104 lines
3.5 KiB
C++
104 lines
3.5 KiB
C++
/** @file Implementation of the post processing step to generate face
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* normals for all imported faces.
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*/
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#include "GenVertexNormalsProcess.h"
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#include "SpatialSort.h"
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#include "../include/aiPostProcess.h"
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#include "../include/aiMesh.h"
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#include "../include/aiScene.h"
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using namespace Assimp;
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// Constructor to be privately used by Importer
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GenVertexNormalsProcess::GenVertexNormalsProcess()
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{
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}
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// Destructor, private as well
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GenVertexNormalsProcess::~GenVertexNormalsProcess()
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{
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// nothing to do here
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}
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// -------------------------------------------------------------------
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// Returns whether the processing step is present in the given flag field.
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bool GenVertexNormalsProcess::IsActive( unsigned int pFlags) const
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{
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return (pFlags & aiProcess_GenSmoothNormals) != 0;
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}
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// -------------------------------------------------------------------
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// Executes the post processing step on the given imported data.
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void GenVertexNormalsProcess::Execute( aiScene* pScene)
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{
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for( unsigned int a = 0; a < pScene->mNumMeshes; a++)
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this->GenMeshVertexNormals( pScene->mMeshes[a]);
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}
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// -------------------------------------------------------------------
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// Executes the post processing step on the given imported data.
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void GenVertexNormalsProcess::GenMeshVertexNormals (aiMesh* pMesh)
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{
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if (NULL != pMesh->mNormals)return;
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pMesh->mNormals = new aiVector3D[pMesh->mNumVertices];
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for( unsigned int a = 0; a < pMesh->mNumFaces; a++)
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{
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const aiFace& face = pMesh->mFaces[a];
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// assume it is a triangle
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aiVector3D* pV1 = &pMesh->mVertices[face.mIndices[0]];
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aiVector3D* pV2 = &pMesh->mVertices[face.mIndices[1]];
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aiVector3D* pV3 = &pMesh->mVertices[face.mIndices[2]];
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aiVector3D pDelta1 = *pV2 - *pV1;
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aiVector3D pDelta2 = *pV3 - *pV1;
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aiVector3D vNor = pDelta1 ^ pDelta2;
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float fLength = vNor.Length();
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if (0.0f != fLength)vNor /= fLength;
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pMesh->mNormals[face.mIndices[0]] = vNor;
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pMesh->mNormals[face.mIndices[1]] = vNor;
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pMesh->mNormals[face.mIndices[2]] = vNor;
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}
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// calculate the position bounds so we have a reliable epsilon to
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// check position differences against
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aiVector3D minVec( 1e10f, 1e10f, 1e10f), maxVec( -1e10f, -1e10f, -1e10f);
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for( unsigned int a = 0; a < pMesh->mNumVertices; a++)
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{
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minVec.x = std::min( minVec.x, pMesh->mVertices[a].x);
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minVec.y = std::min( minVec.y, pMesh->mVertices[a].y);
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minVec.z = std::min( minVec.z, pMesh->mVertices[a].z);
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maxVec.x = std::max( maxVec.x, pMesh->mVertices[a].x);
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maxVec.y = std::max( maxVec.y, pMesh->mVertices[a].y);
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maxVec.z = std::max( maxVec.z, pMesh->mVertices[a].z);
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}
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const float posEpsilon = (maxVec - minVec).Length() * 1e-5f;
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// set up a SpatialSort to quickly find all vertices close to a given position
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SpatialSort vertexFinder( pMesh->mVertices, pMesh->mNumVertices, sizeof( aiVector3D));
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std::vector<unsigned int> verticesFound;
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aiVector3D* pcNew = new aiVector3D[pMesh->mNumVertices];
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for (unsigned int i = 0; i < pMesh->mNumVertices;++i)
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{
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const aiVector3D& posThis = pMesh->mVertices[i];
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// get all vertices that share this one ...
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vertexFinder.FindPositions( posThis, posEpsilon, verticesFound);
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aiVector3D pcNor;
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for (unsigned int a = 0; a < verticesFound.size(); ++a)
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{
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unsigned int vidx = verticesFound[a];
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pcNor += pMesh->mNormals[vidx];
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}
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pcNor /= (float) verticesFound.size();
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pcNew[i] = pcNor;
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}
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delete pMesh->mNormals;
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pMesh->mNormals = pcNew;
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return;
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} |