doodle/pkg/uix/actor.go

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package uix
import (
"errors"
"fmt"
"git.kirsle.net/apps/doodle/lib/render"
"git.kirsle.net/apps/doodle/pkg/doodads"
"git.kirsle.net/apps/doodle/pkg/level"
uuid "github.com/satori/go.uuid"
)
// Actor is an object that marries together the three things that make a
// Doodad instance "tick" while inside a Canvas:
//
// - uix.Actor is a doodads.Drawing so it fulfills doodads.Actor to be a
// dynamic object during gameplay.
// - It has a pointer to the level.Actor indicating its static level data
// as defined in the map: its spawn coordinate and configuration.
// - A uix.Canvas that can present the actor's graphics to the screen.
type Actor struct {
doodads.Drawing
Actor *level.Actor
Canvas *Canvas
activeLayer int // active drawing frame for display
flagDestroy bool // flag the actor for destruction
}
// NewActor sets up a uix.Actor.
// If the id is blank, a new UUIDv4 is generated.
func NewActor(id string, levelActor *level.Actor, doodad *doodads.Doodad) *Actor {
if id == "" {
id = uuid.Must(uuid.NewV4()).String()
}
size := int32(doodad.Layers[0].Chunker.Size)
can := NewCanvas(int(size), false)
can.Name = id
// TODO: if the Background is render.Invisible it gets defaulted to
// White somewhere and the Doodad masks the level drawing behind it.
can.SetBackground(render.RGBA(0, 0, 1, 0))
can.LoadDoodad(doodad)
can.Resize(render.NewRect(size, size))
actor := &Actor{
Drawing: doodads.NewDrawing(id, doodad),
Actor: levelActor,
Canvas: can,
}
// Give the Canvas a pointer to its (parent) Actor so it can draw its debug
// label and show the World Position of the actor within the world.
can.actor = actor
return actor
}
// LayerCount returns the number of layers in this actor's drawing.
func (a *Actor) LayerCount() int {
return len(a.Doodad.Layers)
}
// ShowLayer sets the actor's ActiveLayer to the index given.
func (a *Actor) ShowLayer(index int) error {
if index < 0 {
return errors.New("layer index must be 0 or greater")
} else if index > len(a.Doodad.Layers) {
return fmt.Errorf("layer %d out of range for doodad's layers", index)
}
a.activeLayer = index
a.Canvas.Load(a.Doodad.Palette, a.Doodad.Layers[index].Chunker)
return nil
}
// Destroy deletes the actor from the running level.
func (a *Actor) Destroy() {
a.flagDestroy = true
}