//----------------------------------------------------------------------------
//  EgalTech 2017-2017
//----------------------------------------------------------------------------
// File : SceneImage.cpp         Data : 11.02.17           Versione : 1.8b2
// Contenuto : Implementazione della gestione immagini della classe scena.
//
//
//
// Modifiche : 11.02.17 DS Creazione modulo.
//
//
//----------------------------------------------------------------------------

//--------------------------- Include ----------------------------------------
#include "stdafx.h"
#include "Scene.h"
#include "\EgtDev\Include\EgtStringConverter.h"
#include "\EgtDev\Extern\FreeImage\Include\FreeImage.h"

using namespace std ;

//----------------------------------------------------------------------------
bool
Scene::GetImage( int nShowMode, Color colBackTop, Color colBackBottom,
                 int nDestWidth, int nDestHeight, const string& sFile)
{
  // Cerco e verifico il formato del file da scrivere a partire dall'estensione
   FREE_IMAGE_FORMAT fif = FreeImage_GetFIFFromFilenameU( stringtoW( sFile)) ;
   if ( fif == FIF_UNKNOWN  ||  ! FreeImage_FIFSupportsWriting( fif))
      return false ;

  // Dimensioni della vista
   int nWidth = m_nViewportW ;
   int nHeight = m_nViewportH ;
   if ( nWidth == 0  ||  nHeight == 0)
      return false ;

  // Coefficienti di scalatura
   if ( nDestWidth == 0  ||  nDestHeight == 0)
      return false ;
   double dCoeffW = double( nDestWidth) / nWidth ;
   double dCoeffH = double( nDestHeight) / nHeight ;

  // Costanti per mask colori (BGRA)
   const unsigned int BLUE_MASK =  0xFF000000 ;
   const unsigned int GREEN_MASK = 0x00FF0000 ;
   const unsigned int RED_MASK =   0x0000FF00 ;

  // Alloco immagine complessiva
   int nN = max( int( dCoeffW + 0.5), 1) ;
   int nM = max( int( dCoeffH + 0.5), 1) ;
   FIBITMAP* pDib = FreeImage_Allocate( nN * nWidth, nM * nHeight, 32, RED_MASK, GREEN_MASK, BLUE_MASK) ;
   if ( pDib == nullptr)
      return false ;

  // Alloco il buffer di lettura dei pixel della vista OpenGL ( fattore 4 perché BGRA)
   BYTE* pBuffer = new BYTE[ 4 * nWidth * nHeight] ;
   if ( pBuffer == nullptr)
      return false ;

  // Salvo stato di visualizzazione
   int nCurrShowMode = m_nShowMode ;
   bool bCurrShowGrid = m_bShowGrid ;
   bool bCurrShowFrame = m_bShowFrame ;
   bool bCurrShowGlobFrame = m_bShowGlobFrame ;
   Color colCurrBackTop = m_colBackTop ;
   Color colCurrBackBottom = m_colBackBottom ;
  // Imposto attributi di visualizzazione
   m_nShowMode = nShowMode ;
   m_bShowGrid = false ;
   m_bShowFrame = false ;
   m_bShowGlobFrame = false ;
   m_colBackTop = colBackTop ;
   m_colBackBottom = colBackBottom ;
  // Salvo stato di zoom
   Point3d ptCurrCenter = m_ptCenter ;
   double dCurrHalfWidth = m_dHalfWidth ;
   double dCurrHalfHeight = m_dHalfHeight ;
  // Imposto zoom globale
   double dZoom = max( dCoeffW / nN, dCoeffH / nM) / min( dCoeffW / nN, dCoeffH / nM) ;
   m_dHalfWidth *= dZoom ;
   m_dHalfHeight *= dZoom ;

  // Eseguo N x M disegni
   double dCoeff = max( 1.0 / nN, 1.0 / nM) ;
   double dWs = m_dHalfWidth * dCoeff ;
   double dHs = m_dHalfHeight * dCoeff ;
   Vector3d vtX = m_vtUp ^ m_vtDirCamera ;
   Vector3d vtY = m_vtUp ;
   Point3d ptOrig = m_ptCenter - vtX * dWs * nN - vtY * dHs * nM ;
   for ( int i = 0 ; i < nN ; ++ i) {
      for ( int j = 0 ; j < nM ; ++ j) {
        // Aggiusto scalature
         m_ptCenter = ptOrig + vtX * (( 2 * i + 1) * dWs) + vtY * (( 2 * j + 1) * dHs) ;
         m_dHalfWidth = dWs ;
         m_dHalfHeight = dHs ;
        // Eseguo disegno sul back buffer
         if ( ! MyDraw( false)) {
            delete [] pBuffer ;         
            return false ;
         }
        // Leggo l'immagine nel buffer
         glReadBuffer( GL_BACK) ;
         glReadPixels( 0, 0, nWidth, nHeight, GL_BGRA, GL_UNSIGNED_BYTE, pBuffer) ;
        // Converto al formato di FreeImage
         FIBITMAP* pTmpDib = FreeImage_ConvertFromRawBits( pBuffer, nWidth, nHeight, 4 * nWidth, 32,
                                                           RED_MASK, GREEN_MASK, BLUE_MASK, false) ;
        // Inserisco nell'immagine complessiva
         FreeImage_Paste( pDib, pTmpDib, i * nWidth, ( nM - 1 - j) * nHeight, 255) ;
         FreeImage_Unload( pTmpDib) ;
      }
   }

  // Ripristino attributi di visualizzazione originali
   m_nShowMode = nCurrShowMode ;
   m_bShowGrid = bCurrShowGrid ;
   m_bShowFrame = bCurrShowFrame ;
   m_bShowGlobFrame = bCurrShowGlobFrame ;
   m_colBackBottom = colCurrBackBottom ;
   m_colBackTop = colCurrBackTop ;
  // Ripristino zoom
   m_ptCenter = ptCurrCenter ;
   m_dHalfWidth = dCurrHalfWidth ;
   m_dHalfHeight = dCurrHalfHeight ;

  // converto l'immagine a 24 bit per pixel
   FIBITMAP* pTmpDib = pDib ;
   pDib = FreeImage_ConvertTo24Bits( pTmpDib) ;
   FreeImage_Unload( pTmpDib) ;

  // Se necessario, eseguo scalatura della bitmap
   if ( nDestWidth != nN * nWidth  ||  nDestHeight != nM * nHeight) {
      int nLeft ; int nTop ;
      int nRight ; int nBottom ;
      if ( dCoeffW / nN >= dCoeffH / nM) {
         nLeft = 0 ;
         nRight = nN * nWidth - 1 ;
         int nDeltaH = nM * nHeight - nN * int( nDestHeight / dCoeffW) ;
         nTop = nDeltaH / 2 ;
         nBottom = nM * nHeight - nTop - 1 ; 
      }
      else {
         nTop = 0 ;
         nBottom = nM * nHeight - 1 ; 
         int nDeltaW = nN * nWidth - nM * int( nDestWidth / dCoeffH) ;
         nLeft = nDeltaW / 2 ;
         nRight = nN * nWidth - nLeft - 1 ;
      }
      FIBITMAP* pTmp2Dib = pDib ;
      pDib = FreeImage_RescaleRect( pTmp2Dib, nDestWidth, nDestHeight, nLeft, nTop, nRight, nBottom, FILTER_CATMULLROM) ;
      FreeImage_Unload( pTmp2Dib) ;
   }

  // Salvataggio
   int nFlag = 0 ;
   bool bOk = ( FreeImage_SaveU( fif, pDib, stringtoW( sFile), nFlag) != FALSE) ;

  // Libero le risorse
   FreeImage_Unload( pDib) ;
   delete [] pBuffer ;

   return bOk ;
}