//----------------------------------------------------------------------------
//  EgalTech 2020-2022
//----------------------------------------------------------------------------
// File : IntersLineBox.cpp       Data : 08.01.22         Versione : 2.4a3
// Contenuto : Implementazione della intersezione linea/box.
//
//
//
// Modifiche : 07.05.20 DS Creazione modulo.
//
//
//----------------------------------------------------------------------------

//--------------------------- Include ----------------------------------------
#include "stdafx.h"
#include "IntersLineBox.h"
#include "/EgtDev/Include/EGkIntersLineBox.h"
#include "/EgtDev/Include/EgtNumUtils.h"
#include <algorithm>

using namespace std ;

//----------------------------------------------------------------------------
// Linea e box allineato assi devono essere nel medesimo sistema di riferimento.
// In caso di intersezione viene restituito true e i parametri lunghezza in dU1 e dU2.
//----------------------------------------------------------------------------
bool
IntersLineBox( const Point3d& ptL, const Vector3d& vtL,
               const Point3d& ptMin, const Point3d& ptMax,
               double& dU1, double& dU2)
{
  // Verifico il versore
   if ( vtL.IsSmall())
      return false ;

  // Verifico gli estremi del box
   if ( ptMin.x > ptMax.x + EPS_SMALL  ||
        ptMin.y > ptMax.y + EPS_SMALL  ||
        ptMin.z > ptMax.z + EPS_SMALL)
      return false ;

  // Casi di intersezione impossibile
   if ( abs( vtL.x) < EPS_ZERO  &&  ( ptL.x < ptMin.x - EPS_SMALL  ||  ptL.x > ptMax.x + EPS_SMALL))
      return false ;
   if ( abs( vtL.y) < EPS_ZERO  &&  ( ptL.y < ptMin.y - EPS_SMALL  ||  ptL.y > ptMax.y + EPS_SMALL))
      return false ;
   if ( abs( vtL.z) < EPS_ZERO  &&  ( ptL.z < ptMin.z - EPS_SMALL  ||  ptL.z > ptMax.z + EPS_SMALL))
      return false ;

  // Parametri degli estremi della retta
   dU1 = -INFINITO ;
   dU2 = INFINITO ;

  // Confronto con piani YZ (perpendicolari ad asse X)
   if ( vtL.x > EPS_ZERO) {
      dU1 = max( dU1, ( ptMin.x - ptL.x) / vtL.x) ;
      dU2 = min( dU2, ( ptMax.x - ptL.x) / vtL.x) ;
   }
   else if ( vtL.x < -EPS_ZERO) {
      dU1 = max( dU1, ( ptMax.x - ptL.x) / vtL.x) ;
      dU2 = min( dU2, ( ptMin.x - ptL.x) / vtL.x) ;
   }

  // Confronto con piani ZX (perpendicolari ad asse Y)
   if ( vtL.y > EPS_ZERO) {
      dU1 = max( dU1, ( ptMin.y - ptL.y) / vtL.y) ;
      dU2 = min( dU2, ( ptMax.y - ptL.y) / vtL.y) ;
   }
   else if ( vtL.y < -EPS_ZERO) {
      dU1 = max( dU1, ( ptMax.y - ptL.y) / vtL.y) ;
      dU2 = min( dU2, ( ptMin.y - ptL.y) / vtL.y) ;
   }

  // Confronto con piani XY (perpendicolari ad asse Z)
   if ( vtL.z > EPS_ZERO) {
      dU1 = max( dU1, ( ptMin.z - ptL.z) / vtL.z) ;
      dU2 = min( dU2, ( ptMax.z - ptL.z) / vtL.z) ;
   }
   else if ( vtL.z < -EPS_ZERO){
      dU1 = max( dU1, ( ptMax.z - ptL.z) / vtL.z) ;
      dU2 = min( dU2, ( ptMin.z - ptL.z) / vtL.z) ;
   }

   return ( dU2 >= dU1) ;
}

//----------------------------------------------------------------------------
bool
IntersLineBox( const Point3d& ptL1, const Point3d& ptL2, const BBox3d& b3Box, INTDBLVECTOR& vInters, bool bFinite)
{
   Vector3d vtL = ptL2 - ptL1 ;
   double dLen = vtL.Len() ;
   if ( dLen > EPS_SMALL) 
      vtL /= dLen ;
   else
      vtL = V_NULL ;
   return IntersLineBox( ptL1, vtL, dLen, b3Box, vInters, bFinite) ;
}

//----------------------------------------------------------------------------
bool
IntersLineBox( const Point3d& ptL, const Vector3d& vtL, double dLen, const BBox3d& b3Box, INTDBLVECTOR& vInters, bool bFinite)
{
  // Recupero i dati del Box
   Point3d ptMin, ptMax ;
   if ( ! b3Box.GetMinMax( ptMin, ptMax))
      return false ;

  // Pulisco vettore intersezioni
   vInters.clear() ;

  // Eseguo intersezione della linea completa
   double dU1, dU2 ;
   bool bInters = IntersLineBox( ptL, vtL, b3Box.GetMin(), b3Box.GetMax(), dU1, dU2) ;

  // Se non c'è intersezione
   if ( ! bInters  ||  ( bFinite  &&  ( dU1 > dLen + EPS_SMALL  ||  dU2 < -EPS_SMALL)))
      return true ;

  // Se le due intersezioni coincidono
   if ( ( dU2 - dU1) < EPS_SMALL) {
      double dU = ( dU1 + dU2) / 2 ;
      if ( ! bFinite) {
         vInters.emplace_back( ILBT_TOUCH, dU) ;
      }
      else {
         if ( dU > - EPS_SMALL  &&  dU < dLen + EPS_SMALL)
            vInters.emplace_back( ILBT_TOUCH, Clamp( dU, 0., dLen)) ;
      }
      return true ;
   }

  // Se sono due intersezioni con la linea giacente su una faccia del box
   if ( ( abs( vtL.x) < EPS_ZERO  &&  ( abs( ptL.x - ptMin.x) < EPS_SMALL  ||  abs( ptL.x - ptMax.x) < EPS_SMALL))  ||
        ( abs( vtL.y) < EPS_ZERO  &&  ( abs( ptL.y - ptMin.y) < EPS_SMALL  ||  abs( ptL.y - ptMax.y) < EPS_SMALL))  ||
        ( abs( vtL.z) < EPS_ZERO  &&  ( abs( ptL.z - ptMin.z) < EPS_SMALL  ||  abs( ptL.z - ptMax.z) < EPS_SMALL))) {
      if ( ! bFinite) {
         vInters.emplace_back( ILBT_TG_INI, dU1) ;
         vInters.emplace_back( ILBT_TG_FIN, dU2) ;
      }
      else {
         if ( dU1 > dLen - EPS_SMALL)
            vInters.emplace_back( ILBT_IN, dLen) ;
         else if ( dU2 < EPS_SMALL)
            vInters.emplace_back( ILBT_OUT, 0) ;
         else {
            if ( dU1 < - EPS_SMALL)
               vInters.emplace_back( ILBT_TG_INSIDE, 0.) ;
            else
               vInters.emplace_back( ILBT_TG_INI, Clamp( dU1, 0., dLen)) ;
            if ( dU2 > dLen + EPS_SMALL)
               vInters.emplace_back( ILBT_TG_INSIDE, dLen) ;
            else
               vInters.emplace_back( ILBT_TG_FIN, Clamp( dU2, 0., dLen)) ;
         }
      }
      return true ;
   }

  // Altrimenti sono due intersezioni con attraversamento
   if ( ! bFinite) {
      vInters.emplace_back( ILBT_IN, dU1) ;
      vInters.emplace_back( ILBT_OUT, dU2) ;
   }
   else {
      if ( dU1 > dLen - EPS_SMALL)
         vInters.emplace_back( ILBT_IN, dLen) ;
      else if ( dU2 < EPS_SMALL)
         vInters.emplace_back( ILBT_OUT, 0) ;
      else {
         if ( dU1 < - EPS_SMALL)
            vInters.emplace_back( ILBT_INSIDE, 0.) ;
         else
            vInters.emplace_back( ILBT_IN, Clamp( dU1, 0., dLen)) ;
         if ( dU2 > dLen + EPS_SMALL)
            vInters.emplace_back( ILBT_INSIDE, dLen) ;
         else
            vInters.emplace_back( ILBT_OUT, Clamp( dU2, 0., dLen)) ;
      }
   }
   return true ;
}