tinyecs/
entity.rs

1use std::collections::HashMap;
2use std::ops::{Deref, DerefMut, Drop};
3use std::any::{Any, TypeId};
4
5use std::cell::RefCell;
6use component::*;
7
8pub struct Entity {
9    pub id                 : i32,
10    pub components         : RefCell<HashMap<TypeId, Box<Any>>>,
11    pub fresh              : RefCell<bool>
12}
13
14pub struct ComponentGuard<'a, T : Any> {
15    component  : Option<Box<T>>,
16    collection : &'a RefCell<HashMap<TypeId, Box<Any>>>
17}
18impl <'a, T : Any> Deref for ComponentGuard<'a, T> {
19    type Target = T;
20    fn deref(&self) -> &T {
21        self.component.as_ref().unwrap()
22    }
23}
24
25impl <'a, T : Any> DerefMut for ComponentGuard<'a, T> {
26    fn deref_mut(&mut self) -> &mut T {
27        self.component.as_mut().unwrap()
28    }
29}
30impl<'a, T : Any> Drop for ComponentGuard<'a, T> {
31    fn drop(&mut self) {
32        self.component.take().and_then(|component| {
33            self.collection.borrow_mut().insert(TypeId::of::<T>(), component)
34        });
35    }
36}
37
38impl Entity {
39    pub fn new(id : i32) -> Entity {
40        Entity {
41            id                 : id,
42            components         : RefCell::new(HashMap::new()),
43            fresh              : RefCell::new(false)
44        }
45    }
46
47    /// Mark this entity as not refreshed.
48    /// On beginning of next frame new registered components will affect their systems.
49    pub fn refresh(&self) {
50        *self.fresh.borrow_mut() = false;
51    }
52    pub fn add_component<T : Any + Component>(&self, component : T) {
53        self.components.borrow_mut().insert(TypeId::of::<T>(), Box::new(component));
54    }
55
56    /// Remove component of given type from entity
57    /// Be carefull, if this component is borrowed at this moment, it will not be really deleted.
58    pub fn remove_component<T : Any>(&self) {
59        self.components.borrow_mut().remove(&TypeId::of::<T>());
60    }
61
62    pub fn has_component<T : Any>(&self) -> bool {
63        self.components.borrow().contains_key(&TypeId::of::<T>())
64    }
65
66    /// Move component from entity to CompoentGuard. In general case, it behaves like &mut T.
67    /// While component is borrowed, second get_component() with same type will cause panic
68    pub fn get_component<T : Any + Component>(&self) -> ComponentGuard<T> {
69        let component = self.components.borrow_mut().remove(&TypeId::of::<T>()).unwrap();
70        let c : Box<T> = component.downcast().unwrap();
71
72        ComponentGuard {
73            component: Some(c),
74            collection: &self.components,
75        }
76    }
77
78    #[doc(hidden)]
79    pub fn get_components<T : Any + Component, T1 : Any + Component>(&self) -> (ComponentGuard<T>, ComponentGuard<T1>) {
80        (self.get_component::<T>(), self.get_component::<T1>())
81    }
82    #[doc(hidden)]
83    pub fn get_components3<T : Any + Component, T1 : Any + Component, T2 : Any + Component>(&self) -> (ComponentGuard<T>, ComponentGuard<T1>, ComponentGuard<T2>) {
84        (self.get_component::<T>(), self.get_component::<T1>(), self.get_component::<T2>())
85    }
86}
87
88#[test]
89fn get_component_test() {
90    use world::World;
91    struct Position {x : i32};
92    impl Component for Position{}
93    let mut world = World::new();
94    let eid = {
95        let mut entity_manager = world.entity_manager();
96        let entity = entity_manager.create_entity();
97        {
98            entity.add_component(Position {x : 2});
99            entity.refresh();
100        }
101        entity.id
102    };
103    world.update();
104    {
105        let mut entity_manager = world.entity_manager();
106        let entity = entity_manager.try_get_entity(eid).unwrap();
107        let mut some = entity.get_component::<Position>();
108        entity.refresh();
109        some.x += 1;
110    }
111    {
112        let mut entity_manager = world.entity_manager();
113        let entity = entity_manager.try_get_entity(eid).unwrap();
114
115        entity.remove_component::<Position>();
116        entity.refresh();
117    }
118    world.update();
119    {
120        let mut entity_manager = world.entity_manager();
121        let entity = entity_manager.try_get_entity(eid).unwrap();
122        assert_eq!(entity.has_component::<Position>(), false);
123    }
124
125}
tinyecs/entity.rs

tinyecs/
entity.rs
