Started moving SFML specific stuff into the sfml/ directory.

sfml/textures.hpp

@@ -0,0 +1,27 @@
+#pragma once
+#include <cstdint>
+#include <vector>
+#include <string>
+#include <SFML/Graphics.hpp>
+#include <unordered_map>
+#include <memory>
+
+namespace textures {
+
+  struct SpriteTexture {
+    std::shared_ptr<sf::Sprite> sprite = nullptr;
+    std::shared_ptr<sf::Texture> texture = nullptr;
+  };
+
+  struct TextureManager {
+    std::vector<sf::Image> surfaces;
+    std::unordered_map<std::string, SpriteTexture> sprite_textures;
+    std::unordered_map<wchar_t, int> char_to_texture;
+  };
+
+  void init();
+
+  SpriteTexture get(const std::string& name);
+
+  sf::Image load_image(const std::string& filename);
+}