assimp/code/JoinVerticesProcess.cpp

263 lines
9.7 KiB
C++

/** @file Implementation of the post processing step to join identical vertices
* for all imported meshes
*/
#include <vector>
#include <assert.h>
#include "JoinVerticesProcess.h"
#include "SpatialSort.h"
#include "../include/aiPostProcess.h"
#include "../include/aiMesh.h"
#include "../include/aiScene.h"
using namespace Assimp;
// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
JoinVerticesProcess::JoinVerticesProcess()
{
// nothing to do here
}
// ------------------------------------------------------------------------------------------------
// Destructor, private as well
JoinVerticesProcess::~JoinVerticesProcess()
{
// nothing to do here
}
// ------------------------------------------------------------------------------------------------
// Returns whether the processing step is present in the given flag field.
bool JoinVerticesProcess::IsActive( unsigned int pFlags) const
{
return (pFlags & aiProcess_JoinIdenticalVertices) != 0;
}
// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void JoinVerticesProcess::Execute( aiScene* pScene)
{
for( unsigned int a = 0; a < pScene->mNumMeshes; a++)
ProcessMesh( pScene->mMeshes[a]);
}
// ------------------------------------------------------------------------------------------------
// Unites identical vertices in the given mesh
void JoinVerticesProcess::ProcessMesh( aiMesh* pMesh)
{
// helper structure to hold all the data a single vertex can possibly have
typedef struct Vertex vertex;
struct Vertex
{
aiVector3D mPosition;
aiVector3D mNormal;
aiVector3D mTangent, mBitangent;
aiColor4D mColors[AI_MAX_NUMBER_OF_COLOR_SETS];
aiVector3D mTexCoords[AI_MAX_NUMBER_OF_TEXTURECOORDS];
};
std::vector<Vertex> uniqueVertices;
uniqueVertices.reserve( pMesh->mNumVertices);
// For each vertex the index of the vertex it was replaced by.
std::vector<unsigned int> replaceIndex( pMesh->mNumVertices, 0xffffffff);
// for each vertex whether it was replaced by an existing unique vertex (true) or a new vertex was created for it (false)
std::vector<bool> isVertexUnique( pMesh->mNumVertices, false);
// calculate the position bounds so we have a reliable epsilon to check position differences against
aiVector3D minVec( 1e10f, 1e10f, 1e10f), maxVec( -1e10f, -1e10f, -1e10f);
for( unsigned int a = 0; a < pMesh->mNumVertices; a++)
{
minVec.x = std::min( minVec.x, pMesh->mVertices[a].x);
minVec.y = std::min( minVec.y, pMesh->mVertices[a].y);
minVec.z = std::min( minVec.z, pMesh->mVertices[a].z);
maxVec.x = std::max( maxVec.x, pMesh->mVertices[a].x);
maxVec.y = std::max( maxVec.y, pMesh->mVertices[a].y);
maxVec.z = std::max( maxVec.z, pMesh->mVertices[a].z);
}
// squared because we check against squared length of the vector difference
const float epsilon = 1e-5f;
const float posEpsilon = (maxVec - minVec).Length() * epsilon;
const float squareEpsilon = epsilon * epsilon;
// a little helper to find locally close vertices faster
SpatialSort vertexFinder( pMesh->mVertices, pMesh->mNumVertices, sizeof( aiVector3D));
std::vector<unsigned int> verticesFound;
// now check each vertex if it brings something new to the table
for( unsigned int a = 0; a < pMesh->mNumVertices; a++)
{
// collect the vertex data
Vertex v;
v.mPosition = pMesh->mVertices[a];
v.mNormal = (pMesh->mNormals != NULL) ? pMesh->mNormals[a] : aiVector3D( 0, 0, 0);
v.mTangent = (pMesh->mTangents != NULL) ? pMesh->mTangents[a] : aiVector3D( 0, 0, 0);
v.mBitangent = (pMesh->mBitangents != NULL) ? pMesh->mBitangents[a] : aiVector3D( 0, 0, 0);
for( unsigned int b = 0; b < AI_MAX_NUMBER_OF_COLOR_SETS; b++)
v.mColors[b] = (pMesh->mColors[b] != NULL) ? pMesh->mColors[b][a] : aiColor4D( 0, 0, 0, 0);
for( unsigned int b = 0; b < AI_MAX_NUMBER_OF_TEXTURECOORDS; b++)
v.mTexCoords[b] = (pMesh->mTextureCoords[b] != NULL) ? pMesh->mTextureCoords[b][a] : aiVector3D( 0, 0, 0);
// collect all vertices that are close enough to the given position
vertexFinder.FindPositions( v.mPosition, posEpsilon, verticesFound);
unsigned int matchIndex = 0xffffffff;
// check all unique vertices close to the position if this vertex is already present among them
for( unsigned int b = 0; b < verticesFound.size(); b++)
{
unsigned int vidx = verticesFound[b];
unsigned int uidx = replaceIndex[ vidx];
if( uidx == 0xffffffff || !isVertexUnique[ vidx])
continue;
const Vertex& uv = uniqueVertices[ uidx];
// Position mismatch is impossible - the vertex finder already discarded all non-matching positions
// We just test the other attributes even if they're not present in the mesh.
// In this case they're initialized to 0 so the comparision succeeds.
// By this method the non-present attributes are effectively ignored in the comparision.
if( (uv.mNormal - v.mNormal).SquareLength() > squareEpsilon)
continue;
if( (uv.mTangent - v.mTangent).SquareLength() > squareEpsilon)
continue;
if( (uv.mBitangent - v.mBitangent).SquareLength() > squareEpsilon)
continue;
// manually unrolled because continue wouldn't work as desired in an inner loop
assert( AI_MAX_NUMBER_OF_COLOR_SETS == 4);
if( GetColorDifference( uv.mColors[0], v.mColors[0]) > squareEpsilon)
continue;
if( GetColorDifference( uv.mColors[1], v.mColors[1]) > squareEpsilon)
continue;
if( GetColorDifference( uv.mColors[2], v.mColors[2]) > squareEpsilon)
continue;
if( GetColorDifference( uv.mColors[3], v.mColors[3]) > squareEpsilon)
continue;
// texture coord matching manually unrolled as well
assert( AI_MAX_NUMBER_OF_TEXTURECOORDS == 4);
if( (uv.mTexCoords[0] - v.mTexCoords[0]).SquareLength() > squareEpsilon)
continue;
if( (uv.mTexCoords[1] - v.mTexCoords[1]).SquareLength() > squareEpsilon)
continue;
if( (uv.mTexCoords[2] - v.mTexCoords[2]).SquareLength() > squareEpsilon)
continue;
if( (uv.mTexCoords[3] - v.mTexCoords[3]).SquareLength() > squareEpsilon)
continue;
// we're still here -> this vertex perfectly matches our given vertex
matchIndex = uidx;
break;
}
// found a replacement vertex among the uniques?
if( matchIndex != 0xffffffff)
{
// store where to found the matching unique vertex
replaceIndex[a] = matchIndex;
isVertexUnique[a] = false;
} else
{
// no unique vertex matches it upto now -> so add it
replaceIndex[a] = uniqueVertices.size();
uniqueVertices.push_back( v);
isVertexUnique[a] = true;
}
}
// replace vertex data with the unique data sets
pMesh->mNumVertices = uniqueVertices.size();
// Position
delete [] pMesh->mVertices;
pMesh->mVertices = new aiVector3D[pMesh->mNumVertices];
for( unsigned int a = 0; a < pMesh->mNumVertices; a++)
pMesh->mVertices[a] = uniqueVertices[a].mPosition;
// Normals, if present
if( pMesh->mNormals)
{
delete [] pMesh->mNormals;
pMesh->mNormals = new aiVector3D[pMesh->mNumVertices];
for( unsigned int a = 0; a < pMesh->mNumVertices; a++)
pMesh->mNormals[a] = uniqueVertices[a].mNormal;
}
// Tangents, if present
if( pMesh->mTangents)
{
delete [] pMesh->mTangents;
pMesh->mTangents = new aiVector3D[pMesh->mNumVertices];
for( unsigned int a = 0; a < pMesh->mNumVertices; a++)
pMesh->mTangents[a] = uniqueVertices[a].mTangent;
}
// Bitangents as well
if( pMesh->mBitangents)
{
delete [] pMesh->mBitangents;
pMesh->mBitangents = new aiVector3D[pMesh->mNumVertices];
for( unsigned int a = 0; a < pMesh->mNumVertices; a++)
pMesh->mBitangents[a] = uniqueVertices[a].mBitangent;
}
// Vertex colors
for( unsigned int a = 0; a < AI_MAX_NUMBER_OF_COLOR_SETS; a++)
{
if( !pMesh->mColors[a])
continue;
delete [] pMesh->mColors[a];
pMesh->mColors[a] = new aiColor4D[pMesh->mNumVertices];
for( unsigned int b = 0; b < pMesh->mNumVertices; b++)
pMesh->mColors[a][b] = uniqueVertices[b].mColors[a];
}
// Texture coords
for( unsigned int a = 0; a < AI_MAX_NUMBER_OF_TEXTURECOORDS; a++)
{
if( !pMesh->mTextureCoords[a])
continue;
delete [] pMesh->mTextureCoords[a];
pMesh->mTextureCoords[a] = new aiVector3D[pMesh->mNumVertices];
for( unsigned int b = 0; b < pMesh->mNumVertices; b++)
pMesh->mTextureCoords[a][b] = uniqueVertices[b].mTexCoords[a];
}
// adjust the indices in all faces
for( unsigned int a = 0; a < pMesh->mNumFaces; a++)
{
aiFace& face = pMesh->mFaces[a];
for( unsigned int b = 0; b < face.mNumIndices; b++)
{
const size_t index = face.mIndices[b];
face.mIndices[b] = replaceIndex[face.mIndices[b]];
}
}
// adjust bone vertex weights.
for( unsigned int a = 0; a < pMesh->mNumBones; a++)
{
aiBone* bone = pMesh->mBones[a];
std::vector<aiVertexWeight> newWeights;
newWeights.reserve( bone->mNumWeights);
for( unsigned int b = 0; b < bone->mNumWeights; b++)
{
const aiVertexWeight& ow = bone->mWeights[b];
// if the vertex is a unique one, translate it
if( isVertexUnique[ow.mVertexId])
{
aiVertexWeight nw;
nw.mVertexId = replaceIndex[ow.mVertexId];
nw.mWeight = ow.mWeight;
newWeights.push_back( nw);
}
}
// there should be some. At least I think there should be some
assert( newWeights.size() > 0);
// kill the old and replace them with the translated weights
delete [] bone->mWeights;
bone->mNumWeights = newWeights.size();
bone->mWeights = new aiVertexWeight[bone->mNumWeights];
memcpy( bone->mWeights, &newWeights[0], bone->mNumWeights * sizeof( aiVertexWeight));
}
}