assimp/code/GenFaceNormalsProcess.cpp

67 lines
2.0 KiB
C++

/** @file Implementation of the post processing step to generate face
* normals for all imported faces.
*/
#include "GenFaceNormalsProcess.h"
#include "../include/aiPostProcess.h"
#include "../include/aiMesh.h"
#include "../include/aiScene.h"
using namespace Assimp;
// Constructor to be privately used by Importer
GenFaceNormalsProcess::GenFaceNormalsProcess()
{
}
// Destructor, private as well
GenFaceNormalsProcess::~GenFaceNormalsProcess()
{
// nothing to do here
}
// -------------------------------------------------------------------
// Returns whether the processing step is present in the given flag field.
bool GenFaceNormalsProcess::IsActive( unsigned int pFlags) const
{
return (pFlags & aiProcess_GenNormals) != 0;
}
// -------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void GenFaceNormalsProcess::Execute( aiScene* pScene)
{
for( unsigned int a = 0; a < pScene->mNumMeshes; a++)
this->GenMeshFaceNormals( pScene->mMeshes[a]);
}
// -------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void GenFaceNormalsProcess::GenMeshFaceNormals (aiMesh* pMesh)
{
if (NULL != pMesh->mNormals)return;
pMesh->mNormals = new aiVector3D[pMesh->mNumVertices];
for( unsigned int a = 0; a < pMesh->mNumFaces; a++)
{
const aiFace& face = pMesh->mFaces[a];
// assume it is a triangle
aiVector3D* pV1 = &pMesh->mVertices[face.mIndices[0]];
aiVector3D* pV2 = &pMesh->mVertices[face.mIndices[1]];
aiVector3D* pV3 = &pMesh->mVertices[face.mIndices[2]];
aiVector3D pDelta1 = *pV2 - *pV1;
aiVector3D pDelta2 = *pV3 - *pV1;
aiVector3D vNor = pDelta1 ^ pDelta2;
// NOTE: Never normalize here. Causes problems ...
//float fLength = vNor.Length();
//if (0.0f != fLength)vNor /= fLength;
pMesh->mNormals[face.mIndices[0]] = vNor;
pMesh->mNormals[face.mIndices[1]] = vNor;
pMesh->mNormals[face.mIndices[2]] = vNor;
}
return;
}