A package implementing various graphics primitives like Sprite for Ebitengine.
It works the best in combination with gscene package, but can be used without it.
Graphical objects list:
- Sprite
- Line, DottedLine, Texture Line
- Circle (supports dashed style)
- Rect
- Label
- Container
- Canvas
- Easier shader-based drawing (ShaderObject)
Missing some graphical object? Tell us about it.
It also supports a basic camera and layers implementation.
go get github.com/quasilyte/ebitengine-graphics
The most useful type of this package is Sprite
, but it's tricky to demonstrate its usage without assets. This is a quick start section, it's intended to be as slim as possible.
You can use this library without gscene:
package main
import (
"github.com/hajimehoshi/ebiten/v2"
graphics "github.com/quasilyte/ebitengine-graphics"
"github.com/quasilyte/gmath"
)
func main() {
ebiten.SetWindowSize(640, 480)
if err := ebiten.RunGame(newExampleGame()); err != nil {
panic(err)
}
}
type exampleGame struct {
pos gmath.Vec
initialized bool
objects []drawable
}
type drawable interface {
Draw(screen *ebiten.Image)
}
func newExampleGame() *exampleGame {
return &exampleGame{
pos: gmath.Vec{X: 32, Y: 32},
}
}
func (g *exampleGame) Layout(outsideWidth, outsideHeight int) (int, int) {
return 640, 480
}
func (g *exampleGame) Draw(screen *ebiten.Image) {
for _, o := range g.objects {
o.Draw(screen)
}
}
func (g *exampleGame) Update() error {
if !g.initialized {
g.Init()
g.initialized = true
}
g.pos = g.pos.Add(gmath.Vec{X: 1, Y: 2})
return nil
}
func (g *exampleGame) Init() {
{
from := gmath.Pos{Base: &g.pos}
to := gmath.Pos{Offset: gmath.Vec{X: 128, Y: 64}}
l := graphics.NewLine(from, to)
l.SetWidth(2)
l.SetColorScale(graphics.ColorScaleFromRGBA(200, 100, 100, 255))
g.objects = append(g.objects, l)
}
{
r := graphics.NewRect(32, 32)
r.Pos.Base = &g.pos
r.SetFillColorScale(graphics.RGB(0xAABB00))
r.SetOutlineColorScale(graphics.RGB(0x0055ff))
r.SetOutlineWidth(2)
g.objects = append(g.objects, r)
}
}
With gscene
it's even easier (showing only relevant part):
func (c *exampleController) Init(scene *gscene.SimpleRootScene) {
{
from := gmath.Pos{Base: &g.pos}
to := gmath.Pos{Offset: gmath.Vec{X: 128, Y: 64}}
l := graphics.NewLine(from, to)
l.SetWidth(2)
l.SetColorScale(graphics.ColorScaleFromRGBA(200, 100, 100, 255))
scene.AddGraphics(l)
}
{
r := graphics.NewRect(32, 32)
r.Pos.Base = &g.pos
r.SetFillColorScale(graphics.RGB(0xAABB00))
r.SetOutlineColorScale(graphics.RGB(0x0055ff))
r.SetOutlineWidth(2)
scene.AddGraphics(r)
}
}
Note that we can add the graphical object directly to the scene. The scene will manage their Draw
calls as well as their lifetimes (based on graphical objects being disposed or not).