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

src/resource/audio_stream.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+#include <SDL3_mixer/SDL_mixer.h>
+#include <vector>
+
+namespace anm2ed
+{
+  class AudioStream
+  {
+    static void callback(void*, MIX_Mixer*, const SDL_AudioSpec*, float*, int);
+
+  public:
+    std::vector<float> stream{};
+    SDL_AudioSpec spec{};
+
+    AudioStream(MIX_Mixer*);
+    void capture_begin(MIX_Mixer*);
+    void capture_end(MIX_Mixer*);
+  };
+}