Dango

Dango is a collection of functions that can be used with Ebitengine

data.go - FS

embedded file system

Commonly used function to load files from embedded file system Example:

import "github.com/iatearock/dango"
//go:embed assets/*
var data embed.FS
vfs = dango.NewFS(data)

// example usage
img, err := vfs.GetImage("assets/images/red.png") // *ebiten.Image
ff, err := vfs.GetFontFace("assets/font/red.ttf") // font.Face
str, err := vfs.GetCSV("assets/csv/red.csv") // [][]string
byte, err := vfs.ReadFile("assets/csv/red.txt") // []byte

camera

Adopted from ebiten camera example: https://github.com/hajimehoshi/ebiten/tree/main/examples/camera

cam := &dango.Camera{}  // setup camera 
cam.SetViewPort(w, h)
cam.Update() // update when position/rotation/zoom/viewport change

spriteOp := &ebiten.DrawImageOptions{}  // init options, and then apply sprite's transformation to spriteOp
spriteOP.GeoM.Concat(cam.GeoM()) // multiply sprite's matrix to camera matrix
screen.Draw(sprite, spriteOp)

screenX, screenY := cam.WorldToScreen(worldX, worldY) // transform coordinates

scene

Scene manager adopted from ebiten Block example Handle transition between scenes that implement Update() and Draw(*ebiten.Image)

id

Simple unique id generator, concurrency safe, I think.

bitmasks

bits.go provide bitmask functions with mutex lock Example:

const {
	s1 = 1 << iota
	s2
	s3
    s4
}

b = NewBits()
b.Set(s2|s3)
b.Has(s1|s2)  // true, matched any bit
b.HasAll(s1|s2) // false, need to match all bits

Neon light

Add neon light effect to an image

Neon adds color c within light pixels away from any pixels with 255 for alpha channel. Gaussian blur is applied with sqaure of width blur, and sigma as Gaussian standard deviation If origin, original image is draw on top of new image If resize, new image will be larger due to Gaussian effect on the edge

img := LoadPNG("input.png") // import a png file to *image.RGBA

d := 2 // add colour up to 2 pixels aways, from existing pixel with 255 in alpha channel
k := 3 // 3x3 kernal size for Gaussian blurring
s := 1 // standard deviation for Gaussian kernal
yellow := color.RGBA{255,255,0,255}
origin := true // draw original image on top of the result
resize := false // remove edge pixel produced by the Gaussin kernal, i.e. false to return same image size as the input

dango.Neon(img, d, k, s, yellow, origin, resize)

Input image: Result image: