#ifndef OFFSCREENGL_H
#define OFFSCREENGL_H
#if defined(LINUX) || defined(MACOSX)
#include "tofflinegl.h"
#endif

class OffScreenGL
{
public:
	OffScreenGL(int width, int height, int bpp, int stencilBpp = 0)
	{
// ----------------------------------------------------------------------------------- //
// creo il contesto openGL                                                             //
// ----------------------------------------------------------------------------------- //
#ifdef WIN32
		initBITMAPINFO(m_info, width, height, bpp);

		m_offData = 0; // a pointer to buffer
		m_offHdc =	 // open an offscreen device
			GetDC(NULL);

		m_offDIB = // and a bitmap image
			CreateDIBSection(m_offHdc, &m_info, DIB_RGB_COLORS, &m_offData, NULL, 0);

		assert(m_offDIB);
		assert(m_offData);

		m_offDC = CreateCompatibleDC(m_offHdc);

		m_oldobj = // select BIB to write
			SelectObject(m_offDC, m_offDIB);

		static PIXELFORMATDESCRIPTOR pfd =
			{
				sizeof(PIXELFORMATDESCRIPTOR),													 // size of this pfd
				1,																				 // version number
				0 | (false ? (0) : (PFD_DRAW_TO_BITMAP | PFD_SUPPORT_GDI)) | PFD_SUPPORT_OPENGL, // support OpenGL
				PFD_TYPE_RGBA,																	 // RGBA type
				bpp,																			 // 32-bit color depth
				0, 0, 0, 0, 0, 0,																 // color bits ignored
				bpp >> 2,																		 // alpha buffer
				0,																				 // shift bit ignored
				0,																				 // no accumulation buffer
				0, 0, 0, 0,																		 // accum bits ignored
				0,																				 // 32-bit z-buffer
				stencilBpp,																		 // no stencil buffer
				0,																				 // no auxiliary buffer
				PFD_MAIN_PLANE,																	 // main layer
				0,																				 // reserved
				0, 0, 0																			 // layer masks ignored
			};
		//std::cout << "bit depth = " << v << std::endl;
		// get the best available match of pixel format for the device context
		int iPixelFormat = ChoosePixelFormat(m_offDC, &pfd);
		assert(iPixelFormat != 0);

		// make that the pixel format of the device context
		int ret = SetPixelFormat(m_offDC, iPixelFormat, &pfd);
		DWORD dw = GetLastError();
		assert(ret == TRUE);

		// make a valid context for OpenGL rendering
		m_hglRC = wglCreateContext(m_offDC);
		assert(m_hglRC);
/*
	  ret = wglMakeCurrent( m_offDC, m_hglRC );
	  assert(ret == TRUE);
    */
#else
#if defined(LINUX) || defined(MACOSX)
		m_offlineGL = new TOfflineGL(TDimension(width, height));
#endif
#endif
	}

	~OffScreenGL()
	{
// ----------------------------------------------------------------------------------- //
// cancello il contesto openGL                                                         //
// ----------------------------------------------------------------------------------- //
#ifdef WIN32
		wglDeleteContext(m_hglRC);

		// release object
		SelectObject(m_offDC, m_oldobj);

		DeleteObject(m_offDC);
		DeleteObject(m_offDIB);
		DeleteObject(m_offHdc);
#else
#if defined(LINUX) || defined(MACOSX)

		delete m_offlineGL;
#endif
#endif
	}

public:
// init a BITMAPINFO structure
#ifdef WIN32
	void initBITMAPINFO(BITMAPINFO &info, int width, int height, int bpp)
	{
		memset(&info, 0, sizeof(BITMAPINFOHEADER));

		info.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
		info.bmiHeader.biWidth = width;
		info.bmiHeader.biHeight = height;
		info.bmiHeader.biPlanes = 1;
		info.bmiHeader.biBitCount = bpp;
		info.bmiHeader.biCompression = BI_RGB;
		info.bmiHeader.biSizeImage = 0;
		info.bmiHeader.biXPelsPerMeter = 1000;
		info.bmiHeader.biYPelsPerMeter = 1000;
		info.bmiHeader.biClrUsed = 0;
		info.bmiHeader.biClrImportant = 0;
	}

	void *m_offData;
	HDC m_offHdc;
	HBITMAP m_offDIB;
	HDC m_offDC;
	HGDIOBJ m_oldobj;
	HGLRC m_hglRC;
	BITMAPINFO m_info;
#else
#if defined(LINUX) || defined(MACOSX)
	TOfflineGL *m_offlineGL;
#endif
#endif
};

#endif