Add: [Win32] Video driver that uses OpenGL to transfer the video buffer to the screen.

src/video/win32_v.h

@@ -48,8 +48,10 @@ protected:
 
 	void Initialize();
 	bool MakeWindow(bool full_screen);
-	virtual uint8 GetFullscreenBpp();
+	void ClientSizeChanged(int w, int h);
 
+	/** Get screen depth to use for fullscreen mode. */
+	virtual uint8 GetFullscreenBpp();
 	/** (Re-)create the backing store. */
 	virtual bool AllocateBackingStore(int w, int h, bool force = false) = 0;
 	/** Palette of the window has changed. */
@@ -58,8 +60,6 @@ protected:
 private:
 	std::unique_lock<std::recursive_mutex> draw_lock;
 
-	void ClientSizeChanged(int w, int h);
-
 	static void PaintThreadThunk(VideoDriver_Win32Base *drv);
 
 	friend LRESULT CALLBACK WndProcGdi(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
@@ -102,4 +102,46 @@ public:
 	Driver *CreateInstance() const override { return new VideoDriver_Win32GDI(); }
 };
 
+#ifdef WITH_OPENGL
+
+/** The OpenGL video driver for windows. */
+class VideoDriver_Win32OpenGL : public VideoDriver_Win32Base {
+public:
+	VideoDriver_Win32OpenGL() : dc(nullptr), gl_rc(nullptr) {}
+
+	const char *Start(const StringList &param) override;
+
+	void Stop() override;
+
+	bool ToggleFullscreen(bool fullscreen) override;
+
+	bool AfterBlitterChange() override;
+
+	const char *GetName() const override { return "win32-opengl"; }
+
+protected:
+	HDC   dc;          ///< Window device context.
+	HGLRC gl_rc;       ///< OpenGL context.
+
+	uint8 GetFullscreenBpp() override { return 32; } // OpenGL is always 32 bpp.
+
+	void Paint() override;
+	void PaintThread() override {}
+
+	bool AllocateBackingStore(int w, int h, bool force = false) override;
+	void PaletteChanged(HWND hWnd) override {}
+
+	const char *AllocateContext();
+	void DestroyContext();
+};
+
+/** The factory for Windows' OpenGL video driver. */
+class FVideoDriver_Win32OpenGL : public DriverFactoryBase {
+public:
+	FVideoDriver_Win32OpenGL() : DriverFactoryBase(Driver::DT_VIDEO, 9, "win32-opengl", "Win32 OpenGL Video Driver") {}
+	/* virtual */ Driver *CreateInstance() const override { return new VideoDriver_Win32OpenGL(); }
+};
+
+#endif /* WITH_OPENGL */
+
 #endif /* VIDEO_WIN32_H */