51 lines
1.4 KiB
Go
51 lines
1.4 KiB
Go
package observers
|
|
|
|
import (
|
|
"github.com/mlange-42/arche/ecs"
|
|
"github.com/mlange-42/arche/ecs/event"
|
|
"github.com/mlange-42/arche/generic"
|
|
"github.com/mlange-42/arche/listener"
|
|
)
|
|
|
|
// will be added as an ecs.Resource to the world so we can use it in
|
|
// CollisionSystem to dynamically make it appear or disappear
|
|
type EntityObserver struct {
|
|
// we only have one obstacle so far, if we use multiple ones, turn
|
|
// this in to a map, see player_observer.go for an example
|
|
Entities map[ecs.Entity]int
|
|
}
|
|
|
|
func NewEntityObserver(world *ecs.World) {
|
|
observer := &EntityObserver{}
|
|
observer.Entities = make(map[ecs.Entity]int)
|
|
|
|
resmanger := generic.NewResource[EntityObserver](world)
|
|
resmanger.Add(observer)
|
|
|
|
listen := listener.NewCallback(
|
|
func(world *ecs.World, event ecs.EntityEvent) {
|
|
observerID := ecs.ResourceID[EntityObserver](world)
|
|
observer := world.Resources().Get(observerID).(*EntityObserver)
|
|
observer.RemoveEntity(event.Entity)
|
|
},
|
|
|
|
event.EntityRemoved,
|
|
)
|
|
|
|
world.SetListener(&listen)
|
|
}
|
|
|
|
func GetEntityObserver(world *ecs.World) *EntityObserver {
|
|
observerID := ecs.ResourceID[EntityObserver](world)
|
|
observer := world.Resources().Get(observerID).(*EntityObserver)
|
|
return observer
|
|
}
|
|
|
|
func (observer *EntityObserver) AddEntity(entity ecs.Entity) {
|
|
observer.Entities[entity] = 1
|
|
}
|
|
|
|
func (observer *EntityObserver) RemoveEntity(entity ecs.Entity) {
|
|
observer.Entities = make(map[ecs.Entity]int)
|
|
}
|