experiment continues

engine/game.go

@@ -13,6 +13,8 @@ import (
 	"github.com/hajimehoshi/ebiten/v2"
 )
 
+const gameDoesEverything = false
+
 var _ interface {
 	Disabler
 	Hider
@@ -71,15 +73,57 @@ func (g *Game) Draw(screen *ebiten.Image) {
 	if g.Hidden {
 		return
 	}
-	//g.Root.Draw(screen, ebiten.DrawImageOptions{})
+	if !gameDoesEverything {
+		g.Root.Draw(screen, ebiten.DrawImageOptions{})
+	}
+	if gameDoesEverything {
+		hidden := map[interface{}]bool{
+			g: false, // g.Hidden checked above
+		}
+		transform := map[interface{}]ebiten.DrawImageOptions{
+			g: {},
+		}
 		// draw everything
 		for _, d := range g.drawList {
+			// directly hidden?
 			if h, ok := d.(Hider); ok && h.IsHidden() {
+				hidden[d] = true
 				continue
 			}
+			// hidden by parent?
+			// walk up the parents to find the lowest known
+			hid := false
+			stack := []interface{}{d}
+			for p := g.par[d]; p != nil; p = g.par[p] {
+				if h, found := hidden[p]; found {
+					hid = h
+					break
+				}
+				stack = append(stack, p)
+			}
+			// unwind the stack, setting known values
+			for len(stack) > 0 {
+				l1 := len(stack) - 1
+				p := stack[l1]
+				stack = stack[:l1]
+				if h, ok := p.(Hider); ok {
+					hid = hid || h.IsHidden()
+					hidden[p] = hid
+				}
+			}
+
+			// now...skip if hidden
+			if hid {
+				continue
+			}
+
+			if t, ok := d.(Transformer); ok {
+				transform[t] = t.Transform() // concatted with parent transform...
+			}
 			d.Draw(screen, ebiten.DrawImageOptions{})
 		}
 	}
+}
 
 // Layout returns the configured screen width/height.
 func (g *Game) Layout(outsideWidth, outsideHeight int) (w, h int) {
@@ -95,7 +139,7 @@ func (g *Game) Update() error {
 	if err := g.Root.Update(); err != nil {
 		return err
 	}
-
+	if gameDoesEverything {
 		// sort the draw list (yes, on every frame)
 		sort.Stable(g.drawList)
 		// slice out any tombstones
@@ -104,6 +148,7 @@ func (g *Game) Update() error {
 				g.drawList = g.drawList[:i]
 			}
 		}
+	}
 	return nil
 }
 

engine/interface.go

@@ -26,6 +26,7 @@ var (
 	ScannerType        = reflect.TypeOf((*Scanner)(nil)).Elem()
 	ScenerType         = reflect.TypeOf((*Scener)(nil)).Elem()
 	SaverType          = reflect.TypeOf((*Saver)(nil)).Elem()
+	TransformerType    = reflect.TypeOf((*Transformer)(nil)).Elem()
 	UpdaterType        = reflect.TypeOf((*Updater)(nil)).Elem()
 
 	// Behaviours lists all the behaviours that can be queried with Game.Query.
@@ -44,6 +45,7 @@ var (
 		ScannerType,
 		ScenerType,
 		SaverType,
+		TransformerType,
 		UpdaterType,
 	}
 )
@@ -162,6 +164,11 @@ type Saver interface {
 	Save() error
 }
 
+// Transformer components can transform their child components.
+type Transformer interface {
+	Transform() ebiten.DrawImageOptions
+}
+
 // Updater components can update themselves. Update is called repeatedly.
 // Each component is responsible for calling Update on its child components
 // (so that disabling the parent prevents updates to the children, etc).