assimp/code/PostProcessing/JoinVerticesProcess.cpp

420 lines
16 KiB
C++

/*
---------------------------------------------------------------------------
Open Asset Import Library (assimp)
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*/
/** @file Implementation of the post processing step to join identical vertices
* for all imported meshes
*/
#ifndef ASSIMP_BUILD_NO_JOINVERTICES_PROCESS
#include "JoinVerticesProcess.h"
#include "ProcessHelper.h"
#include <assimp/Vertex.h>
#include <assimp/TinyFormatter.h>
#include <stdio.h>
#include <unordered_set>
#include <unordered_map>
#include <memory>
using namespace Assimp;
// ------------------------------------------------------------------------------------------------
// 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) {
ASSIMP_LOG_DEBUG("JoinVerticesProcess begin");
// get the total number of vertices BEFORE the step is executed
int iNumOldVertices = 0;
if (!DefaultLogger::isNullLogger()) {
for( unsigned int a = 0; a < pScene->mNumMeshes; a++) {
iNumOldVertices += pScene->mMeshes[a]->mNumVertices;
}
}
// execute the step
int iNumVertices = 0;
for( unsigned int a = 0; a < pScene->mNumMeshes; a++) {
iNumVertices += ProcessMesh( pScene->mMeshes[a],a);
}
pScene->mFlags |= AI_SCENE_FLAGS_NON_VERBOSE_FORMAT;
// if logging is active, print detailed statistics
if (!DefaultLogger::isNullLogger()) {
if (iNumOldVertices == iNumVertices) {
ASSIMP_LOG_DEBUG("JoinVerticesProcess finished ");
return;
}
// Show statistics
ASSIMP_LOG_INFO("JoinVerticesProcess finished | Verts in: ", iNumOldVertices,
" out: ", iNumVertices, " | ~",
((iNumOldVertices - iNumVertices) / (float)iNumOldVertices) * 100.f );
}
}
namespace {
bool areVerticesEqual(
const Vertex &lhs,
const Vertex &rhs,
unsigned numUVChannels,
unsigned numColorChannels) {
// A little helper to find locally close vertices faster.
// Try to reuse the lookup table from the last step.
const static float epsilon = 1e-5f;
// Squared because we check against squared length of the vector difference
static const float squareEpsilon = epsilon * epsilon;
// Square compare is useful for animeshes vertices compare
if ((lhs.position - rhs.position).SquareLength() > squareEpsilon) {
return false;
}
// 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 comparison succeeds.
// By this method the non-present attributes are effectively ignored in the comparison.
if ((lhs.normal - rhs.normal).SquareLength() > squareEpsilon) {
return false;
}
if ((lhs.tangent - rhs.tangent).SquareLength() > squareEpsilon) {
return false;
}
if ((lhs.bitangent - rhs.bitangent).SquareLength() > squareEpsilon) {
return false;
}
for (unsigned i = 0; i < numUVChannels; i++) {
if ((lhs.texcoords[i] - rhs.texcoords[i]).SquareLength() > squareEpsilon) {
return false;
}
}
for (unsigned i = 0; i < numColorChannels; i++) {
if (GetColorDifference(lhs.colors[i], rhs.colors[i]) > squareEpsilon) {
return false;
}
}
return true;
}
template<class XMesh>
void updateXMeshVertices(XMesh *pMesh, std::vector<int> &uniqueVertices) {
// replace vertex data with the unique data sets
pMesh->mNumVertices = (unsigned int)uniqueVertices.size();
// ----------------------------------------------------------------------------
// NOTE - we're *not* calling Vertex::SortBack() because it would check for
// presence of every single vertex component once PER VERTEX. And our CPU
// dislikes branches, even if they're easily predictable.
// ----------------------------------------------------------------------------
// Position, if present (check made for aiAnimMesh)
if (pMesh->mVertices) {
std::unique_ptr<aiVector3D[]> oldVertices(pMesh->mVertices);
pMesh->mVertices = new aiVector3D[pMesh->mNumVertices];
for (unsigned int a = 0; a < pMesh->mNumVertices; a++)
pMesh->mVertices[a] = oldVertices[uniqueVertices[a]];
}
// Normals, if present
if (pMesh->mNormals) {
std::unique_ptr<aiVector3D[]> oldNormals(pMesh->mNormals);
pMesh->mNormals = new aiVector3D[pMesh->mNumVertices];
for (unsigned int a = 0; a < pMesh->mNumVertices; a++)
pMesh->mNormals[a] = oldNormals[uniqueVertices[a]];
}
// Tangents, if present
if (pMesh->mTangents) {
std::unique_ptr<aiVector3D[]> oldTangents(pMesh->mTangents);
pMesh->mTangents = new aiVector3D[pMesh->mNumVertices];
for (unsigned int a = 0; a < pMesh->mNumVertices; a++)
pMesh->mTangents[a] = oldTangents[uniqueVertices[a]];
}
// Bitangents as well
if (pMesh->mBitangents) {
std::unique_ptr<aiVector3D[]> oldBitangents(pMesh->mBitangents);
pMesh->mBitangents = new aiVector3D[pMesh->mNumVertices];
for (unsigned int a = 0; a < pMesh->mNumVertices; a++)
pMesh->mBitangents[a] = oldBitangents[uniqueVertices[a]];
}
// Vertex colors
for (unsigned int a = 0; pMesh->HasVertexColors(a); a++) {
std::unique_ptr<aiColor4D[]> oldColors(pMesh->mColors[a]);
pMesh->mColors[a] = new aiColor4D[pMesh->mNumVertices];
for (unsigned int b = 0; b < pMesh->mNumVertices; b++)
pMesh->mColors[a][b] = oldColors[uniqueVertices[b]];
}
// Texture coords
for (unsigned int a = 0; pMesh->HasTextureCoords(a); a++) {
std::unique_ptr<aiVector3D[]> oldTextureCoords(pMesh->mTextureCoords[a]);
pMesh->mTextureCoords[a] = new aiVector3D[pMesh->mNumVertices];
for (unsigned int b = 0; b < pMesh->mNumVertices; b++)
pMesh->mTextureCoords[a][b] = oldTextureCoords[uniqueVertices[b]];
}
}
} // namespace
// ------------------------------------------------------------------------------------------------
// Unites identical vertices in the given mesh
// combine hashes
inline void hash_combine(std::size_t &) {
// empty
}
template <typename T, typename... Rest>
inline void hash_combine(std::size_t& seed, const T& v, Rest... rest) {
std::hash<T> hasher;
seed ^= hasher(v) + 0x9e3779b9 + (seed<<6) + (seed>>2);
hash_combine(seed, rest...);
}
//template specialization for std::hash for Vertex
template<>
struct std::hash<Vertex> {
std::size_t operator()(Vertex const& v) const noexcept {
size_t seed = 0;
hash_combine(seed, v.position.x ,v.position.y,v.position.z);
return seed;
}
};
//template specialization for std::equal_to for Vertex
template<>
struct std::equal_to<Vertex> {
equal_to(unsigned numUVChannels, unsigned numColorChannels) :
mNumUVChannels(numUVChannels),
mNumColorChannels(numColorChannels) {}
bool operator()(const Vertex &lhs, const Vertex &rhs) const {
return areVerticesEqual(lhs, rhs, mNumUVChannels, mNumColorChannels);
}
private:
unsigned mNumUVChannels;
unsigned mNumColorChannels;
};
static constexpr size_t JOINED_VERTICES_MARK = 0x80000000u;
// now start the JoinVerticesProcess
int JoinVerticesProcess::ProcessMesh( aiMesh* pMesh, unsigned int meshIndex) {
static_assert( AI_MAX_NUMBER_OF_COLOR_SETS == 8, "AI_MAX_NUMBER_OF_COLOR_SETS == 8");
static_assert( AI_MAX_NUMBER_OF_TEXTURECOORDS == 8, "AI_MAX_NUMBER_OF_TEXTURECOORDS == 8");
// Return early if we don't have any positions
if (!pMesh->HasPositions() || !pMesh->HasFaces()) {
return 0;
}
// We should care only about used vertices, not all of them
// (this can happen due to original file vertices buffer being used by
// multiple meshes)
std::vector<bool> usedVertexIndicesMask;
usedVertexIndicesMask.resize(pMesh->mNumVertices, false);
for (unsigned int a = 0; a < pMesh->mNumFaces; a++) {
aiFace& face = pMesh->mFaces[a];
for (unsigned int b = 0; b < face.mNumIndices; b++) {
usedVertexIndicesMask[face.mIndices[b]] = true;
}
}
// We'll never have more vertices afterwards.
std::vector<int> uniqueVertices;
uniqueVertices.reserve( pMesh->mNumVertices);
// For each vertex the index of the vertex it was replaced by.
// Since the maximal number of vertices is 2^31-1, the most significand bit can be used to mark
// whether a new vertex was created for the index (true) or if it was replaced by an existing
// unique vertex (false). This saves an additional std::vector<bool> and greatly enhances
// branching performance.
static_assert(AI_MAX_VERTICES == 0x7fffffff, "AI_MAX_VERTICES == 0x7fffffff");
std::vector<unsigned int> replaceIndex( pMesh->mNumVertices, 0xffffffff);
// float posEpsilonSqr;
SpatialSort *vertexFinder = nullptr;
SpatialSort _vertexFinder;
typedef std::pair<SpatialSort,float> SpatPair;
if (shared) {
std::vector<SpatPair >* avf;
shared->GetProperty(AI_SPP_SPATIAL_SORT,avf);
if (avf) {
SpatPair& blubb = (*avf)[meshIndex];
vertexFinder = &blubb.first;
// posEpsilonSqr = blubb.second;
}
}
if (!vertexFinder) {
// bad, need to compute it.
_vertexFinder.Fill(pMesh->mVertices, pMesh->mNumVertices, sizeof( aiVector3D));
vertexFinder = &_vertexFinder;
// posEpsilonSqr = ComputePositionEpsilon(pMesh);
}
// Again, better waste some bytes than a realloc ...
std::vector<unsigned int> verticesFound;
verticesFound.reserve(10);
// Run an optimized code path if we don't have multiple UVs or vertex colors.
// This should yield false in more than 99% of all imports ...
const bool hasAnimMeshes = pMesh->mNumAnimMeshes > 0;
// We'll never have more vertices afterwards.
std::vector<std::vector<int>> uniqueAnimatedVertices;
if (hasAnimMeshes) {
uniqueAnimatedVertices.resize(pMesh->mNumAnimMeshes);
for (unsigned int animMeshIndex = 0; animMeshIndex < pMesh->mNumAnimMeshes; animMeshIndex++) {
uniqueAnimatedVertices[animMeshIndex].reserve(pMesh->mNumVertices);
}
}
// a map that maps a vertex to its new index
const auto numBuckets = pMesh->mNumVertices;
const auto hasher = std::hash<Vertex>();
const auto comparator = std::equal_to<Vertex>(
pMesh->GetNumUVChannels(),
pMesh->GetNumColorChannels());
std::unordered_map<Vertex, int> vertex2Index(numBuckets, hasher, comparator);
// we can not end up with more vertices than we started with
vertex2Index.reserve(pMesh->mNumVertices);
// Now check each vertex if it brings something new to the table
int newIndex = 0;
for( unsigned int a = 0; a < pMesh->mNumVertices; a++) {
// if the vertex is unused Do nothing
if (!usedVertexIndicesMask[a]) {
continue;
}
// collect the vertex data
Vertex v(pMesh,a);
// is the vertex already in the map?
auto it = vertex2Index.find(v);
// if the vertex is not in the map then it is a new vertex add it.
if (it == vertex2Index.end()) {
// this is a new vertex give it a new index
vertex2Index[v] = newIndex;
//keep track of its index and increment 1
replaceIndex[a] = newIndex++;
// add the vertex to the unique vertices
uniqueVertices.push_back(a);
if (hasAnimMeshes) {
for (unsigned int animMeshIndex = 0; animMeshIndex < pMesh->mNumAnimMeshes; animMeshIndex++) {
uniqueAnimatedVertices[animMeshIndex].emplace_back(a);
}
}
} else{
// if the vertex is already there just find the replace index that is appropriate to it
// mark it with JOINED_VERTICES_MARK
replaceIndex[a] = it->second | JOINED_VERTICES_MARK;
}
}
if (!DefaultLogger::isNullLogger() && DefaultLogger::get()->getLogSeverity() == Logger::VERBOSE) {
ASSIMP_LOG_VERBOSE_DEBUG(
"Mesh ",meshIndex,
" (",
(pMesh->mName.length ? pMesh->mName.data : "unnamed"),
") | Verts in: ",pMesh->mNumVertices,
" out: ",
uniqueVertices.size(),
" | ~",
((pMesh->mNumVertices - uniqueVertices.size()) / (float)pMesh->mNumVertices) * 100.f,
"%"
);
}
updateXMeshVertices(pMesh, uniqueVertices);
if (hasAnimMeshes) {
for (unsigned int animMeshIndex = 0; animMeshIndex < pMesh->mNumAnimMeshes; animMeshIndex++) {
updateXMeshVertices(pMesh->mAnimMeshes[animMeshIndex], uniqueAnimatedVertices[animMeshIndex]);
}
}
// 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++) {
face.mIndices[b] = replaceIndex[face.mIndices[b]] & ~JOINED_VERTICES_MARK;
}
}
// adjust bone vertex weights.
for( int a = 0; a < (int)pMesh->mNumBones; a++) {
aiBone* bone = pMesh->mBones[a];
std::vector<aiVertexWeight> newWeights;
newWeights.reserve( bone->mNumWeights);
if (nullptr != bone->mWeights) {
for ( unsigned int b = 0; b < bone->mNumWeights; b++ ) {
const aiVertexWeight& ow = bone->mWeights[ b ];
// if the vertex is a unique one, translate it
// filter out joined vertices by JOINED_VERTICES_MARK.
if ( !( replaceIndex[ ow.mVertexId ] & JOINED_VERTICES_MARK ) ) {
aiVertexWeight nw;
nw.mVertexId = replaceIndex[ ow.mVertexId ];
nw.mWeight = ow.mWeight;
newWeights.push_back( nw );
}
}
} else {
ASSIMP_LOG_ERROR( "X-Export: aiBone shall contain weights, but pointer to them is nullptr." );
}
if (newWeights.size() > 0) {
// kill the old and replace them with the translated weights
delete [] bone->mWeights;
bone->mNumWeights = (unsigned int)newWeights.size();
bone->mWeights = new aiVertexWeight[bone->mNumWeights];
memcpy( bone->mWeights, &newWeights[0], bone->mNumWeights * sizeof( aiVertexWeight));
}
}
return pMesh->mNumVertices;
}
#endif // !! ASSIMP_BUILD_NO_JOINVERTICES_PROCESS