class PPU : public Processor, public PPUcounter, public MMIO {
public:
  enum : bool { Threaded = true };
  enum : bool { SupportsLayerEnable = false };
  enum : bool { SupportsFrameSkip = false };

  alwaysinline void step(unsigned clocks);
  alwaysinline void synchronize_cpu();

  void latch_counters();
  bool interlace() const;
  bool overscan() const;
  bool hires() const;

  void enter();
  void power();
  void reset();

  void layer_enable(unsigned, unsigned, bool) {}
  void set_frameskip(unsigned) {}

  void serialize(serializer&);
  PPU();
  ~PPU();

private:
  uint16 *surface;
  uint16 *output;

  uint8 ppu1_version;
  uint8 ppu2_version;

  struct {
    bool interlace;
    bool overscan;
  } display;

  #include "background/background.hpp"
  #include "mmio/mmio.hpp"
  #include "screen/screen.hpp"
  #include "sprite/sprite.hpp"
  #include "window/window.hpp"

  Background bg1;
  Background bg2;
  Background bg3;
  Background bg4;
  Sprite oam;
  Window window;
  Screen screen;

  static void Enter();
  void add_clocks(unsigned);

  void scanline();
  void frame();

  friend class PPU::Background;
  friend class PPU::Sprite;
  friend class PPU::Window;
  friend class PPU::Screen;
  friend class Video;
};

#if defined(DEBUGGER)
  #include "debugger/debugger.hpp"
  extern PPUDebugger ppu;
#else
  extern PPU ppu;
#endif