77 lines
1.8 KiB
Go
77 lines
1.8 KiB
Go
package engine
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import (
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"encoding/gob"
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"fmt"
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"image"
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"drjosh.dev/gurgle/geom"
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"github.com/hajimehoshi/ebiten/v2"
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)
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// Ensure Sprite satisfies interfaces.
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var _ interface {
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BoundingBoxer
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Drawer
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Scanner
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Transformer
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Updater
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} = &Sprite{}
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func init() {
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gob.Register(&Sprite{})
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}
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// Sprite combines an Actor with the ability to Draw from a single spritesheet.
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type Sprite struct {
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Actor Actor
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DrawOffset image.Point
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Hides
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Sheet Sheet
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anim *Anim
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}
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// BoundingBox forwards the call to Actor.
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func (s *Sprite) BoundingBox() geom.Box { return s.Actor.BoundingBox() }
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// Draw draws the current cell to the screen.
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func (s *Sprite) Draw(screen *ebiten.Image, opts *ebiten.DrawImageOptions) {
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screen.DrawImage(s.Sheet.SubImage(s.anim.Cell()), opts)
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}
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// Scan returns the Actor and the Sheet.
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func (s *Sprite) Scan() []interface{} {
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return []interface{}{
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&s.Actor,
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&s.Sheet,
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}
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}
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// SetAnim sets the Anim to use for the sprite. If it is not the same as the
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// one currently set, it resets the new anim.
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func (s *Sprite) SetAnim(a *Anim) {
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if s.anim != a {
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a.Reset()
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}
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s.anim = a
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}
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func (s *Sprite) String() string {
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return fmt.Sprintf("Sprite@%v", s.Actor.Pos)
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}
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// Transform returns a translation by the DrawOffset and Actor.Pos projected
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func (s *Sprite) Transform() (opts ebiten.DrawImageOptions) {
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opts.GeoM.Translate(geom.CFloat(
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// Reaching into Actor for a reference to Game so I don't have to
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// implement Prepare in this file, but writing this long comment
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// providing exposition...
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s.Actor.game.Projection.Project(s.Actor.Pos).Add(s.DrawOffset),
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))
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return opts
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}
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// Update updates the Sprite's anim. anim can change a bit so we don't tell Game
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// about it, but that means it must be updated manually.
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func (s *Sprite) Update() error { return s.anim.Update() }
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