feat: Generalizing resource handling

SFMLEngine/makingAGameTick/game.cpp

@@ -26,13 +26,13 @@ class Game
     bool mIsMovingDown = false;
   private:
     sf::RenderWindow mWindow;
-    TextureHolder mTexture;
+    ResourceHolder<sf::Texture, Textures::ID> mTexture;
     sf::Sprite mPlayer;
 };
 
 Game::Game() : mWindow(sf::VideoMode(640, 480), "SFML Application"), mTexture(), mPlayer()
 {
-  //TextureHolder textures;
+  //ResourceHolder textures;
   mTexture.load(Textures::Airplane, PATH_TO_PLAYER_TEXTURE);
 
   mPlayer.setTexture(mTexture.get(Textures::Airplane));

SFMLEngine/makingAGameTick/resources.hpp

@@ -9,14 +9,15 @@ namespace Textures // This gives us a scope for the enumerators which allows us
   enum ID { Landscape, Airplane, Missile };
 }
 
-class TextureHolder
+template <typename Resource, typename Identifier>
+class ResourceHolder
 {
   public:
-    void load(Textures::ID id, const std::string& filename);
-    sf::Texture& get(Textures::ID id);
-    const sf::Texture& get(Textures::ID id) const;
+    void load(Identifier id, const std::string& filename);
+    Resource& get(Identifier id);
+    const Resource& get(Identifier id) const;
   private:
-    std::map< Textures::ID, std::unique_ptr<sf::Texture> > mTextureMap;
+    std::map< Identifier, std::unique_ptr<Resource> > mResourceMap;
     // unique_ptr are class templates that act like pointers, this allows us to work with heavyweight objects without copying them all the time, or we can store classes that are non-cpyable like sf::Shader
 };
 

SFMLEngine/makingAGameTick/resources.inl

@@ -1,29 +1,31 @@
 #ifndef RESOURCES_INL
 #define RESOURCES_INL
 
-
-void TextureHolder::load(Textures::ID id, const std::string& filename)
+template <typename Resource, typename Identifier>
+void ResourceHolder<Resource, Identifier>::load(Identifier id, const std::string& filename)
 // Function to load a resource, it takes one parameter for filename and one for identifier
 {
-  std::unique_ptr<sf::Texture> texture(new sf::Texture()); // Create sf:Texture and store it in the unique pointer
+  std::unique_ptr<Resource> texture(new Resource()); // Create sf:Texture and store it in the unique pointer
   if(!texture -> loadFromFile(filename))// Load the texture from the filename
   {
     throw std::runtime_error(TEXTURE_LOAD_ERROR + filename);
   }
-  auto inserted = mTextureMap.insert(std::make_pair(id, std::move(texture))); // Insert texture into map mTextureMap, std::move used to take ownership from texture variable and transfer it to std::make_pair(), std::move moves the resource into a new place and removes it from earlier place https://en.cppreference.com/w/cpp/utility/move
+  auto inserted = mResourceMap.insert(std::make_pair(id, std::move(texture))); // Insert texture into map mResourceMap, std::move used to take ownership from texture variable and transfer it to std::make_pair(), std::move moves the resource into a new place and removes it from earlier place https://en.cppreference.com/w/cpp/utility/move
   assert(inserted.second);
 }
 
-sf::Texture& TextureHolder::get(Textures::ID id) // returns a reference to a texture
+template <typename Resource, typename Identifier>
+Resource& ResourceHolder<Resource, Identifier>::get(Identifier id) // returns a reference to a texture
 {
-  auto found = mTextureMap.find(id); // find returns an iterator to the found element or end() if nothing was found
-  assert(found != mTextureMap.end());
+  auto found = mResourceMap.find(id); // find returns an iterator to the found element or end() if nothing was found
+  assert(found != mResourceMap.end());
   return *found -> second; // We have to access the second member of the pointer, then we deference it and get a texture
 }
 
-const sf::Texture& TextureHolder::get(Textures::ID id) const // we need to be able to invoke get() also if we only have a pointer/reference to the const TextureHolder, it returns const sf::Texture so the texture cannot be changed by caller
+template <typename Resource, typename Identifier>
+const Resource& ResourceHolder<Resource, Identifier>::get(Identifier id) const // we need to be able to invoke get() also if we only have a pointer/reference to the const ResourceHolder<Resource, Identifier>, it returns const Resource so the texture cannot be changed by caller
 {
-  auto found = mTextureMap.find(id); // find returns an iterator to the found element or end() if nothing was found
+  auto found = mResourceMap.find(id); // find returns an iterator to the found element or end() if nothing was found
   return *found -> second; // We have to access the second member of the pointer, then we deference it and get a texture
 }