Add GetValue() function (#129)

* fix test

* add GetValue function

entry.go

@@ -53,8 +53,12 @@ func Set[T any](e *Entry, ctype component.IComponentType, component *T) {
 
 // SetValue sets the value of the component.
 func SetValue[T any](e *Entry, ctype component.IComponentType, value T) {
-	c := Get[T](e, ctype)
-	*c = value
+	*Get[T](e, ctype) = value
+}
+
+// GetValue gets the value of the component.
+func GetValue[T any](e *Entry, ctype component.IComponentType) T {
+	return *Get[T](e, ctype)
 }
 
 // Remove removes the component from the entry.

entry_test.go

@@ -0,0 +1,61 @@
+package donburi_test
+
+import (
+	"testing"
+
+	"github.com/yohamta/donburi"
+)
+
+func TestSetValue(t *testing.T) {
+	var (
+		transform = donburi.NewComponentType[transformData]()
+	)
+	world := donburi.NewWorld()
+	a := world.Create(transform)
+	entryA := world.Entry(a)
+
+	trData := transformData{
+		Position: vec2f{10, 20},
+	}
+	donburi.SetValue(entryA, transform, trData)
+	got := donburi.GetValue[transformData](entryA, transform)
+
+	if got != trData {
+		t.Errorf("got: %v, want: %v", got, trData)
+	}
+}
+
+func TestGetComponents(t *testing.T) {
+	var (
+		transform = donburi.NewComponentType[transformData]()
+		velocity  = donburi.NewComponentType[velocityData]()
+		tag       = donburi.NewTag().SetName("tag")
+	)
+
+	world := donburi.NewWorld()
+	a := world.Create(transform, velocity, tag)
+	entryA := world.Entry(a)
+
+	trData := transformData{
+		Position: vec2f{10, 20},
+	}
+	veData := velocityData{
+		Velocity: vec2f{30, 40},
+	}
+
+	donburi.SetValue(entryA, transform, trData)
+	donburi.SetValue(entryA, velocity, veData)
+
+	gots := donburi.GetComponents(entryA)
+	wants := []interface{}{trData, veData, struct{}{}}
+
+	if len(gots) != len(wants) {
+		t.Fatalf("got: %v, want: %v", gots, wants)
+	}
+
+	for i, got := range gots {
+		if got != wants[i] {
+			t.Errorf("got: %v, want: %v", got, wants[i])
+		}
+	}
+}

internal/storage/mock.go

@@ -50,3 +50,7 @@ func (m *MockComponentType[T]) setDefaultVal(ptr unsafe.Pointer) {
 func (m *MockComponentType[T]) Name() string {
 	return fmt.Sprintf("%s[%s]", reflect.TypeOf(m).Name(), m.typ.Name())
 }
+
+func (m *MockComponentType[T]) Typ() reflect.Type {
+	return m.typ
+}