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Open Asset Import Library (assimp)
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*/

/** @file Implementation of the post processing step to drop face
* normals for all imported faces.
*/


#include "DropFaceNormalsProcess.h"
#include <assimp/postprocess.h>
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>
#include <assimp/Exceptional.h>

using namespace Assimp;

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
DropFaceNormalsProcess::DropFaceNormalsProcess()
{
    // nothing to do here
}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
DropFaceNormalsProcess::~DropFaceNormalsProcess()
{
    // nothing to do here
}

// ------------------------------------------------------------------------------------------------
// Returns whether the processing step is present in the given flag field.
bool DropFaceNormalsProcess::IsActive( unsigned int pFlags) const {
    return  (pFlags & aiProcess_DropNormals) != 0;
}

// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void DropFaceNormalsProcess::Execute( aiScene* pScene) {
    ASSIMP_LOG_DEBUG("DropFaceNormalsProcess begin");

    if (pScene->mFlags & AI_SCENE_FLAGS_NON_VERBOSE_FORMAT) {
        throw DeadlyImportError("Post-processing order mismatch: expecting pseudo-indexed (\"verbose\") vertices here");
    }

    bool bHas = false;
    for( unsigned int a = 0; a < pScene->mNumMeshes; a++) {
        bHas |= this->DropMeshFaceNormals( pScene->mMeshes[a]);
    }
    if (bHas)   {
        ASSIMP_LOG_INFO("DropFaceNormalsProcess finished. "
            "Face normals have been removed");
    } else {
        ASSIMP_LOG_DEBUG("DropFaceNormalsProcess finished. "
            "No normals were present");
    }
}

// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
bool DropFaceNormalsProcess::DropMeshFaceNormals (aiMesh* mesh) {
    ai_assert(nullptr != mesh);

    if (nullptr == mesh->mNormals) {
        return false;
    }
    
    delete[] mesh->mNormals;
    mesh->mNormals = nullptr;
    return true;
}
