feat: keep working on Tags.

cmd/test/debug.go

@@ -67,6 +67,11 @@ func (d *Debug) Draw(c Context) *gg.Drawing {
 
 		"GetAbsWinSize(...) = ",
 		c.Engine().GetAbsWinSize(), "\n",
+
+		"ConnectedTriangleAmount = ",
+		len(c.Engine().Objects().FindByTags(
+			TagTriangle, TagConnectedToPlayer,
+		)), "\n",
 	)
 
 	return nil

cmd/test/main.go

@@ -26,6 +26,12 @@ const (
 	LayerLowest
 )
 
+const (
+	TagPlayer gg.Tag = gg.TagLast + 1 + iota
+	TagConnectedToPlayer
+	TagTriangle
+)
+
 const (
 	Stand ax.AnimationID = iota
 	Walk

cmd/test/trianlge.go

@@ -10,6 +10,7 @@ var (
 	counter int
 )
 
+
 type Tri struct {
 	ox.DrawablePolygon
 	Spawned bool
@@ -32,6 +33,16 @@ func NewTri(t *ox.Transform) *Tri {
 	return ret
 }
 
+func (t *Tri) GetTags(c Context) gg.TagMap {
+	tags := gg.TagMap{
+		TagTriangle: struct{}{},
+	}
+	if t.IsConnected() {
+		tags[TagConnectedToPlayer] = struct{}{}
+	}
+	return tags
+}
+
 func (t *Tri) OnStart(c Context) {
 	log.Println("added a tri")
 }

engine.go

@@ -323,22 +323,25 @@ func (e *engine) Update() error {
 	// but for it is simple enough.
 
 	events := e.updateEvents()
+
 	c := Context{
 		engine: eng,
 		events: events,
 	}
-	for _, object := range e.objects.store {
+
-		if object == nil {
+	// Should think of the order?
-			continue
+	e.objects.updateTags(c)
-		}
+	e.objects.updateObjects(c)
-		object.OnUpdate(c)
-	}
 
 	e.lastTime = time.Now()
 	e.frame++
 	return nil
 }
 
+func (e *Engine) Objects() *Objects {
+	return e.objects
+}
+
 
 var (
 	fullPageIndexes = func() [MaxVertices]uint16 {

object.go

@@ -8,7 +8,7 @@ type Object interface {
 	OnStart(Context)
 	OnUpdate(Context)
 	OnDelete(Context)
-	GetTags() TagMap
+	GetTags(Context) TagMap
 }
 
 

objects.go

@@ -1,5 +1,7 @@
 package gg
 
+type ObjectMap map[Object] struct{}
+
 // The structure to store objects
 // with O(1) add, remove and search operations.
 type Objects struct {
@@ -9,6 +11,8 @@ type Objects struct {
 	// Find index by Object.
 	searchMap map[Object] int
 
+	tagMap map[Tag] ObjectMap
+
 	// Available nil values in the store.
 	freeIndexes []int
 }
@@ -16,6 +20,7 @@ type Objects struct {
 func NewObjects() *Objects {
 	ret := &Objects{}
 	ret.searchMap = map[Object] int {}
+	ret.tagMap = map[Tag]ObjectMap{}
 	return ret
 }
 
@@ -56,3 +61,64 @@ func (objects *Objects) remove(object Object) bool {
 	return true
 }
 
+func (objects *Objects) FindByTags(
+	t Tag, rest ...Tag,
+) []Object {
+	tagMap := objects.tagMap
+	objectMap := tagMap[t]
+	retMap := map[Object]struct{}{}
+	for object := range objectMap {
+		retMap[object] = struct{}{}
+	}
+
+	for _, tag := range rest {
+		m, ok := tagMap[tag]
+		if !ok {
+			continue
+		}
+		for object := range m {
+			_, ok := m[object]
+			if !ok {
+				delete(retMap, object)
+			}
+		}
+	}
+
+	ret := []Object{}
+	for object := range retMap {
+		ret = append(ret, object)
+	}
+
+	return ret
+}
+
+func (objects *Objects) updateObjects(c Context){
+	for _, object := range objects.store {
+		if object == nil {
+			continue
+		}
+		object.OnUpdate(c)
+	}
+}
+
+func (objects *Objects) updateTags(c Context) {
+	tagMap := objects.tagMap
+	updateMap := make(map[Tag]ObjectMap, len(tagMap))
+
+	for _, object := range objects.store {
+		tags := object.GetTags(c)
+		for tag := range tags {
+			tm, ok := updateMap[tag]
+			if ok {
+				tm[object] = struct{}{}
+			} else {
+				updateMap[tag] = ObjectMap{
+					object: struct{}{},
+				}
+			}
+
+		}
+	}
+	objects.tagMap = updateMap
+}
+

ox/object.go

@@ -13,7 +13,11 @@ type BeherImpl struct{}
 func (o BeherImpl) OnStart(c gg.Context) {}
 func (o BeherImpl) OnUpdate(c gg.Context) {}
 func (o BeherImpl) OnDelete(c gg.Context) {}
-func (o BeherImpl) GetTags() gg.TagMap {return nil}
+func (o BeherImpl) GetTags(
+	c gg.Context,
+) gg.TagMap {
+	return nil
+}
 
 // The standard empty implementation
 // of the Object interface to embed

tag.go

@@ -3,3 +3,14 @@ package gg
 type Tag int64
 type TagMap map[Tag] struct{}
 
+const (
+	_ Tag = iota
+	TagUI
+
+	// The constant is used
+	// to make after it custom tags
+	// so they do not cross with the builtins
+	// like "TagUI".
+	TagLast
+)
+