OpenSceneGraph/src/osgViewer/Win32GWUtils

#ifndef _OSGVIEWER_WIN32GWUtils_H_
#define _OSGVIEWER_WIN32GWUtils_H_

#if defined(OSG_USE_EGL)
#include <EGL/egl.h>
#define EGL_EGLEXT_PROTOTYPES
#include <EGL/eglext.h>
#endif

#include <osg/GraphicsContext>

namespace osgViewer {
		
	template <typename T> class XGLAttributes
	{
	public:

		XGLAttributes() {}
		~XGLAttributes() {}

		void begin() { m_parameters.clear(); }
		void set(const T& id, const T& value) { add(id); add(value); }
		void enable(const T& id) { add(id); add(true); }
		void disable(const T& id) { add(id); add(false); }
		#if defined(OSG_USE_EGL)
		void end() { add(EGL_NONE); }
		#else
		void end() { add(0); }
		#endif

		const T* get() const { return &m_parameters.front(); }

	protected:

		void add(const T& t) { m_parameters.push_back(t); }

		std::vector<T>    m_parameters;        // parameters added

	private:

		// No implementation for these
		XGLAttributes(const XGLAttributes&);
		XGLAttributes& operator=(const XGLAttributes&);
	};
	
	typedef XGLAttributes<int>   XGLIntegerAttributes;
	typedef XGLAttributes<float> XGLFloatAttributes;

	void reportError(const std::string& msg);
	void reportError(const std::string& msg, unsigned int errorCode);
	void reportErrorForScreen(const std::string& msg, const osg::GraphicsContext::ScreenIdentifier& si, unsigned int errorCode);


	#if defined(OSG_USE_EGL)
	namespace EGL {
		struct ContextInfo {
			ContextInfo();
			ContextInfo(EGLContext _eglContext, EGLDisplay _eglDisplay, EGLSurface _eglSurface);
			ContextInfo(const ContextInfo& o);
			ContextInfo& operator=(const ContextInfo& o);
			void clear();
			bool isEmpty();
			EGLContext  eglContext;
			EGLDisplay  eglDisplay;
			EGLSurface  eglSurface;
		};

		// A class representing an OpenGL rendering context 
		class OpenGLContext
		{
		public:

			OpenGLContext();
			OpenGLContext(HWND hwnd, HDC hdc, EGLContext eglContext, EGLDisplay eglDisplay, EGLSurface eglSurface);

			~OpenGLContext();

			void set(HWND hwnd, HDC hdc, EGLContext eglContext, EGLDisplay eglDisplay, EGLSurface eglSurface, EGLConfig eglConfig);
			void clear();

			HDC deviceContext();
			EGLConfig getConfig();

			bool makeCurrent(HDC restoreOnHdc, bool restorePreviousOnExit);
			ContextInfo& contextInfo();

		protected:

			EGL::ContextInfo _eglCtx;
			EGLConfig _eglConfig;

			HDC   _previousHdc;             // previously HDC to restore rendering context on
			EGLContext _previousContext;           // previously current rendering context

			HWND  _hwnd;                    // handle to OpenGL window
			HDC   _hdc;                     // handle to device context

		private:

			// no implementation for these
			OpenGLContext(const OpenGLContext&);
			OpenGLContext& operator=(const OpenGLContext&);
		};

		bool createDisplaySurfaceAndContext(ContextInfo& context, EGLConfig& config, XGLAttributes<int>& configAttribs, HWND hwnd, HDC hdc);
		bool createDisplaySurfaceAndContextForPBuffer(ContextInfo& context, EGLConfig& config, XGLAttributes<int>& configAttribs);
		EGLContext createContext(EGLDisplay eglDisplay, const EGLConfig& config);
		void destroyContext(ContextInfo& c);
		void preparePixelFormatSpecifications(const osg::GraphicsContext::Traits& traits, XGLIntegerAttributes& attributes, bool allowSwapExchangeARB);
	} // end of namespace EGL

	#else

	namespace WGL {
		class OpenGLContext
		{
		public:

			OpenGLContext();
			OpenGLContext(HWND hwnd, HDC hdc, HGLRC hglrc);

			~OpenGLContext();

			void set(HWND hwnd, HDC hdc, HGLRC hglrc);

			void clear();

			HDC deviceContext();

			bool makeCurrent(HDC restoreOnHdc, bool restorePreviousOnExit);

		protected:

			//
			// Data members
			//

			HDC   _previousHdc;             // previously HDC to restore rendering context on
			HGLRC _previousHglrc;           // previously current rendering context
			HWND  _hwnd;                    // handle to OpenGL window
			HDC   _hdc;                     // handle to device context
			HGLRC _hglrc;                   // handle to OpenGL rendering context
			bool  _restorePreviousOnExit;   // restore original context on exit

		private:

			// no implementation for these
			OpenGLContext(const OpenGLContext&);
			OpenGLContext& operator=(const OpenGLContext&);
		};
	} // end of namespace WGL
	#endif

}

#endif