From c1d5033eb0472571f94c323555eab69649003234 Mon Sep 17 00:00:00 2001
From: bloeys <bloeys@outlook.com>
Date: Fri, 6 Oct 2023 03:52:43 +0400
Subject: [PATCH] Separate components from entity

---
 entity/base_comp.go |  2 +-
 entity/comp.go      | 22 +++++++++++++++-------
 entity/entity.go    | 10 +---------
 entity/registry.go  |  7 +------
 main.go             |  7 ++++---
 5 files changed, 22 insertions(+), 26 deletions(-)

diff --git a/entity/base_comp.go b/entity/base_comp.go
index 8ca1d4b..e9892aa 100755
--- a/entity/base_comp.go
+++ b/entity/base_comp.go
@@ -8,7 +8,7 @@ type BaseComp struct {
 	Entity *Entity
 }
 
-func (b *BaseComp) base() {
+func (b *BaseComp) baseComp() {
 }
 
 func (b *BaseComp) Init(parent *Entity) {
diff --git a/entity/comp.go b/entity/comp.go
index 4f2061b..4a22dc8 100755
--- a/entity/comp.go
+++ b/entity/comp.go
@@ -5,7 +5,7 @@ import "github.com/bloeys/nmage/assert"
 type Comp interface {
 	// This ensures that implementors of the Comp interface
 	// always embed BaseComp
-	base()
+	baseComp()
 
 	Name() string
 	Init(parent *Entity)
@@ -13,15 +13,23 @@ type Comp interface {
 	Destroy()
 }
 
-func AddComp[T Comp](e *Entity, c T) {
+func NewCompContainer() CompContainer {
+	return CompContainer{Comps: []Comp{}}
+}
 
-	assert.T(!HasComp[T](e), "Entity with id '%v' already has component of type '%T'", e.ID, c)
+type CompContainer struct {
+	Comps []Comp
+}
 
-	e.Comps = append(e.Comps, c)
+func AddComp[T Comp](e *Entity, cc *CompContainer, c T) {
+
+	assert.T(!HasComp[T](cc), "Entity with id '%v' already has component of type '%T'", e.ID, c)
+
+	cc.Comps = append(cc.Comps, c)
 	c.Init(e)
 }
 
-func HasComp[T Comp](e *Entity) bool {
+func HasComp[T Comp](e *CompContainer) bool {
 
 	for i := 0; i < len(e.Comps); i++ {
 
@@ -34,7 +42,7 @@ func HasComp[T Comp](e *Entity) bool {
 	return false
 }
 
-func GetComp[T Comp](e *Entity) (out T) {
+func GetComp[T Comp](e *CompContainer) (out T) {
 
 	for i := 0; i < len(e.Comps); i++ {
 
@@ -48,7 +56,7 @@ func GetComp[T Comp](e *Entity) (out T) {
 }
 
 // DestroyComp calls Destroy on the component and then removes it from the entities component list
-func DestroyComp[T Comp](e *Entity) {
+func DestroyComp[T Comp](e *CompContainer) {
 
 	for i := 0; i < len(e.Comps); i++ {
 
diff --git a/entity/entity.go b/entity/entity.go
index 8d308b3..f91d02c 100755
--- a/entity/entity.go
+++ b/entity/entity.go
@@ -16,22 +16,14 @@ const (
 type EntityHandle uint64
 
 type Entity struct {
-
 	// Byte 1: Generation; Byte 2: Flags; Bytes 3-8: Index
-	ID    EntityHandle
-	Comps []Comp
+	ID EntityHandle
 }
 
 func (e *Entity) HasFlag(ef EntityFlag) bool {
 	return GetFlags(e.ID)&ef > 0
 }
 
-func (e *Entity) UpdateAllComps() {
-	for i := 0; i < len(e.Comps); i++ {
-		e.Comps[i].Update()
-	}
-}
-
 func GetGeneration(id EntityHandle) byte {
 	return byte(id >> GenerationShiftBits)
 }
diff --git a/entity/registry.go b/entity/registry.go
index 18be42f..bcefaa9 100755
--- a/entity/registry.go
+++ b/entity/registry.go
@@ -76,7 +76,7 @@ func (r *Registry) GetEntity(id EntityHandle) *Entity {
 	return e
 }
 
-// FreeEntity calls Destroy on all the entities components, resets the component list, resets the entity flags, then ads this entity to the free list
+// FreeEntity resets the entity flags then adds this entity to the free list
 func (r *Registry) FreeEntity(id EntityHandle) {
 
 	e := r.GetEntity(id)
@@ -84,14 +84,9 @@ func (r *Registry) FreeEntity(id EntityHandle) {
 		return
 	}
 
-	for i := 0; i < len(e.Comps); i++ {
-		e.Comps[i].Destroy()
-	}
-
 	r.EntityCount--
 	eIndex := GetIndex(e.ID)
 
-	e.Comps = []Comp{}
 	e.ID = NewEntityId(GetGeneration(e.ID), EntityFlag_None, eIndex)
 
 	r.FreeList = &freeListitem{
diff --git a/main.go b/main.go
index dc564e3..93b9189 100755
--- a/main.go
+++ b/main.go
@@ -89,16 +89,17 @@ func Test() {
 
 	lvl := level.NewLevel("test level", 1000)
 	e1 := lvl.Registry.NewEntity()
+	e1CompContainer := entity.NewCompContainer()
 
-	trComp := entity.GetComp[*TransformComp](e1)
+	trComp := entity.GetComp[*TransformComp](&e1CompContainer)
 	fmt.Println("Get comp before adding any:", trComp)
 
-	entity.AddComp(e1, &TransformComp{
+	entity.AddComp(e1, &e1CompContainer, &TransformComp{
 		Pos:   gglm.NewVec3(0, 0, 0),
 		Rot:   gglm.NewQuatEulerXYZ(0, 0, 0),
 		Scale: gglm.NewVec3(0, 0, 0),
 	})
-	trComp = entity.GetComp[*TransformComp](e1)
+	trComp = entity.GetComp[*TransformComp](&e1CompContainer)
 	fmt.Println("Get transform comp:", trComp)
 
 	fmt.Printf("Entity: %+v\n", e1)