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3Open Asset Import Library (assimp)
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41
42/** @file Generation of normal vectors basing on smoothing groups */
43
44#ifndef AI_SMOOTHINGGROUPS_INL_INCLUDED
45#define AI_SMOOTHINGGROUPS_INL_INCLUDED
46
47// internal headers
48#include "SGSpatialSort.h"
49
50// CRT header
51#include <algorithm>
52
53using namespace Assimp;
54
55// ------------------------------------------------------------------------------------------------
56template <class T>
57void ComputeNormalsWithSmoothingsGroups(MeshWithSmoothingGroups<T>& sMesh)
58{
59	// First generate face normals
60	sMesh.mNormals.resize(sMesh.mPositions.size(),aiVector3D());
61	for( unsigned int a = 0; a < sMesh.mFaces.size(); a++)
62	{
63		T& face = sMesh.mFaces[a];
64
65		aiVector3D* pV1 = &sMesh.mPositions[face.mIndices[0]];
66		aiVector3D* pV2 = &sMesh.mPositions[face.mIndices[1]];
67		aiVector3D* pV3 = &sMesh.mPositions[face.mIndices[2]];
68
69		aiVector3D pDelta1 = *pV2 - *pV1;
70		aiVector3D pDelta2 = *pV3 - *pV1;
71		aiVector3D vNor = pDelta1 ^ pDelta2;
72
73		for (unsigned int c = 0; c < 3;++c)
74			sMesh.mNormals[face.mIndices[c]] = vNor;
75	}
76
77	// calculate the position bounds so we have a reliable epsilon to check position differences against
78	aiVector3D minVec( 1e10f, 1e10f, 1e10f), maxVec( -1e10f, -1e10f, -1e10f);
79	for( unsigned int a = 0; a < sMesh.mPositions.size(); a++)
80	{
81		minVec.x = std::min( minVec.x, sMesh.mPositions[a].x);
82		minVec.y = std::min( minVec.y, sMesh.mPositions[a].y);
83		minVec.z = std::min( minVec.z, sMesh.mPositions[a].z);
84		maxVec.x = std::max( maxVec.x, sMesh.mPositions[a].x);
85		maxVec.y = std::max( maxVec.y, sMesh.mPositions[a].y);
86		maxVec.z = std::max( maxVec.z, sMesh.mPositions[a].z);
87	}
88	const float posEpsilon = (maxVec - minVec).Length() * 1e-5f;
89	std::vector<aiVector3D> avNormals;
90	avNormals.resize(sMesh.mNormals.size());
91
92	// now generate the spatial sort tree
93	SGSpatialSort sSort;
94	for( typename std::vector<T>::iterator i =  sMesh.mFaces.begin();
95		i != sMesh.mFaces.end();++i)
96	{
97		for (unsigned int c = 0; c < 3;++c)
98			sSort.Add(sMesh.mPositions[(*i).mIndices[c]],(*i).mIndices[c],(*i).iSmoothGroup);
99	}
100	sSort.Prepare();
101
102	std::vector<bool> vertexDone(sMesh.mPositions.size(),false);
103	for( typename std::vector<T>::iterator i =  sMesh.mFaces.begin();
104		i != sMesh.mFaces.end();++i)
105	{
106		std::vector<unsigned int> poResult;
107		for (unsigned int c = 0; c < 3;++c)
108		{
109			register unsigned int idx = (*i).mIndices[c];
110			if (vertexDone[idx])continue;
111
112			sSort.FindPositions(sMesh.mPositions[idx],(*i).iSmoothGroup,
113				posEpsilon,poResult);
114
115			aiVector3D vNormals;
116			for (std::vector<unsigned int>::const_iterator
117				a =  poResult.begin();
118				a != poResult.end();++a)
119			{
120				vNormals += sMesh.mNormals[(*a)];
121			}
122			vNormals.Normalize();
123
124			// write back into all affected normals
125			for (std::vector<unsigned int>::const_iterator
126				a =  poResult.begin();
127				a != poResult.end();++a)
128			{
129				idx = *a;
130				avNormals [idx] = vNormals;
131				vertexDone[idx] = true;
132			}
133		}
134	}
135	sMesh.mNormals = avNormals;
136}
137
138#endif // !! AI_SMOOTHINGGROUPS_INL_INCLUDED
139