/*
---------------------------------------------------------------------------
Open Asset Import Library (ASSIMP)
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Copyright (c) 2006-2008, ASSIMP Development Team

All rights reserved.

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* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
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* Neither the name of the ASSIMP team, nor the names of its
  contributors may be used to endorse or promote products
  derived from this software without specific prior
  written permission of the ASSIMP Development Team.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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*/

/** @file Implementation of the 3ds importer class */
#include "3DSLoader.h"
#include "MaterialSystem.h"
#include <algorithm>
#include "../include/IOStream.h"
#include "../include/IOSystem.h"
#include "../include/aiMesh.h"
#include "../include/aiScene.h"
#include "../include/aiAssert.h"
#include "3DSSpatialSort.h"

using namespace Assimp;

// ------------------------------------------------------------------------------------------------
void Dot3DSImporter::GenNormals(Dot3DS::Mesh* sMesh)
{
	// First generate face normals
	sMesh->mNormals.resize(sMesh->mPositions.size(),aiVector3D());
	for( unsigned int a = 0; a < sMesh->mFaces.size(); a++)
	{
		Dot3DS::Face& face = sMesh->mFaces[a];

		// assume it is a triangle
		aiVector3D* pV1 = &sMesh->mPositions[face.mIndices[0]];
		aiVector3D* pV2 = &sMesh->mPositions[face.mIndices[1]];
		aiVector3D* pV3 = &sMesh->mPositions[face.mIndices[2]];

		// FIX invert all vertex normals
		aiVector3D pDelta1 = *pV3 - *pV1;
		aiVector3D pDelta2 = *pV2 - *pV1;
		aiVector3D vNor = pDelta1 ^ pDelta2;

		sMesh->mNormals[face.mIndices[0]] = vNor;
		sMesh->mNormals[face.mIndices[1]] = vNor;
		sMesh->mNormals[face.mIndices[2]] = vNor;
	}

	// calculate the position bounds so we have a reliable epsilon to 
	// check position differences against 
	// @Schrompf: This is the 6th time this snippet is repeated!
	aiVector3D minVec( 1e10f, 1e10f, 1e10f), maxVec( -1e10f, -1e10f, -1e10f);
	for( unsigned int a = 0; a < sMesh->mPositions.size(); a++)
	{
		minVec.x = std::min( minVec.x, sMesh->mPositions[a].x);
		minVec.y = std::min( minVec.y, sMesh->mPositions[a].y);
		minVec.z = std::min( minVec.z, sMesh->mPositions[a].z);
		maxVec.x = std::max( maxVec.x, sMesh->mPositions[a].x);
		maxVec.y = std::max( maxVec.y, sMesh->mPositions[a].y);
		maxVec.z = std::max( maxVec.z, sMesh->mPositions[a].z);
	}
	const float posEpsilon = (maxVec - minVec).Length() * 1e-5f;
	std::vector<aiVector3D> avNormals;
	avNormals.resize(sMesh->mNormals.size());
	
	// now generate the spatial sort tree
	D3DSSpatialSorter sSort;
	for( std::vector<Dot3DS::Face>::iterator
		i =  sMesh->mFaces.begin();
		i != sMesh->mFaces.end();++i)
	{
		sSort.AddFace(&(*i),sMesh->mPositions);
	}
	sSort.Prepare();

	for( std::vector<Dot3DS::Face>::iterator
		i =  sMesh->mFaces.begin();
		i != sMesh->mFaces.end();++i)
	{
		std::vector<unsigned int> poResult;

		for (unsigned int c = 0; c < 3;++c)
		{

			sSort.FindPositions(sMesh->mPositions[(*i).mIndices[c]],(*i).iSmoothGroup,
				posEpsilon,poResult);

			aiVector3D vNormals;
			float fDiv = 0.0f;
			for (std::vector<unsigned int>::const_iterator
				a =  poResult.begin();
				a != poResult.end();++a)
			{
				vNormals += sMesh->mNormals[(*a)];
				fDiv += 1.0f;
			}
			vNormals.x /= fDiv;
			vNormals.y /= fDiv;
			vNormals.z /= fDiv;
			vNormals.Normalize();

			// do the common coordinate system adjustment
			std::swap(vNormals.y,vNormals.z);

			avNormals[(*i).mIndices[c]] = vNormals;
			poResult.clear();
		}
	}
	sMesh->mNormals = avNormals;
	return;
}