#pragma once

#ifndef OFFSCREENGL_H

#define OFFSCREENGL_H

#if defined(LINUX) || defined(FREEBSD) || 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(FREEBSD) || 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(FREEBSD) || 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(FREEBSD) || defined(MACOSX)

  TOfflineGL *m_offlineGL;

#endif

#endif

};

#endif