Urho3D/Source/ThirdParty/Assimp/code/CalcTangentsProcess.cpp

319 lines
13 KiB
C++

/*
---------------------------------------------------------------------------
Open Asset Import Library (assimp)
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Copyright (c) 2006-2017, assimp team
All rights reserved.
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* Redistributions in binary form must reproduce the above
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* Neither the name of the assimp team, nor the names of its
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derived from this software without specific prior
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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*/
/** @file Implementation of the post processing step to calculate
* tangents and bitangents for all imported meshes
*/
// internal headers
#include "CalcTangentsProcess.h"
#include "ProcessHelper.h"
#include "TinyFormatter.h"
#include "qnan.h"
using namespace Assimp;
// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
CalcTangentsProcess::CalcTangentsProcess()
: configMaxAngle( AI_DEG_TO_RAD(45.f) )
, configSourceUV( 0 ) {
// nothing to do here
}
// ------------------------------------------------------------------------------------------------
// Destructor, private as well
CalcTangentsProcess::~CalcTangentsProcess()
{
// nothing to do here
}
// ------------------------------------------------------------------------------------------------
// Returns whether the processing step is present in the given flag field.
bool CalcTangentsProcess::IsActive( unsigned int pFlags) const
{
return (pFlags & aiProcess_CalcTangentSpace) != 0;
}
// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void CalcTangentsProcess::SetupProperties(const Importer* pImp)
{
ai_assert( NULL != pImp );
// get the current value of the property
configMaxAngle = pImp->GetPropertyFloat(AI_CONFIG_PP_CT_MAX_SMOOTHING_ANGLE,45.f);
configMaxAngle = std::max(std::min(configMaxAngle,45.0f),0.0f);
configMaxAngle = AI_DEG_TO_RAD(configMaxAngle);
configSourceUV = pImp->GetPropertyInteger(AI_CONFIG_PP_CT_TEXTURE_CHANNEL_INDEX,0);
}
// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void CalcTangentsProcess::Execute( aiScene* pScene)
{
ai_assert( NULL != pScene );
DefaultLogger::get()->debug("CalcTangentsProcess begin");
bool bHas = false;
for ( unsigned int a = 0; a < pScene->mNumMeshes; a++ ) {
if(ProcessMesh( pScene->mMeshes[a],a))bHas = true;
}
if ( bHas ) {
DefaultLogger::get()->info("CalcTangentsProcess finished. Tangents have been calculated");
} else {
DefaultLogger::get()->debug("CalcTangentsProcess finished");
}
}
// ------------------------------------------------------------------------------------------------
// Calculates tangents and bi-tangents for the given mesh
bool CalcTangentsProcess::ProcessMesh( aiMesh* pMesh, unsigned int meshIndex)
{
// we assume that the mesh is still in the verbose vertex format where each face has its own set
// of vertices and no vertices are shared between faces. Sadly I don't know any quick test to
// assert() it here.
// assert( must be verbose, dammit);
if (pMesh->mTangents) // this implies that mBitangents is also there
return false;
// If the mesh consists of lines and/or points but not of
// triangles or higher-order polygons the normal vectors
// are undefined.
if (!(pMesh->mPrimitiveTypes & (aiPrimitiveType_TRIANGLE | aiPrimitiveType_POLYGON)))
{
DefaultLogger::get()->info("Tangents are undefined for line and point meshes");
return false;
}
// what we can check, though, is if the mesh has normals and texture coordinates. That's a requirement
if( pMesh->mNormals == NULL)
{
DefaultLogger::get()->error("Failed to compute tangents; need normals");
return false;
}
if( configSourceUV >= AI_MAX_NUMBER_OF_TEXTURECOORDS || !pMesh->mTextureCoords[configSourceUV] )
{
DefaultLogger::get()->error((Formatter::format("Failed to compute tangents; need UV data in channel"),configSourceUV));
return false;
}
const float angleEpsilon = 0.9999f;
std::vector<bool> vertexDone( pMesh->mNumVertices, false);
const float qnan = get_qnan();
// create space for the tangents and bitangents
pMesh->mTangents = new aiVector3D[pMesh->mNumVertices];
pMesh->mBitangents = new aiVector3D[pMesh->mNumVertices];
const aiVector3D* meshPos = pMesh->mVertices;
const aiVector3D* meshNorm = pMesh->mNormals;
const aiVector3D* meshTex = pMesh->mTextureCoords[configSourceUV];
aiVector3D* meshTang = pMesh->mTangents;
aiVector3D* meshBitang = pMesh->mBitangents;
// calculate the tangent and bitangent for every face
for( unsigned int a = 0; a < pMesh->mNumFaces; a++)
{
const aiFace& face = pMesh->mFaces[a];
if (face.mNumIndices < 3)
{
// There are less than three indices, thus the tangent vector
// is not defined. We are finished with these vertices now,
// their tangent vectors are set to qnan.
for (unsigned int i = 0; i < face.mNumIndices;++i)
{
unsigned int idx = face.mIndices[i];
vertexDone [idx] = true;
meshTang [idx] = aiVector3D(qnan);
meshBitang [idx] = aiVector3D(qnan);
}
continue;
}
// triangle or polygon... we always use only the first three indices. A polygon
// is supposed to be planar anyways....
// FIXME: (thom) create correct calculation for multi-vertex polygons maybe?
const unsigned int p0 = face.mIndices[0], p1 = face.mIndices[1], p2 = face.mIndices[2];
// position differences p1->p2 and p1->p3
aiVector3D v = meshPos[p1] - meshPos[p0], w = meshPos[p2] - meshPos[p0];
// texture offset p1->p2 and p1->p3
float sx = meshTex[p1].x - meshTex[p0].x, sy = meshTex[p1].y - meshTex[p0].y;
float tx = meshTex[p2].x - meshTex[p0].x, ty = meshTex[p2].y - meshTex[p0].y;
float dirCorrection = (tx * sy - ty * sx) < 0.0f ? -1.0f : 1.0f;
// when t1, t2, t3 in same position in UV space, just use default UV direction.
if ( 0 == sx && 0 ==sy && 0 == tx && 0 == ty ) {
sx = 0.0; sy = 1.0;
tx = 1.0; ty = 0.0;
}
// tangent points in the direction where to positive X axis of the texture coord's would point in model space
// bitangent's points along the positive Y axis of the texture coord's, respectively
aiVector3D tangent, bitangent;
tangent.x = (w.x * sy - v.x * ty) * dirCorrection;
tangent.y = (w.y * sy - v.y * ty) * dirCorrection;
tangent.z = (w.z * sy - v.z * ty) * dirCorrection;
bitangent.x = (w.x * sx - v.x * tx) * dirCorrection;
bitangent.y = (w.y * sx - v.y * tx) * dirCorrection;
bitangent.z = (w.z * sx - v.z * tx) * dirCorrection;
// store for every vertex of that face
for( unsigned int b = 0; b < face.mNumIndices; ++b ) {
unsigned int p = face.mIndices[b];
// project tangent and bitangent into the plane formed by the vertex' normal
aiVector3D localTangent = tangent - meshNorm[p] * (tangent * meshNorm[p]);
aiVector3D localBitangent = bitangent - meshNorm[p] * (bitangent * meshNorm[p]);
localTangent.Normalize(); localBitangent.Normalize();
// reconstruct tangent/bitangent according to normal and bitangent/tangent when it's infinite or NaN.
bool invalid_tangent = is_special_float(localTangent.x) || is_special_float(localTangent.y) || is_special_float(localTangent.z);
bool invalid_bitangent = is_special_float(localBitangent.x) || is_special_float(localBitangent.y) || is_special_float(localBitangent.z);
if (invalid_tangent != invalid_bitangent) {
if (invalid_tangent) {
localTangent = meshNorm[p] ^ localBitangent;
localTangent.Normalize();
} else {
localBitangent = localTangent ^ meshNorm[p];
localBitangent.Normalize();
}
}
// and write it into the mesh.
meshTang[ p ] = localTangent;
meshBitang[ p ] = localBitangent;
}
}
// create a helper to quickly find locally close vertices among the vertex array
// FIX: check whether we can reuse the SpatialSort of a previous step
SpatialSort* vertexFinder = NULL;
SpatialSort _vertexFinder;
float posEpsilon;
if (shared)
{
std::vector<std::pair<SpatialSort,float> >* avf;
shared->GetProperty(AI_SPP_SPATIAL_SORT,avf);
if (avf)
{
std::pair<SpatialSort,float>& blubb = avf->operator [] (meshIndex);
vertexFinder = &blubb.first;
posEpsilon = blubb.second;;
}
}
if (!vertexFinder)
{
_vertexFinder.Fill(pMesh->mVertices, pMesh->mNumVertices, sizeof( aiVector3D));
vertexFinder = &_vertexFinder;
posEpsilon = ComputePositionEpsilon(pMesh);
}
std::vector<unsigned int> verticesFound;
const float fLimit = std::cos(configMaxAngle);
std::vector<unsigned int> closeVertices;
// in the second pass we now smooth out all tangents and bitangents at the same local position
// if they are not too far off.
for( unsigned int a = 0; a < pMesh->mNumVertices; a++)
{
if( vertexDone[a])
continue;
const aiVector3D& origPos = pMesh->mVertices[a];
const aiVector3D& origNorm = pMesh->mNormals[a];
const aiVector3D& origTang = pMesh->mTangents[a];
const aiVector3D& origBitang = pMesh->mBitangents[a];
closeVertices.resize( 0 );
// find all vertices close to that position
vertexFinder->FindPositions( origPos, posEpsilon, verticesFound);
closeVertices.reserve (verticesFound.size()+5);
closeVertices.push_back( a);
// look among them for other vertices sharing the same normal and a close-enough tangent/bitangent
for( unsigned int b = 0; b < verticesFound.size(); b++)
{
unsigned int idx = verticesFound[b];
if( vertexDone[idx])
continue;
if( meshNorm[idx] * origNorm < angleEpsilon)
continue;
if( meshTang[idx] * origTang < fLimit)
continue;
if( meshBitang[idx] * origBitang < fLimit)
continue;
// it's similar enough -> add it to the smoothing group
closeVertices.push_back( idx);
vertexDone[idx] = true;
}
// smooth the tangents and bitangents of all vertices that were found to be close enough
aiVector3D smoothTangent( 0, 0, 0), smoothBitangent( 0, 0, 0);
for( unsigned int b = 0; b < closeVertices.size(); ++b)
{
smoothTangent += meshTang[ closeVertices[b] ];
smoothBitangent += meshBitang[ closeVertices[b] ];
}
smoothTangent.Normalize();
smoothBitangent.Normalize();
// and write it back into all affected tangents
for( unsigned int b = 0; b < closeVertices.size(); ++b)
{
meshTang[ closeVertices[b] ] = smoothTangent;
meshBitang[ closeVertices[b] ] = smoothBitangent;
}
}
return true;
}