add entity library

src/objects/Entities.cpp

@@ -20,16 +20,16 @@ void Transform::refresh() {
 Entities::Entities(Level* level) : level(level) {
 }
 
-void Entities::drop(glm::vec3 pos, glm::vec3 vel) {
+entityid_t Entities::drop(glm::vec3 pos) {
     auto entity = registry.create();
     glm::vec3 size(1);
-    registry.emplace<EntityId>(entity, static_cast<entityid_t>(1));
+    auto id = nextID++;
+    registry.emplace<EntityId>(entity, static_cast<entityid_t>(id));
     registry.emplace<Transform>(entity, pos, size/4.0f, glm::mat3(1.0f));
     registry.emplace<Hitbox>(entity, pos, 
         glm::vec3(size.x*0.2f, size.y*0.5f, size.z*0.2f));
-
-    auto& hitbox = registry.get<Hitbox>(entity);
-    hitbox.velocity = vel;
+    entities[id] = entity;
+    return id;
 }
 
 void Entities::updatePhysics(float delta){

src/objects/Entities.hpp

@@ -2,7 +2,9 @@
 #define OBJECTS_ENTITIES_HPP_
 
 #include "../typedefs.hpp"
+#include "../physics/Hitbox.hpp"
 
+#include <optional>
 #include <glm/glm.hpp>
 #include <unordered_map>
 #include <entt/entity/registry.hpp>
@@ -28,9 +30,9 @@ class Rig;
 
 class Entity {
     entt::registry& registry;
-    entt::entity entity;
+    const entt::entity entity;
 public:
-    Entity(entt::registry& registry, entt::entity entity)
+    Entity(entt::registry& registry, const entt::entity entity)
     : registry(registry), entity(entity) {}
 
     bool isValid() const {
@@ -41,6 +43,10 @@ public:
         return registry.get<Transform>(entity);
     }
 
+    Hitbox& getHitbox() const {
+        return registry.get<Hitbox>(entity);
+    }
+
     entityid_t getUID() const {
         return registry.get<EntityId>(entity).uid;
     }
@@ -50,12 +56,21 @@ class Entities {
     entt::registry registry;
     Level* level;
     std::unordered_map<entityid_t, entt::entity> entities;
+    entityid_t nextID = 1;
 public:
     Entities(Level* level);
     void updatePhysics(float delta);
     void render(Assets* assets, ModelBatch& batch, Frustum& frustum);
 
-    void drop(glm::vec3 pos, glm::vec3 vel);
+    entityid_t drop(glm::vec3 pos);
+
+    std::optional<Entity> get(entityid_t id) {
+        const auto& found = entities.find(id);
+        if (found != entities.end()) {
+            return Entity(registry, found->second);
+        }
+        return std::nullopt;
+    }
 };
 
 #endif // OBJECTS_ENTITIES_HPP_