Inventory System for Level Actors

* Added an inventory system for actors as a replacement to the arbitrary
  key/value data store. Colored keys now add themselves to the player's
  inventory, and colored doors check the inventory.
* Inventory is a map[string]int between doodad filenames
  (red-key.doodad) and quantity (0 for key items/unlimited qty).
* API methods to add and remove inventory.
* Items HUD appears in Play Mode in lower-left corner showing doodad
  sprites of all the items in the Player's inventory.

dev-assets/doodads/doors/colored-door.js

@@ -1,6 +1,7 @@
 
 function main() {
 	var color = Self.Doodad.Tag("color");
+	var keyname = "key-" + color + ".doodad";
 
 	// Layers in the doodad image.
 	var layer = {
@@ -34,8 +35,9 @@ function main() {
 				return;
 			}
 
-			var data = e.Actor.GetData("key:" + color);
-			if (data === "") {
+			// Do they have our key?
+			var hasKey = e.Actor.HasItem(keyname) >= 0;
+			if (!hasKey) {
 				// Door is locked.
 				return false;
 			}

dev-assets/doodads/doors/keys.js

@@ -2,7 +2,9 @@ function main() {
 	var color = Self.Doodad.Tag("color");
 
 	Events.OnCollide(function(e) {
-		e.Actor.SetData("key:" + color, "true");
-		Self.Destroy();
+		if (e.Settled) {
+			e.Actor.AddItem(Self.Doodad.Filename, 0);
+			Self.Destroy();
+		}
 	})
 }

pkg/play_inventory.go

@@ -0,0 +1,121 @@
+package doodle
+
+import (
+	"git.kirsle.net/apps/doodle/pkg/balance"
+	"git.kirsle.net/apps/doodle/pkg/doodads"
+	"git.kirsle.net/apps/doodle/pkg/uix"
+	"git.kirsle.net/go/render"
+	"git.kirsle.net/go/ui"
+)
+
+// setupInventoryHud configures the Inventory HUD.
+func (s *PlayScene) setupInventoryHud() {
+	s.invenFrame = ui.NewFrame("Inventory")
+	s.invenDoodads = map[string]*uix.Canvas{}
+	s.invenFrame.Configure(ui.Config{
+		BorderStyle: ui.BorderRaised,
+		BorderSize:  2,
+		Background:  render.RGBA(128, 128, 128, 60),
+	})
+
+	// Items label.
+	label := ui.NewLabel(ui.Label{
+		Text: "Items:",
+		Font: balance.LabelFont,
+	})
+	label.Compute(s.d.Engine)
+
+	// Configure the label tall enough to cover typical 32x32 item doodads.
+	// This pushes the Frame height tall enough.
+	label.Configure(ui.Config{
+		Height: 36,
+		Width:  label.Size().W + 2,
+	})
+	s.invenFrame.Pack(label, ui.Pack{
+		Side: ui.W,
+		PadX: 2,
+		PadY: 4,
+	})
+
+	// Add the inventory frame to the screen frame.
+	s.screen.Place(s.invenFrame, ui.Place{
+		Left:   40,
+		Bottom: 40,
+	})
+
+	// Hide inventory if empty.
+	if len(s.invenItems) == 0 {
+		s.invenFrame.Hide()
+	}
+}
+
+// computeInventory adjusts the inventory HUD when the player's inventory changes.
+func (s *PlayScene) computeInventory() {
+	items := s.Player.ListItems()
+	if len(items) != len(s.invenItems) {
+		// Inventory has changed! See which doodads we have
+		// and which we need to load.
+		var seen = map[string]interface{}{}
+		for _, filename := range items {
+			seen[filename] = nil
+
+			if _, ok := s.invenDoodads[filename]; !ok {
+				// Cache miss. Load the doodad here.
+				doodad, err := doodads.LoadFile(filename)
+				if err != nil {
+					s.d.Flash("Inventory item '%s' error: %s", filename, err)
+					continue
+				}
+
+				canvas := uix.NewCanvas(doodad.ChunkSize(), false)
+				canvas.LoadDoodad(doodad)
+				canvas.Resize(render.NewRect(
+					doodad.ChunkSize(), doodad.ChunkSize(),
+				))
+				s.invenFrame.Pack(canvas, ui.Pack{
+					Side: ui.W,
+
+					// TODO: work around a weird padding bug. item had too
+					// tall a top margin when added to the inventory frame!
+					PadX: 8,
+				})
+				s.invenDoodads[filename] = canvas
+			}
+
+			s.invenDoodads[filename].Show()
+		}
+
+		// Hide any doodad that used to be in the inventory but now is not.
+		for filename, canvas := range s.invenDoodads {
+			if _, ok := seen[filename]; !ok {
+				canvas.Hide()
+			}
+		}
+
+		// Recompute the size of the inventory frame.
+		// TODO: this works around a bug in ui.Frame, at the bottom of
+		// compute_packed, a frame Resize's itself to fit the children but this
+		// trips the "manually set size" boolean... packing more items after a
+		// computer doesn't resize the frame. So here, we resize-auto it to
+		// reset that boolean so the next compute, picks the right size.
+		s.invenFrame.Configure(ui.Config{
+			AutoResize: true,
+			Width:      1,
+			Height:     1,
+		})
+		s.invenFrame.Compute(s.d.Engine)
+
+		// If we removed all items, hide the frame.
+		if len(items) == 0 {
+			s.invenFrame.Hide()
+		} else {
+			s.invenFrame.Show()
+		}
+
+		// Cache the item list so we don't run the above logic every single tick.
+		s.invenItems = items
+	}
+
+	// Compute the inventory frame so it positions and wraps the items.
+	s.screen.Compute(s.d.Engine)
+}

pkg/play_scene.go

@@ -31,6 +31,7 @@ type PlayScene struct {
 
 	// UI widgets.
 	supervisor *ui.Supervisor
+	screen     *ui.Frame // A window sized invisible frame to position UI elements.
 	editButton *ui.Button
 
 	// The alert box shows up when the level goal is reached and includes
@@ -53,6 +54,11 @@ type PlayScene struct {
 	antigravity       bool // Cheat: disable player gravity
 	noclip            bool // Cheat: disable player clipping
 	playerJumpCounter int  // limit jump length
+
+	// Inventory HUD. Impl. in play_inventory.go
+	invenFrame   *ui.Frame
+	invenItems   []string // item list
+	invenDoodads map[string]*uix.Canvas
 }
 
 // Name of the scene.
@@ -66,6 +72,10 @@ func (s *PlayScene) Setup(d *Doodle) error {
 	s.scripting = scripting.NewSupervisor()
 	s.supervisor = ui.NewSupervisor()
 
+	// Create an invisible 'screen' frame for UI elements to use for positioning.
+	s.screen = ui.NewFrame("Screen")
+	s.screen.Resize(render.NewRect(d.width, d.height))
+
 	// Level Exit handler.
 	s.SetupAlertbox()
 	s.scripting.OnLevelExit(func() {
@@ -112,6 +122,9 @@ func (s *PlayScene) Setup(d *Doodle) error {
 	})
 	s.supervisor.Add(s.editButton)
 
+	// Set up the inventory HUD.
+	s.setupInventoryHud()
+
 	// Initialize the drawing canvas.
 	s.drawing = uix.NewCanvas(balance.ChunkSize, false)
 	s.drawing.Name = "play-canvas"
@@ -382,6 +395,9 @@ func (s *PlayScene) Loop(d *Doodle, ev *event.State) error {
 		if err := s.drawing.Loop(ev); err != nil {
 			log.Error("Drawing loop error: %s", err.Error())
 		}
+
+		// Update the inventory HUD.
+		s.computeInventory()
 	}
 
 	return nil
@@ -398,6 +414,10 @@ func (s *PlayScene) Draw(d *Doodle) error {
 	// Draw out bounding boxes.
 	d.DrawCollisionBox(s.Player)
 
+	// Draw the UI screen and any widgets that attached to it.
+	s.screen.Compute(d.Engine)
+	s.screen.Present(d.Engine, render.Origin)
+
 	// Draw the Edit button.
 	var (
 		canSize = s.drawing.Size()

pkg/uix/actor.go

@@ -3,6 +3,8 @@ package uix
 import (
 	"errors"
 	"fmt"
+	"sort"
+	"sync"
 
 	"git.kirsle.net/apps/doodle/pkg/doodads"
 	"git.kirsle.net/apps/doodle/pkg/level"
@@ -33,12 +35,17 @@ type Actor struct {
 	isMobile   bool // Mobile character, such as the player or an enemy
 	noclip     bool // Disable collision detection
 	hitbox     render.Rect
-	data       map[string]string
+	inventory  map[string]int    // item inventory. doodad name -> quantity, 0 for key item.
+	data       map[string]string // arbitrary key/value store. DEPRECATED ??
 
 	// Animation variables.
 	animations        map[string]*Animation
 	activeAnimation   *Animation
 	animationCallback otto.Value
+
+	// Mutex.
+	muInventory sync.RWMutex
+	muData      sync.RWMutex
 }
 
 // NewActor sets up a uix.Actor.
@@ -64,6 +71,7 @@ func NewActor(id string, levelActor *level.Actor, doodad *doodads.Doodad) *Actor
 		Actor:      levelActor,
 		Canvas:     can,
 		animations: map[string]*Animation{},
+		inventory:  map[string]int{},
 	}
 
 	// Give the Canvas a pointer to its (parent) Actor so it can draw its debug
@@ -96,6 +104,87 @@ func (a *Actor) SetNoclip(v bool) {
 	a.noclip = v
 }
 
+// AddItem adds an item doodad to the actor's inventory.
+// Item name is usually the doodad filename.
+func (a *Actor) AddItem(itemName string, quantity int) {
+	a.muInventory.Lock()
+	a.inventory[itemName] = quantity
+	a.muInventory.Unlock()
+}
+
+// RemoveItem removes a quantity of an item from the actor's inventory.
+//
+// Provide a quantity of 0 to remove the item completely.
+// Otherwise provides a number greater than zero and you will subtract this
+// quantity from the item. If the item then is at <= zero, it is removed from
+// inventory.
+func (a *Actor) RemoveItem(itemName string, quantity int) bool {
+	a.muInventory.RLock()
+	defer a.muInventory.RUnlock()
+
+	if _, ok := a.inventory[itemName]; ok {
+		// If quantity is zero, remove the item entirely.
+		if quantity <= 0 {
+			delete(a.inventory, itemName)
+		} else {
+			// Subtract the quantity from inventory. If we have run down to
+			// zero left, remove the item entirely.
+			a.inventory[itemName] -= quantity
+			if a.inventory[itemName] <= 0 {
+				delete(a.inventory, itemName)
+			}
+		}
+		return true
+	}
+	return false
+}
+
+// HasItem checks the actor's inventory for the item and returns the quantity.
+//
+// A return value of -1 means the item was not found.
+// The value 0 indicates a key item (one with no quantity).
+// Values >= 1 would be consumable items.
+func (a *Actor) HasItem(itemName string) int {
+	a.muInventory.RLock()
+	defer a.muInventory.RUnlock()
+
+	if quantity, ok := a.inventory[itemName]; ok {
+		return quantity
+	}
+	return -1
+}
+
+// ListItems returns a sorted list of the items in the actor's inventory.
+func (a *Actor) ListItems() []string {
+	a.muInventory.RLock()
+	defer a.muInventory.RUnlock()
+
+	var (
+		result = make([]string, len(a.inventory))
+		i      = 0
+	)
+	for k := range a.inventory {
+		result[i] = k
+		i++
+	}
+
+	sort.Strings(result)
+	return result
+}
+
+// Inventory returns a copy of the actor's inventory struct.
+func (a *Actor) Inventory() map[string]int {
+	a.muInventory.RLock()
+	defer a.muInventory.RUnlock()
+
+	var result = map[string]int{}
+	for k, v := range a.inventory {
+		result[k] = v
+	}
+
+	return result
+}
+
 // GetBoundingRect gets the bounding box of the actor's doodad.
 func (a *Actor) GetBoundingRect() render.Rect {
 	return doodads.GetBoundingRect(a)
@@ -121,7 +210,10 @@ func (a *Actor) SetData(key, value string) {
 	if a.data == nil {
 		a.data = map[string]string{}
 	}
+
+	a.muData.Lock()
 	a.data[key] = value
+	a.muData.Unlock()
 }
 
 // GetData gets an arbitrary field from the actor's K/V storage.
@@ -132,7 +224,10 @@ func (a *Actor) GetData(key string) string {
 		return ""
 	}
 
+	a.muData.RLock()
 	v, _ := a.data[key]
+	a.muData.RUnlock()
+
 	return v
 }