185 lines
6.8 KiB
C++
185 lines
6.8 KiB
C++
/*
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---------------------------------------------------------------------------
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Open Asset Import Library (assimp)
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---------------------------------------------------------------------------
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Copyright (c) 2006-2019, assimp team
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All rights reserved.
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Redistribution and use of this software in source and binary forms,
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with or without modification, are permitted provided that the following
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conditions are met:
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* Redistributions of source code must retain the above
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copyright notice, this list of conditions and the
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following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the
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following disclaimer in the documentation and/or other
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materials provided with the distribution.
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* Neither the name of the assimp team, nor the names of its
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contributors may be used to endorse or promote products
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derived from this software without specific prior
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written permission of the assimp team.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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---------------------------------------------------------------------------
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*/
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/** @file Implementation of the post processing step to invert
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* all normals in meshes with infacing normals.
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*/
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// internal headers
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#include "FixNormalsStep.h"
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#include <assimp/StringUtils.h>
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#include <assimp/DefaultLogger.hpp>
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#include <assimp/postprocess.h>
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#include <assimp/scene.h>
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#include <stdio.h>
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using namespace Assimp;
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// ------------------------------------------------------------------------------------------------
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// Constructor to be privately used by Importer
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FixInfacingNormalsProcess::FixInfacingNormalsProcess()
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{
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// nothing to do here
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}
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// ------------------------------------------------------------------------------------------------
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// Destructor, private as well
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FixInfacingNormalsProcess::~FixInfacingNormalsProcess()
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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 FixInfacingNormalsProcess::IsActive( unsigned int pFlags) const
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{
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return (pFlags & aiProcess_FixInfacingNormals) != 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 FixInfacingNormalsProcess::Execute( aiScene* pScene)
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{
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ASSIMP_LOG_DEBUG("FixInfacingNormalsProcess begin");
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bool bHas( false );
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for (unsigned int a = 0; a < pScene->mNumMeshes; ++a) {
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if (ProcessMesh(pScene->mMeshes[a], a)) {
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bHas = true;
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}
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}
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if (bHas) {
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ASSIMP_LOG_DEBUG("FixInfacingNormalsProcess finished. Found issues.");
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} else {
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ASSIMP_LOG_DEBUG("FixInfacingNormalsProcess finished. No changes to the scene.");
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}
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}
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// ------------------------------------------------------------------------------------------------
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// Apply the step to the mesh
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bool FixInfacingNormalsProcess::ProcessMesh( aiMesh* pcMesh, unsigned int index)
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{
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ai_assert(nullptr != pcMesh);
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// Nothing to do if there are no model normals
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if (!pcMesh->HasNormals()) {
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return false;
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}
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// Compute the bounding box of both the model vertices + normals and
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// the unmodified model vertices. Then check whether the first BB
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// is smaller than the second. In this case we can assume that the
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// normals need to be flipped, although there are a few special cases ..
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// convex, concave, planar models ...
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aiVector3D vMin0 (1e10f,1e10f,1e10f);
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aiVector3D vMin1 (1e10f,1e10f,1e10f);
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aiVector3D vMax0 (-1e10f,-1e10f,-1e10f);
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aiVector3D vMax1 (-1e10f,-1e10f,-1e10f);
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for (unsigned int i = 0; i < pcMesh->mNumVertices;++i)
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{
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vMin1.x = std::min(vMin1.x,pcMesh->mVertices[i].x);
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vMin1.y = std::min(vMin1.y,pcMesh->mVertices[i].y);
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vMin1.z = std::min(vMin1.z,pcMesh->mVertices[i].z);
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vMax1.x = std::max(vMax1.x,pcMesh->mVertices[i].x);
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vMax1.y = std::max(vMax1.y,pcMesh->mVertices[i].y);
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vMax1.z = std::max(vMax1.z,pcMesh->mVertices[i].z);
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const aiVector3D vWithNormal = pcMesh->mVertices[i] + pcMesh->mNormals[i];
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vMin0.x = std::min(vMin0.x,vWithNormal.x);
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vMin0.y = std::min(vMin0.y,vWithNormal.y);
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vMin0.z = std::min(vMin0.z,vWithNormal.z);
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vMax0.x = std::max(vMax0.x,vWithNormal.x);
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vMax0.y = std::max(vMax0.y,vWithNormal.y);
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vMax0.z = std::max(vMax0.z,vWithNormal.z);
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}
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const float fDelta0_x = (vMax0.x - vMin0.x);
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const float fDelta0_y = (vMax0.y - vMin0.y);
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const float fDelta0_z = (vMax0.z - vMin0.z);
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const float fDelta1_x = (vMax1.x - vMin1.x);
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const float fDelta1_y = (vMax1.y - vMin1.y);
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const float fDelta1_z = (vMax1.z - vMin1.z);
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// Check whether the boxes are overlapping
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if ((fDelta0_x > 0.0f) != (fDelta1_x > 0.0f))return false;
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if ((fDelta0_y > 0.0f) != (fDelta1_y > 0.0f))return false;
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if ((fDelta0_z > 0.0f) != (fDelta1_z > 0.0f))return false;
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// Check whether this is a planar surface
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const float fDelta1_yz = fDelta1_y * fDelta1_z;
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if (fDelta1_x < 0.05f * std::sqrt( fDelta1_yz ))return false;
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if (fDelta1_y < 0.05f * std::sqrt( fDelta1_z * fDelta1_x ))return false;
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if (fDelta1_z < 0.05f * std::sqrt( fDelta1_y * fDelta1_x ))return false;
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// now compare the volumes of the bounding boxes
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if (std::fabs(fDelta0_x * fDelta0_y * fDelta0_z) < std::fabs(fDelta1_x * fDelta1_yz)) {
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if (!DefaultLogger::isNullLogger()) {
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ASSIMP_LOG_INFO_F("Mesh ", index, ": Normals are facing inwards (or the mesh is planar)", index);
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}
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// Invert normals
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for (unsigned int i = 0; i < pcMesh->mNumVertices;++i)
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pcMesh->mNormals[i] *= -1.0f;
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// ... and flip faces
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for (unsigned int i = 0; i < pcMesh->mNumFaces;++i)
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{
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aiFace& face = pcMesh->mFaces[i];
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for( unsigned int b = 0; b < face.mNumIndices / 2; b++)
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std::swap( face.mIndices[b], face.mIndices[ face.mNumIndices - 1 - b]);
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}
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return true;
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}
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return false;
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}
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