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320 lines
13 KiB
C++
320 lines
13 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 calculate
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* tangents and bitangents for all imported meshes
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*/
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// internal headers
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#include "CalcTangentsProcess.h"
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#include "ProcessHelper.h"
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#include <assimp/TinyFormatter.h>
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#include <assimp/qnan.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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CalcTangentsProcess::CalcTangentsProcess()
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: configMaxAngle( AI_DEG_TO_RAD(45.f) )
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, configSourceUV( 0 ) {
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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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CalcTangentsProcess::~CalcTangentsProcess()
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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 CalcTangentsProcess::IsActive( unsigned int pFlags) const
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{
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return (pFlags & aiProcess_CalcTangentSpace) != 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 CalcTangentsProcess::SetupProperties(const Importer* pImp)
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{
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ai_assert( NULL != pImp );
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// get the current value of the property
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configMaxAngle = pImp->GetPropertyFloat(AI_CONFIG_PP_CT_MAX_SMOOTHING_ANGLE,45.f);
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configMaxAngle = std::max(std::min(configMaxAngle,45.0f),0.0f);
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configMaxAngle = AI_DEG_TO_RAD(configMaxAngle);
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configSourceUV = pImp->GetPropertyInteger(AI_CONFIG_PP_CT_TEXTURE_CHANNEL_INDEX,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 CalcTangentsProcess::Execute( aiScene* pScene)
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{
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ai_assert( NULL != pScene );
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ASSIMP_LOG_DEBUG("CalcTangentsProcess 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))bHas = true;
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}
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if ( bHas ) {
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ASSIMP_LOG_INFO("CalcTangentsProcess finished. Tangents have been calculated");
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} else {
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ASSIMP_LOG_DEBUG("CalcTangentsProcess finished");
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}
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}
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// ------------------------------------------------------------------------------------------------
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// Calculates tangents and bi-tangents for the given mesh
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bool CalcTangentsProcess::ProcessMesh( aiMesh* pMesh, unsigned int meshIndex)
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{
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// we assume that the mesh is still in the verbose vertex format where each face has its own set
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// of vertices and no vertices are shared between faces. Sadly I don't know any quick test to
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// assert() it here.
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// assert( must be verbose, dammit);
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if (pMesh->mTangents) // this implies that mBitangents is also there
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return false;
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// If the mesh consists of lines and/or points but not of
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// triangles or higher-order polygons the normal vectors
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// are undefined.
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if (!(pMesh->mPrimitiveTypes & (aiPrimitiveType_TRIANGLE | aiPrimitiveType_POLYGON)))
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{
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ASSIMP_LOG_INFO("Tangents are undefined for line and point meshes");
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return false;
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}
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// what we can check, though, is if the mesh has normals and texture coordinates. That's a requirement
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if( pMesh->mNormals == NULL)
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{
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ASSIMP_LOG_ERROR("Failed to compute tangents; need normals");
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return false;
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}
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if( configSourceUV >= AI_MAX_NUMBER_OF_TEXTURECOORDS || !pMesh->mTextureCoords[configSourceUV] )
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{
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ASSIMP_LOG_ERROR((Formatter::format("Failed to compute tangents; need UV data in channel"),configSourceUV));
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return false;
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}
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const float angleEpsilon = 0.9999f;
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std::vector<bool> vertexDone( pMesh->mNumVertices, false);
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const float qnan = get_qnan();
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// create space for the tangents and bitangents
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pMesh->mTangents = new aiVector3D[pMesh->mNumVertices];
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pMesh->mBitangents = new aiVector3D[pMesh->mNumVertices];
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const aiVector3D* meshPos = pMesh->mVertices;
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const aiVector3D* meshNorm = pMesh->mNormals;
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const aiVector3D* meshTex = pMesh->mTextureCoords[configSourceUV];
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aiVector3D* meshTang = pMesh->mTangents;
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aiVector3D* meshBitang = pMesh->mBitangents;
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// calculate the tangent and bitangent for every face
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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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if (face.mNumIndices < 3)
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{
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// There are less than three indices, thus the tangent vector
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// is not defined. We are finished with these vertices now,
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// their tangent vectors are set to qnan.
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for (unsigned int i = 0; i < face.mNumIndices;++i)
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{
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unsigned int idx = face.mIndices[i];
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vertexDone [idx] = true;
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meshTang [idx] = aiVector3D(qnan);
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meshBitang [idx] = aiVector3D(qnan);
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}
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continue;
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}
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// triangle or polygon... we always use only the first three indices. A polygon
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// is supposed to be planar anyways....
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// FIXME: (thom) create correct calculation for multi-vertex polygons maybe?
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const unsigned int p0 = face.mIndices[0], p1 = face.mIndices[1], p2 = face.mIndices[2];
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// position differences p1->p2 and p1->p3
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aiVector3D v = meshPos[p1] - meshPos[p0], w = meshPos[p2] - meshPos[p0];
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// texture offset p1->p2 and p1->p3
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float sx = meshTex[p1].x - meshTex[p0].x, sy = meshTex[p1].y - meshTex[p0].y;
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float tx = meshTex[p2].x - meshTex[p0].x, ty = meshTex[p2].y - meshTex[p0].y;
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float dirCorrection = (tx * sy - ty * sx) < 0.0f ? -1.0f : 1.0f;
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// when t1, t2, t3 in same position in UV space, just use default UV direction.
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if ( sx * ty == sy * tx ) {
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sx = 0.0; sy = 1.0;
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tx = 1.0; ty = 0.0;
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}
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// tangent points in the direction where to positive X axis of the texture coord's would point in model space
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// bitangent's points along the positive Y axis of the texture coord's, respectively
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aiVector3D tangent, bitangent;
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tangent.x = (w.x * sy - v.x * ty) * dirCorrection;
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tangent.y = (w.y * sy - v.y * ty) * dirCorrection;
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tangent.z = (w.z * sy - v.z * ty) * dirCorrection;
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bitangent.x = (w.x * sx - v.x * tx) * dirCorrection;
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bitangent.y = (w.y * sx - v.y * tx) * dirCorrection;
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bitangent.z = (w.z * sx - v.z * tx) * dirCorrection;
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// store for every vertex of that face
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for( unsigned int b = 0; b < face.mNumIndices; ++b ) {
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unsigned int p = face.mIndices[b];
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// project tangent and bitangent into the plane formed by the vertex' normal
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aiVector3D localTangent = tangent - meshNorm[p] * (tangent * meshNorm[p]);
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aiVector3D localBitangent = bitangent - meshNorm[p] * (bitangent * meshNorm[p]);
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localTangent.Normalize(); localBitangent.Normalize();
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// reconstruct tangent/bitangent according to normal and bitangent/tangent when it's infinite or NaN.
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bool invalid_tangent = is_special_float(localTangent.x) || is_special_float(localTangent.y) || is_special_float(localTangent.z);
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bool invalid_bitangent = is_special_float(localBitangent.x) || is_special_float(localBitangent.y) || is_special_float(localBitangent.z);
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if (invalid_tangent != invalid_bitangent) {
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if (invalid_tangent) {
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localTangent = meshNorm[p] ^ localBitangent;
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localTangent.Normalize();
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} else {
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localBitangent = localTangent ^ meshNorm[p];
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localBitangent.Normalize();
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}
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}
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// and write it into the mesh.
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meshTang[ p ] = localTangent;
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meshBitang[ p ] = localBitangent;
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}
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}
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// create a helper to quickly find locally close vertices among the vertex array
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// FIX: check whether we can reuse the SpatialSort of a previous step
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SpatialSort* vertexFinder = NULL;
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SpatialSort _vertexFinder;
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float posEpsilon;
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if (shared)
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{
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std::vector<std::pair<SpatialSort,float> >* avf;
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shared->GetProperty(AI_SPP_SPATIAL_SORT,avf);
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if (avf)
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{
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std::pair<SpatialSort,float>& blubb = avf->operator [] (meshIndex);
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vertexFinder = &blubb.first;
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posEpsilon = blubb.second;;
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}
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}
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if (!vertexFinder)
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{
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_vertexFinder.Fill(pMesh->mVertices, pMesh->mNumVertices, sizeof( aiVector3D));
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vertexFinder = &_vertexFinder;
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posEpsilon = ComputePositionEpsilon(pMesh);
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}
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std::vector<unsigned int> verticesFound;
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const float fLimit = std::cos(configMaxAngle);
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std::vector<unsigned int> closeVertices;
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// in the second pass we now smooth out all tangents and bitangents at the same local position
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// if they are not too far off.
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for( unsigned int a = 0; a < pMesh->mNumVertices; a++)
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{
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if( vertexDone[a])
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continue;
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const aiVector3D& origPos = pMesh->mVertices[a];
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const aiVector3D& origNorm = pMesh->mNormals[a];
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const aiVector3D& origTang = pMesh->mTangents[a];
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const aiVector3D& origBitang = pMesh->mBitangents[a];
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closeVertices.resize( 0 );
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// find all vertices close to that position
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vertexFinder->FindPositions( origPos, posEpsilon, verticesFound);
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closeVertices.reserve (verticesFound.size()+5);
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closeVertices.push_back( a);
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// look among them for other vertices sharing the same normal and a close-enough tangent/bitangent
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for( unsigned int b = 0; b < verticesFound.size(); b++)
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{
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unsigned int idx = verticesFound[b];
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if( vertexDone[idx])
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continue;
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if( meshNorm[idx] * origNorm < angleEpsilon)
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continue;
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if( meshTang[idx] * origTang < fLimit)
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continue;
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if( meshBitang[idx] * origBitang < fLimit)
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continue;
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// it's similar enough -> add it to the smoothing group
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closeVertices.push_back( idx);
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vertexDone[idx] = true;
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}
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// smooth the tangents and bitangents of all vertices that were found to be close enough
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aiVector3D smoothTangent( 0, 0, 0), smoothBitangent( 0, 0, 0);
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for( unsigned int b = 0; b < closeVertices.size(); ++b)
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{
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smoothTangent += meshTang[ closeVertices[b] ];
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smoothBitangent += meshBitang[ closeVertices[b] ];
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}
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smoothTangent.Normalize();
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smoothBitangent.Normalize();
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// and write it back into all affected tangents
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for( unsigned int b = 0; b < closeVertices.size(); ++b)
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{
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meshTang[ closeVertices[b] ] = smoothTangent;
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meshBitang[ closeVertices[b] ] = smoothBitangent;
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}
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}
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return true;
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}
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