restructure more

ThirdParty/assimp/code/AssetLib/Assjson/mesh_splitter.cpp

@@ -0,0 +1,319 @@
+/*
+Assimp2Json
+Copyright (c) 2011, Alexander C. Gessler
+
+Licensed under a 3-clause BSD license. See the LICENSE file for more information.
+
+*/
+
+#include "mesh_splitter.h"
+
+#include <assimp/scene.h>
+
+// ----------------------------------------------------------------------------
+// Note: this is largely based on assimp's SplitLargeMeshes_Vertex process.
+// it is refactored and the coding style is slightly improved, though.
+// ----------------------------------------------------------------------------
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void MeshSplitter::Execute( aiScene* pScene) {
+	std::vector<std::pair<aiMesh*, unsigned int> > source_mesh_map;
+
+	for( unsigned int a = 0; a < pScene->mNumMeshes; a++) {
+		SplitMesh(a, pScene->mMeshes[a],source_mesh_map);
+	}
+
+	const unsigned int size = static_cast<unsigned int>(source_mesh_map.size());
+	if (size != pScene->mNumMeshes) {
+		// it seems something has been split. rebuild the mesh list
+		delete[] pScene->mMeshes;
+		pScene->mNumMeshes = size;
+		pScene->mMeshes = new aiMesh*[size]();
+
+		for (unsigned int i = 0; i < size;++i) {
+			pScene->mMeshes[i] = source_mesh_map[i].first;
+		}
+
+		// now we need to update all nodes
+		UpdateNode(pScene->mRootNode,source_mesh_map);
+	}
+}
+
+
+// ------------------------------------------------------------------------------------------------
+void MeshSplitter::UpdateNode(aiNode* pcNode, const std::vector<std::pair<aiMesh*, unsigned int> >& source_mesh_map) {
+	// TODO: should better use std::(multi)set for source_mesh_map.
+
+	// for every index in out list build a new entry
+	std::vector<unsigned int> aiEntries;
+	aiEntries.reserve(pcNode->mNumMeshes + 1);
+	for (unsigned int i = 0; i < pcNode->mNumMeshes;++i)	{
+		for (unsigned int a = 0, end = static_cast<unsigned int>(source_mesh_map.size()); a < end;++a)	{
+			if (source_mesh_map[a].second == pcNode->mMeshes[i])	{
+				aiEntries.push_back(a);
+			}
+		}
+	}
+
+	// now build the new list
+	delete pcNode->mMeshes;
+	pcNode->mNumMeshes = static_cast<unsigned int>(aiEntries.size());
+	pcNode->mMeshes = new unsigned int[pcNode->mNumMeshes];
+
+	for (unsigned int b = 0; b < pcNode->mNumMeshes;++b) {
+		pcNode->mMeshes[b] = aiEntries[b];
+	}
+
+	// recursively update children
+	for (unsigned int i = 0, end = pcNode->mNumChildren; i < end;++i)	{
+		UpdateNode ( pcNode->mChildren[i], source_mesh_map );
+	}
+}
+
+static const unsigned int WAS_NOT_COPIED = 0xffffffff;
+
+using PerVertexWeight = std::pair <unsigned int,float>;
+using VertexWeightTable = std::vector	<PerVertexWeight>;
+
+// ------------------------------------------------------------------------------------------------
+VertexWeightTable* ComputeVertexBoneWeightTable(const aiMesh* pMesh) {
+	if (!pMesh || !pMesh->mNumVertices || !pMesh->mNumBones) {
+		return nullptr;
+	}
+
+	VertexWeightTable* const avPerVertexWeights = new VertexWeightTable[pMesh->mNumVertices];
+	for (unsigned int i = 0; i < pMesh->mNumBones;++i)	{
+
+		aiBone* bone = pMesh->mBones[i];
+		for (unsigned int a = 0; a < bone->mNumWeights;++a)	{
+			const aiVertexWeight& weight = bone->mWeights[a];
+			avPerVertexWeights[weight.mVertexId].emplace_back(i,weight.mWeight);
+		}
+	}
+	return avPerVertexWeights;
+}
+
+// ------------------------------------------------------------------------------------------------
+void MeshSplitter :: SplitMesh(unsigned int a, aiMesh* in_mesh, std::vector<std::pair<aiMesh*, unsigned int> >& source_mesh_map) {
+	// TODO: should better use std::(multi)set for source_mesh_map.
+
+	if (in_mesh->mNumVertices <= LIMIT)	{
+		source_mesh_map.emplace_back(in_mesh,a);
+		return;
+	}
+
+	// build a per-vertex weight list if necessary
+	VertexWeightTable* avPerVertexWeights = ComputeVertexBoneWeightTable(in_mesh);
+
+	// we need to split this mesh into sub meshes. Estimate submesh size
+	const unsigned int sub_meshes = (in_mesh->mNumVertices / LIMIT) + 1;
+
+	// create a std::vector<unsigned int> to remember which vertices have already
+	// been copied and to which position (i.e. output index)
+	std::vector<unsigned int> was_copied_to;
+	was_copied_to.resize(in_mesh->mNumVertices,WAS_NOT_COPIED);
+
+	// Try to find a good estimate for the number of output faces
+	// per mesh. Add 12.5% as buffer
+	unsigned int size_estimated = in_mesh->mNumFaces / sub_meshes;
+	size_estimated += size_estimated / 8;
+
+	// now generate all submeshes
+	unsigned int base = 0;
+	while (true) {
+		const unsigned int out_vertex_index = LIMIT;
+
+		aiMesh* out_mesh = new aiMesh();
+		out_mesh->mNumVertices = 0;
+		out_mesh->mMaterialIndex = in_mesh->mMaterialIndex;
+
+		// the name carries the adjacency information between the meshes
+		out_mesh->mName = in_mesh->mName;
+
+		typedef std::vector<aiVertexWeight> BoneWeightList;
+		if (in_mesh->HasBones())	{
+			out_mesh->mBones = new aiBone*[in_mesh->mNumBones]();
+		}
+
+		// clear the temporary helper array
+		if (base)	{
+			std::fill(was_copied_to.begin(), was_copied_to.end(), WAS_NOT_COPIED);
+		}
+
+		std::vector<aiFace> vFaces;
+
+		// reserve enough storage for most cases
+		if (in_mesh->HasPositions()) {
+			out_mesh->mVertices = new aiVector3D[out_vertex_index];
+		}
+
+		if (in_mesh->HasNormals()) {
+			out_mesh->mNormals = new aiVector3D[out_vertex_index];
+		}
+
+		if (in_mesh->HasTangentsAndBitangents())	{
+			out_mesh->mTangents = new aiVector3D[out_vertex_index];
+			out_mesh->mBitangents = new aiVector3D[out_vertex_index];
+		}
+
+		for (unsigned int c = 0; in_mesh->HasVertexColors(c);++c)	{
+			out_mesh->mColors[c] = new aiColor4D[out_vertex_index];
+		}
+
+		for (unsigned int c = 0; in_mesh->HasTextureCoords(c);++c)	{
+			out_mesh->mNumUVComponents[c] = in_mesh->mNumUVComponents[c];
+			out_mesh->mTextureCoords[c] = new aiVector3D[out_vertex_index];
+		}
+		vFaces.reserve(size_estimated);
+
+		// (we will also need to copy the array of indices)
+		while (base < in_mesh->mNumFaces) {
+			const unsigned int iNumIndices = in_mesh->mFaces[base].mNumIndices;
+
+			// doesn't catch degenerates but is quite fast
+			unsigned int iNeed = 0;
+			for (unsigned int v = 0; v < iNumIndices;++v)	{
+				unsigned int index = in_mesh->mFaces[base].mIndices[v];
+
+				// check whether we do already have this vertex
+				if (WAS_NOT_COPIED == was_copied_to[index])	{
+					iNeed++;
+				}
+			}
+			if (out_mesh->mNumVertices + iNeed > out_vertex_index)	{
+				// don't use this face
+				break;
+			}
+
+			vFaces.emplace_back();
+			aiFace& rFace = vFaces.back();
+
+			// setup face type and number of indices
+			rFace.mNumIndices = iNumIndices;
+			rFace.mIndices = new unsigned int[iNumIndices];
+
+			// need to update the output primitive types
+			switch (rFace.mNumIndices)
+			{
+			case 1:
+				out_mesh->mPrimitiveTypes |= aiPrimitiveType_POINT;
+				break;
+			case 2:
+				out_mesh->mPrimitiveTypes |= aiPrimitiveType_LINE;
+				break;
+			case 3:
+				out_mesh->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
+				break;
+			default:
+				out_mesh->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
+			}
+
+			// and copy the contents of the old array, offset them by current base
+			for (unsigned int v = 0; v < iNumIndices;++v) {
+				const unsigned int index = in_mesh->mFaces[base].mIndices[v];
+
+				// check whether we do already have this vertex
+				if (WAS_NOT_COPIED != was_copied_to[index]) {
+					rFace.mIndices[v] = was_copied_to[index];
+					continue;
+				}
+
+				// copy positions
+				out_mesh->mVertices[out_mesh->mNumVertices] = (in_mesh->mVertices[index]);
+
+				// copy normals
+				if (in_mesh->HasNormals()) {
+					out_mesh->mNormals[out_mesh->mNumVertices] = (in_mesh->mNormals[index]);
+				}
+
+				// copy tangents/bi-tangents
+				if (in_mesh->HasTangentsAndBitangents()) {
+					out_mesh->mTangents[out_mesh->mNumVertices] = (in_mesh->mTangents[index]);
+					out_mesh->mBitangents[out_mesh->mNumVertices] = (in_mesh->mBitangents[index]);
+				}
+
+				// texture coordinates
+				for (unsigned int c = 0;  c < AI_MAX_NUMBER_OF_TEXTURECOORDS;++c) {
+					if (in_mesh->HasTextureCoords( c)) {
+						out_mesh->mTextureCoords[c][out_mesh->mNumVertices] = in_mesh->mTextureCoords[c][index];
+					}
+				}
+				// vertex colors
+				for (unsigned int c = 0;  c < AI_MAX_NUMBER_OF_COLOR_SETS;++c) {
+					if (in_mesh->HasVertexColors( c)) {
+						out_mesh->mColors[c][out_mesh->mNumVertices] = in_mesh->mColors[c][index];
+					}
+				}
+				// check whether we have bone weights assigned to this vertex
+				rFace.mIndices[v] = out_mesh->mNumVertices;
+				if (avPerVertexWeights) {
+					VertexWeightTable& table = avPerVertexWeights[ out_mesh->mNumVertices ];
+					for (VertexWeightTable::const_iterator iter = table.begin(), end = table.end(); iter != end;++iter) {
+						// allocate the bone weight array if necessary and store it in the mBones field (HACK!)
+						BoneWeightList* weight_list = reinterpret_cast<BoneWeightList*>(out_mesh->mBones[(*iter).first]);
+						if (!weight_list) {
+							weight_list = new BoneWeightList();
+							out_mesh->mBones[(*iter).first] = reinterpret_cast<aiBone*>(weight_list);
+						}
+						weight_list->push_back(aiVertexWeight(out_mesh->mNumVertices,(*iter).second));
+					}
+				}
+
+				was_copied_to[index] = out_mesh->mNumVertices;
+				out_mesh->mNumVertices++;
+			}
+			base++;
+			if(out_mesh->mNumVertices == out_vertex_index) {
+				// break here. The face is only added if it was complete
+				break;
+			}
+		}
+
+		// check which bones we'll need to create for this submesh
+		if (in_mesh->HasBones()) {
+			aiBone** ppCurrent = out_mesh->mBones;
+			for (unsigned int k = 0; k < in_mesh->mNumBones;++k) {
+				// check whether the bone exists
+				BoneWeightList* const weight_list = reinterpret_cast<BoneWeightList*>(out_mesh->mBones[k]);
+
+				if (weight_list) {
+					const aiBone* const bone_in = in_mesh->mBones[k];
+					aiBone* const bone_out = new aiBone();
+					*ppCurrent++ = bone_out;
+					bone_out->mName = aiString(bone_in->mName);
+					bone_out->mOffsetMatrix =bone_in->mOffsetMatrix;
+					bone_out->mNumWeights = (unsigned int)weight_list->size();
+					bone_out->mWeights = new aiVertexWeight[bone_out->mNumWeights];
+
+					// copy the vertex weights
+					::memcpy(bone_out->mWeights, &(*weight_list)[0],bone_out->mNumWeights * sizeof(aiVertexWeight));
+
+					delete weight_list;
+					out_mesh->mNumBones++;
+				}
+			}
+		}
+
+		// copy the face list to the mesh
+		out_mesh->mFaces = new aiFace[vFaces.size()];
+		out_mesh->mNumFaces = (unsigned int)vFaces.size();
+
+		for (unsigned int p = 0; p < out_mesh->mNumFaces;++p) {
+			out_mesh->mFaces[p] = vFaces[p];
+		}
+
+		// add the newly created mesh to the list
+		source_mesh_map.emplace_back(out_mesh,a);
+
+		if (base == in_mesh->mNumFaces) {
+			break;
+		}
+	}
+
+	// delete the per-vertex weight list again
+	delete[] avPerVertexWeights;
+
+	// now delete the old mesh data
+	delete in_mesh;
+}