added transformable and implemented it for Transform

src/transform.h

@@ -2,6 +2,7 @@
 #define _fencer_transform_h
 
 #include "vmath.h"
+#include "transformable.h"
 
 typedef struct Transform Transform;
 struct Transform {
@@ -45,4 +46,31 @@ Vector transform_point(Transform* self, Vector position) {
     return vaddf(vmulf(transform_direction(self, position), self->scale), self->position);
 }
 
+static
+Transform* transform_get_transform(Transform* self) {
+    return self;
+}
+
+static
+Vector* transform_get_position(Transform* self) {
+    return &self->position;
+}
+
+static
+Vector* transform_get_scale(Transform* self) {
+    return &self->scale;
+}
+
+static
+float* transform_get_rotation(Transform* self) {
+    return &self->rotation;
+}
+
+impl_Transformable_for(Transform,
+    transform_get_transform,
+    transform_get_position,
+    transform_get_scale,
+    transform_get_rotation
+);
+
 #endif // !_fencer_transform_h

src/transformable.h

@@ -0,0 +1,33 @@
+#ifndef _fencer_transformable_h
+#define _fencer_transformable_h
+
+#include "vmath.h"
+#include "typeclass_helpers.h"
+
+typedef struct {
+    struct Transform* (*const get_transform)(void* self);
+    Vector* (*const get_position)(void* self);
+    Vector* (*const get_scale)(void* self);
+    float* (*const get_rotation)(void* self);
+} ITransformable;
+
+typedef struct {
+    void* self;
+    ITransformable const* tc;
+} Transformable;
+
+#define impl_Transformable_for(T, get_transform_f, get_position_f, get_scale_f, get_rotation_f)\
+static inline Transformable T##_as_Transformable(T* x) {\
+    TC_FN_TYPECHECK(Transform*, get_transform_f, T* e);\
+    TC_FN_TYPECHECK(Vector*, get_position_f, T* e);\
+    TC_FN_TYPECHECK(float*, get_rotation_f, T* e);\
+    static ITransformable const tc = {\
+        .get_transform =    (Transform*(*const)(void*)) get_transform_f,\
+        .get_position =     (Vector*(*const)(void*))    get_position_f,\
+        .get_scale =        (Vector*(*const)(void*))    get_scale_f,\
+        .get_rotation =     (float*(*const)(void*))     get_rotation_f\
+    };\
+    return (Transformable){.tc = &tc, .self = x };\
+}
+
+#endif // !_fencer_transformable_h

src/typeclass_helpers.h

@@ -0,0 +1,7 @@
+#ifndef _fencer_typeclass_helpers_h
+#define _fencer_typeclass_helpers_h
+
+#define TC_FN_TYPECHECK(__Return, __Name, ...)\
+__Return (*const __Name##_)(__VA_ARGS__) = __Name; (void)__Name##_
+
+#endif // !_fencer_typeclass_helpers_h