#include "CastorShape/PrecompiledHeader.hpp"

#include "CastorShape/main/RenderEngine.hpp"

#pragma warning( push )
#pragma warning( disable:4996 )

using namespace Castor3D;
using namespace Castor;
using namespace CastorShape;

RenderEngine :: RenderEngine( String const & p_strFileName, SceneSPtr p_pScene)
	:	m_strFileName( p_strFileName)
	,	m_pScene( p_pScene)
{
}

RenderEngine :: ~RenderEngine()
{
}

bool RenderEngine :: Draw()
{
	bool l_bReturn = false;
	std::ofstream l_imageFile( str_utils::to_str( m_strFileName ), std::ios_base::binary );

	if (l_imageFile)
	{
		int l_iSizeX = 256;
		int l_iSizeY = 256;

		// Ajout du header TGA
		l_imageFile.put( 0).put( 0);
		l_imageFile.put( 2);        /* RGB non compresse */

		l_imageFile.put( 0).put( 0);
		l_imageFile.put( 0).put( 0);
		l_imageFile.put( 0);

		l_imageFile.put( 0).put( 0); /* origine X */
		l_imageFile.put( 0).put( 0); /* origine Y */

		l_imageFile.put( char( l_iSizeX & 0x00FF ) ).put( char( (l_iSizeX & 0xFF00) >> 8 ) );
		l_imageFile.put( char( l_iSizeY & 0x00FF ) ).put( char( (l_iSizeY & 0xFF00) >> 8 ) );
		l_imageFile.put( 24	);       /* 24 bit bitmap */
		l_imageFile.put( 0	);
		// fin du header TGA
		uint8_t l_r, l_g, l_b;

		// balayage
		for (int y = 0; y < l_iSizeY; ++y)
		{
			Logger::LogMessage( cuT( "y : %i"), y);
			for (int x = 0; x < l_iSizeX; ++x)
			{
				Colour l_clrColour;
				real coef = 1.0f;
				int level = 0;
				// lancer de rayon
				Ray l_viewRay( Point3r( real( x - 128 ), real( y - 128 ), real( -10000.0 ) ), Point3r( 0, 0, 1 ) );

				SceneNodePtrStrMap::const_iterator l_itNodesEnd = m_pScene->NodesEnd();
				LightPtrIntMap::const_iterator l_itLightsEnd = m_pScene->LightsEnd();
				Geometry * l_pNearestGeometry = nullptr;
				SubmeshSPtr l_pNearestSubmesh;

				do
				{
					// recherche de l'intersection la plus proche
					real l_fDistance = 20000.0f;
					FaceSPtr l_pFace;

					for (SceneNodePtrStrMap::iterator l_it = m_pScene->NodesBegin(); l_it != l_itNodesEnd; ++l_it)
					{
						l_pNearestGeometry = l_it->second->GetNearestGeometry( & l_viewRay, l_fDistance, & l_pFace, & l_pNearestSubmesh);
					}

					if (l_pNearestGeometry)
					{
//						Logger::LogMessage( cuT( "Geometry : ") + l_pNearestGeometry->GetName());
						Point3r l_vNewStart( l_viewRay.m_ptOrigin + (l_viewRay.m_ptDirection * l_fDistance));
						// la normale au point d'intersection
						Point3r l_vNormal( l_vNewStart - l_pNearestSubmesh->GetSphere().GetCenter());
//						Point3r l_vNormal( l_pFace->m_ptFaceNormal);
						real l_fTemp = point::dot( l_vNormal, l_vNormal);

						if (l_fTemp == 0.0f)
						{
							break;
						}

						l_fTemp = real( 1.0) / std::sqrt( l_fTemp );
						l_vNormal *= l_fTemp;

						MaterialSPtr l_pCurrentMat = l_pNearestSubmesh->GetMaterial();

						// calcul de la valeur d'éclairement au point
						for (LightPtrIntMap::iterator l_it = m_pScene->LightsBegin(); l_it != l_itLightsEnd; ++l_it)
						{
							LightSPtr l_pCurrent = l_it->second;
							Point3r l_vDist( l_pCurrent->GetParent()->GetPosition() - l_vNewStart);

							if( point::dot( l_vNormal, l_vDist ) > 0 )
							{
								real l_fT = real( point::distance( l_vDist ) );

								if (l_fT > 0.0f)
								{
									Ray l_lightRay( l_vNewStart, l_vDist * (1 / l_fT));
									// calcul des ombres
									bool l_bInShadow = false;

									for (SceneNodePtrStrMap::iterator l_it = m_pScene->NodesBegin(); ! l_bInShadow && l_it != l_itNodesEnd; ++l_it)
									{
										l_pNearestGeometry = l_it->second->GetNearestGeometry( & l_lightRay, l_fT, nullptr, nullptr);

										if (l_pNearestGeometry)
										{
											l_bInShadow = true;
										}
									}

									if ( ! l_bInShadow)
									{
										// lambert
										float l_fLambert = float( point::dot( l_lightRay.m_ptDirection, l_vNormal ) * coef );
										l_clrColour.red()	+= l_pCurrent->GetDiffuse().red()	* l_pCurrentMat->GetPass( 0 )->GetDiffuse().red()	* l_fLambert;
										l_clrColour.green()	+= l_pCurrent->GetDiffuse().green()	* l_pCurrentMat->GetPass( 0 )->GetDiffuse().green()	* l_fLambert;
										l_clrColour.blue()	+= l_pCurrent->GetDiffuse().blue()	* l_pCurrentMat->GetPass( 0 )->GetDiffuse().blue()	* l_fLambert;
									}
								}
							}
						}

						// on itére sur la prochaine reflexion
						coef *= l_pCurrentMat->GetPass( 0)->GetShininess();

						real l_fReflet = 2.0f * point::dot( l_viewRay.m_ptDirection, l_vNormal );
						l_viewRay.m_ptOrigin = l_vNewStart;
						l_viewRay.m_ptDirection = l_viewRay.m_ptDirection - (l_vNormal * l_fReflet);

						level++;
					}
				}
				while ((coef > 0.0f) && (level < 10) && l_pNearestGeometry);
				
				l_imageFile.put( l_clrColour.blue().convert_to( l_b ) ).put( l_clrColour.green().convert_to( l_g ) ).put( l_clrColour.red().convert_to( l_r ) );
			}
		}

		l_bReturn = true;
	}

	return l_bReturn;
}

#pragma warning( pop )