staging some future refactoring, .h -> hpp, fix for rendering w/ audio

src/resource/audio.hpp

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <SDL3_mixer/SDL_mixer.h>
+#include <cstddef>
+#include <filesystem>
+#include <vector>
+
+namespace anm2ed::resource
+{
+  class Audio
+  {
+    MIX_Audio* internal{nullptr};
+    MIX_Track* track{nullptr};
+    std::vector<unsigned char> data{};
+    MIX_Mixer* mixer_get();
+    void unload();
+
+  public:
+    Audio(const unsigned char*, size_t);
+    Audio(const std::filesystem::path&);
+    ~Audio();
+    Audio() = default;
+    Audio(const Audio&);
+    Audio(Audio&&) noexcept;
+    Audio& operator=(const Audio&);
+    Audio& operator=(Audio&&) noexcept;
+
+    bool is_valid();
+    void play(bool loop = false, MIX_Mixer* = nullptr);
+    void stop(MIX_Mixer* = nullptr);
+    bool is_playing() const;
+  };
+}