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Optimize FindDegenerates so it doesn't explode

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This commit is contained in:
Malcolm Tyrrell
2020-11-02 14:43:35 +00:00
parent de610b8ce9
commit 3deae8760c
2 changed files with 94 additions and 34 deletions
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69
code/PostProcessing/FindDegenerates.cpp
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@@ -52,12 +52,12 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "FindDegenerates.h"
#include <assimp/Exceptional.h>
#include <unordered_map>
using namespace Assimp;
//remove mesh at position 'index' from the scene
static void removeMesh(aiScene* pScene, unsigned const index);
//correct node indices to meshes and remove references to deleted mesh
static void updateSceneGraph(aiNode* pNode, unsigned const index);
static void updateSceneGraph(aiNode* pNode, const std::unordered_map<unsigned int, unsigned int>& meshMap);
// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
@@ -91,50 +91,51 @@ void FindDegeneratesProcess::SetupProperties(const Importer* pImp) {
// Executes the post processing step on the given imported data.
void FindDegeneratesProcess::Execute( aiScene* pScene) {
ASSIMP_LOG_DEBUG("FindDegeneratesProcess begin");
std::unordered_map<unsigned int, unsigned int> meshMap;
meshMap.reserve(pScene->mNumMeshes);
const unsigned int originalNumMeshes = pScene->mNumMeshes;
unsigned int targetIndex = 0;
for (unsigned int i = 0; i < pScene->mNumMeshes;++i)
{
//Do not process point cloud, ExecuteOnMesh works only with faces data
// Do not process point cloud, ExecuteOnMesh works only with faces data
if ((pScene->mMeshes[i]->mPrimitiveTypes != aiPrimitiveType::aiPrimitiveType_POINT) && ExecuteOnMesh(pScene->mMeshes[i])) {
removeMesh(pScene, i);
--i; //the current i is removed, do not skip the next one
delete pScene->mMeshes[i];
// Not strictly required, but clean:
pScene->mMeshes[i] = nullptr;
}
else {
meshMap[i] = targetIndex;
pScene->mMeshes[targetIndex] = pScene->mMeshes[i];
++targetIndex;
}
}
pScene->mNumMeshes = targetIndex;
if (meshMap.size() < originalNumMeshes)
{
updateSceneGraph(pScene->mRootNode, meshMap);
}
ASSIMP_LOG_DEBUG("FindDegeneratesProcess finished");
}
static void removeMesh(aiScene* pScene, unsigned const index) {
//we start at index and copy the pointers one position forward
//save the mesh pointer to delete it later
auto delete_me = pScene->mMeshes[index];
for (unsigned i = index; i < pScene->mNumMeshes - 1; ++i) {
pScene->mMeshes[i] = pScene->mMeshes[i+1];
}
pScene->mMeshes[pScene->mNumMeshes - 1] = nullptr;
--(pScene->mNumMeshes);
delete delete_me;
//removing a mesh also requires updating all references to it in the scene graph
updateSceneGraph(pScene->mRootNode, index);
}
static void updateSceneGraph(aiNode* pNode, unsigned const index) {
static void updateSceneGraph(aiNode* pNode, const std::unordered_map<unsigned int, unsigned int>& meshMap) {
unsigned int targetIndex = 0;
for (unsigned i = 0; i < pNode->mNumMeshes; ++i) {
if (pNode->mMeshes[i] > index) {
--(pNode->mMeshes[i]);
continue;
}
if (pNode->mMeshes[i] == index) {
for (unsigned j = i; j < pNode->mNumMeshes -1; ++j) {
pNode->mMeshes[j] = pNode->mMeshes[j+1];
}
--(pNode->mNumMeshes);
--i;
continue;
const unsigned int sourceMeshIndex = pNode->mMeshes[i];
auto it = meshMap.find(sourceMeshIndex);
if (it != meshMap.end())
{
pNode->mMeshes[targetIndex] = it->second;
++targetIndex;
}
}
pNode->mNumMeshes = targetIndex;
//recurse to all children
for (unsigned i = 0; i < pNode->mNumChildren; ++i) {
updateSceneGraph(pNode->mChildren[i], index);
updateSceneGraph(pNode->mChildren[i], meshMap);
}
}