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3Open Asset Import Library (assimp)
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40*/
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 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.NormalizeSafe();
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