shader, options *DrawRectShaderOptions)

DrawRectShader draws a rectangle with the specified width and height with the specified shader.

For the details about the shader, see https://ebiten.org/documents/shader.html.

When one of the specified image is non-nil and is disposed, DrawRectShader panics.

When the image i is disposed, DrawRectShader does nothing.

This API is experimental.

func (*Image) DrawTriangles

func (i *Image) DrawTriangles(vertices []Vertex, indices []uint16, img *Image, options *DrawTrianglesOptions)

DrawTriangles draws triangles with the specified vertices and their indices.

If len(indices) is not multiple of 3, DrawTriangles panics.

If len(indices) is more than MaxIndicesNum, DrawTriangles panics.

The rule in which DrawTriangles works effectively is same as DrawImage's.

When the given image is disposed, DrawTriangles panics.

When the image i is disposed, DrawTriangles does nothing.

func (*Image) DrawTrianglesShader

func (i *Image) DrawTrianglesShader(vertices []Vertex, indices []uint16, shader *Shader, options *DrawTrianglesShaderOptions)

DrawTrianglesShader draws triangles with the specified vertices and their indices with the specified shader.

For the details about the shader, see https://ebiten.org/documents/shader.html.

If len(indices) is not multiple of 3, DrawTrianglesShader panics.

If len(indices) is more than MaxIndicesNum, DrawTrianglesShader panics.

When a specified image is non-nil and is disposed, DrawTrianglesShader panics.

When the image i is disposed, DrawTrianglesShader does nothing.

This API is experimental.

func (*Image) Fill

func (i *Image) Fill(clr color.Color) error

Fill fills the image with a solid color.

When the image is disposed, Fill does nothing.

Fill always returns nil as of 1.5.0.

func (*Image) ReplacePixels

func (i *Image) ReplacePixels(pixels []byte) error

ReplacePixels replaces the pixels of the image with p.

The given p must represent RGBA pre-multiplied alpha values. len(pix) must equal to 4 * (bounds width) * (bounds height).

ReplacePixels works on a sub-image.

When len(pix) is not appropriate, ReplacePixels panics.

When the image is disposed, ReplacePixels does nothing.

ReplacePixels always returns nil as of 1.5.0.

func (*Image) Set

func (i *Image) Set(x, y int, clr color.Color)

Set sets the color at (x, y).

Set loads pixels from GPU to system memory if necessary, which means that Set can be slow.

In the current implementation, successive calls of Set invokes loading pixels at most once, so this is efficient.

If the image is disposed, Set does nothing.

func (*Image) Size

func (i *Image) Size() (width, height int)

Size returns the size of the image.

func (*Image) SubImage

func (i *Image) SubImage(r image.Rectangle) image.Image

SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.

The returned value is always *ebiten.Image.

If the image is disposed, SubImage returns nil.

In the current Ebiten implementation, SubImage is available only as a rendering source.

type ImagePart

type ImagePart struct {
	Dst image.Rectangle
	Src image.Rectangle
}

ImagePart is sub image regions of the source and destination images.

Deprecated: (as of 1.1.0) Use SubImage instead.

type ImageParts

type ImageParts interface {
	Len() int
	Dst(i int) (x0, y0, x1, y1 int)
	Src(i int) (x0, y0, x1, y1 int)
}

ImageParts is sub image regions of the source and destination images.

Deprecated: (as of 1.5.0) Use SubImage instead.

type Key

type Key int

A Key represents a keyboard key. These keys represent pysical keys of US keyboard. For example, KeyQ represents Q key on US keyboards and ' (quote) key on Dvorak keyboards.

const (
	Key0            Key = Key(driver.Key0)
	Key1            Key = Key(driver.Key1)
	Key2            Key = Key(driver.Key2)
	Key3            Key = Key(driver.Key3)
	Key4            Key = Key(driver.Key4)
	Key5            Key = Key(driver.Key5)
	Key6            Key = Key(driver.Key6)
	Key7            Key = Key(driver.Key7)
	Key8            Key = Key(driver.Key8)
	Key9            Key = Key(driver.Key9)
	KeyA            Key = Key(driver.KeyA)
	KeyB            Key = Key(driver.KeyB)
	KeyC            Key = Key(driver.KeyC)
	KeyD            Key = Key(driver.KeyD)
	KeyE            Key = Key(driver.KeyE)
	KeyF            Key = Key(driver.KeyF)
	KeyG            Key = Key(driver.KeyG)
	KeyH            Key = Key(driver.KeyH)
	KeyI            Key = Key(driver.KeyI)
	KeyJ            Key = Key(driver.KeyJ)
	KeyK            Key = Key(driver.KeyK)
	KeyL            Key = Key(driver.KeyL)
	KeyM            Key = Key(driver.KeyM)
	KeyN            Key = Key(driver.KeyN)
	KeyO            Key = Key(driver.KeyO)
	KeyP            Key = Key(driver.KeyP)
	KeyQ            Key = Key(driver.KeyQ)
	KeyR            Key = Key(driver.KeyR)
	KeyS            Key = Key(driver.KeyS)
	KeyT            Key = Key(driver.KeyT)
	KeyU            Key = Key(driver.KeyU)
	KeyV            Key = Key(driver.KeyV)
	KeyW            Key = Key(driver.KeyW)
	KeyX            Key = Key(driver.KeyX)
	KeyY            Key = Key(driver.KeyY)
	KeyZ            Key = Key(driver.KeyZ)
	KeyApostrophe   Key = Key(driver.KeyApostrophe)
	KeyBackslash    Key = Key(driver.KeyBackslash)
	KeyBackspace    Key = Key(driver.KeyBackspace)
	KeyCapsLock     Key = Key(driver.KeyCapsLock)
	KeyComma        Key = Key(driver.KeyComma)
	KeyDelete       Key = Key(driver.KeyDelete)
	KeyDown         Key = Key(driver.KeyDown)
	KeyEnd          Key = Key(driver.KeyEnd)
	KeyEnter        Key = Key(driver.KeyEnter)
	KeyEqual        Key = Key(driver.KeyEqual)
	KeyEscape       Key = Key(driver.KeyEscape)
	KeyF1           Key = Key(driver.KeyF1)
	KeyF2           Key = Key(driver.KeyF2)
	KeyF3           Key = Key(driver.KeyF3)
	KeyF4           Key = Key(driver.KeyF4)
	KeyF5           Key = Key(driver.KeyF5)
	KeyF6           Key = Key(driver.KeyF6)
	KeyF7           Key = Key(driver.KeyF7)
	KeyF8           Key = Key(driver.KeyF8)
	KeyF9           Key = Key(driver.KeyF9)
	KeyF10          Key = Key(driver.KeyF10)
	KeyF11          Key = Key(driver.KeyF11)
	KeyF12          Key = Key(driver.KeyF12)
	KeyGraveAccent  Key = Key(driver.KeyGraveAccent)
	KeyHome         Key = Key(driver.KeyHome)
	KeyInsert       Key = Key(driver.KeyInsert)
	KeyKP0          Key = Key(driver.KeyKP0)
	KeyKP1          Key = Key(driver.KeyKP1)
	KeyKP2          Key = Key(driver.KeyKP2)
	KeyKP3          Key = Key(driver.KeyKP3)
	KeyKP4          Key = Key(driver.KeyKP4)
	KeyKP5          Key = Key(driver.KeyKP5)
	KeyKP6          Key = Key(driver.KeyKP6)
	KeyKP7          Key = Key(driver.KeyKP7)
	KeyKP8          Key = Key(driver.KeyKP8)
	KeyKP9          Key = Key(driver.KeyKP9)
	KeyKPAdd        Key = Key(driver.KeyKPAdd)
	KeyKPDecimal    Key = Key(driver.KeyKPDecimal)
	KeyKPDivide     Key = Key(driver.KeyKPDivide)
	KeyKPEnter      Key = Key(driver.KeyKPEnter)
	KeyKPEqual      Key = Key(driver.KeyKPEqual)
	KeyKPMultiply   Key = Key(driver.KeyKPMultiply)
	KeyKPSubtract   Key = Key(driver.KeyKPSubtract)
	KeyLeft         Key = Key(driver.KeyLeft)
	KeyLeftBracket  Key = Key(driver.KeyLeftBracket)
	KeyMenu         Key = Key(driver.KeyMenu)
	KeyMinus        Key = Key(driver.KeyMinus)
	KeyNumLock      Key = Key(driver.KeyNumLock)
	KeyPageDown     Key = Key(driver.KeyPageDown)
	KeyPageUp       Key = Key(driver.KeyPageUp)
	KeyPause        Key = Key(driver.KeyPause)
	KeyPeriod       Key = Key(driver.KeyPeriod)
	KeyPrintScreen  Key = Key(driver.KeyPrintScreen)
	KeyRight        Key = Key(driver.KeyRight)
	KeyRightBracket Key = Key(driver.KeyRightBracket)
	KeyScrollLock   Key = Key(driver.KeyScrollLock)
	KeySemicolon    Key = Key(driver.KeySemicolon)
	KeySlash        Key = Key(driver.KeySlash)
	KeySpace        Key = Key(driver.KeySpace)
	KeyTab          Key = Key(driver.KeyTab)
	KeyUp           Key = Key(driver.KeyUp)
	KeyAlt          Key = Key(driver.KeyReserved0)
	KeyControl      Key = Key(driver.KeyReserved1)
	KeyShift        Key = Key(driver.KeyReserved2)
	KeyMax          Key = KeyShift
)

Keys.

func (Key) String

func (k Key) String() string

String returns a string representing the key.

If k is an undefined key, String returns an empty string.

type MouseButton

type MouseButton int

A MouseButton represents a mouse button.

const (
	MouseButtonLeft   MouseButton = MouseButton(driver.MouseButtonLeft)
	MouseButtonRight  MouseButton = MouseButton(driver.MouseButtonRight)
	MouseButtonMiddle MouseButton = MouseButton(driver.MouseButtonMiddle)
)

MouseButtons

type Shader

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

Shader represents a compiled shader program.

For the details about the shader, see https://ebiten.org/documents/shader.html.

func NewShader

func NewShader(src []byte) (*Shader, error)

NewShader compiles a shader program in the shading language Kage, and retruns the result.

If the compilation fails, NewShader returns an error.

For the details about the shader, see https://ebiten.org/documents/shader.html.

func (*Shader) Dispose

func (s *Shader) Dispose()

Dispose disposes the shader program. After disposing, the shader is no longer available.

type Touch

type Touch interface {
	// ID returns an identifier for one stroke.
	ID() int

	// Position returns the position of the touch.
	Position() (x, y int)
}

Touch represents a touch.

Deprecated: (as of 1.7.0). Use TouchPosition instead.

func Touches

func Touches() []Touch

Touches returns the current touches.

Deprecated: (as of 1.7.0) Use TouchIDs instead.

type Vertex

type Vertex struct {
	// DstX and DstY represents a point on a destination image.
	DstX float32
	DstY float32

	// SrcX and SrcY represents a point on a source image.
	// Be careful that SrcX/SrcY coordinates are on the image's bounds.
	// This means that a left-upper point of a sub-image might not be (0, 0).
	SrcX float32
	SrcY float32

	// ColorR/ColorG/ColorB/ColorA represents color scaling values.
	// 1 means the original source image color is used.
	// 0 means a transparent color is used.
	ColorR float32
	ColorG float32
	ColorB float32
	ColorA float32
}

Vertex represents a vertex passed to DrawTriangles.