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trimesh_remove.cc

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/*
Szymon Rusinkiewicz
Stanford Graphics Lab

trimesh_remove.cc
Removing sets of vertices or faces from trimeshes.
*/

#include <stdio.h>
#include "triutil.h"
#include "trimesh.h"
#include <vector>
using std::vector;

namespace trimesh {

// Remove the indicated vertices from the TriMesh.
//
// Faces are renumbered to reflect the new numbering of vertices, and any
// faces that included a vertex to be removed will also be removed.
//
// Any per-vertex properties are renumbered along with the vertices.
// Any triangle strips, neighbor lists, or adjacency lists are deleted.
// Note that memory for vertices and properties is not reallocated.
void TriMesh::RemoveVertices(const vector<bool> &toremove)
{
        // Build a table that tells how the vertices will be remapped
        if (!numvertices)
                return;
        printf("Removing vertices... "); fflush(stdout);
        vector<int> remap_table(numvertices);
        int next=0;
        for (int i=0; i < numvertices; i++) {
                if (toremove[i])
                        remap_table[i] = -1;
                else
                        remap_table[i] = next++;
        }

        // Nothing to delete?
        if (next == numvertices) {
                printf("None removed.\n");
                return;
        }

        // Remap the vertices and per-vertex properties
        for (int i=0; i < numvertices; i++) {
                if (remap_table[i] == -1)  continue;
                vertices[remap_table[i]][0] = vertices[i][0];
                vertices[remap_table[i]][1] = vertices[i][1];
                vertices[remap_table[i]][2] = vertices[i][2];
                if (normals) {
                        normals[remap_table[i]][0] = normals[i][0];
                        normals[remap_table[i]][1] = normals[i][1];
                        normals[remap_table[i]][2] = normals[i][2];
                }
                if (colors) {
                        colors[remap_table[i]][0] = colors[i][0];
                        colors[remap_table[i]][1] = colors[i][1];
                        colors[remap_table[i]][2] = colors[i][2];
                }
                if (confidences)
                        confidences[remap_table[i]] = confidences[i];
        }
        printf("%d vertices removed... Done.\n", numvertices - next);
        numvertices = next;

        // Nuke neighbor and adjacency lists
        free_adjacentfaces();
        free_neighbors();

        // Renumber faces
        need_faces();
        free_tstrips();
        int nextface=0;
        for (int i=0; i < numfaces; i++) {
                int n0 = (faces[nextface][0] = remap_table[faces[i][0]]);
                int n1 = (faces[nextface][1] = remap_table[faces[i][1]]);
                int n2 = (faces[nextface][2] = remap_table[faces[i][2]]);
                if ((n0 != -1) && (n1 != -1) && (n2 != -1))
                        nextface++;
        }
        numfaces = nextface;
}


// Remove vertices that aren't referenced by any face
void TriMesh::RemoveUnusedVertices()
{
        if (!numvertices)
                return;
        need_faces();
        vector<bool> unused(numvertices, true);
        for (int i=0; i < numfaces; i++)
                unused[faces[i][0]] = unused[faces[i][1]] =
                        unused[faces[i][2]] = false;
        RemoveVertices(unused);
}


// Remove faces as indicated by toremove.  Should probably be
// followed by a call to RemoveUnusedVertices()
void TriMesh::RemoveFaces(const vector<bool> &toremove)
{
        need_faces();
        free_tstrips();
        if (!numfaces)
                return;
        printf("Removing faces... "); fflush(stdout);

        int next=0;
        for (int i=0; i < numfaces; i++) {
                if (toremove[i])
                        continue;
                faces[next][0] = faces[i][0];
                faces[next][1] = faces[i][1];
                faces[next][2] = faces[i][2];
                next++;
        }
        if (next == numfaces) {
                printf("None removed.\n");
                return;
        }

        printf("%d faces removed... Done.\n", numfaces - next);
        numfaces = next;
}

} // namespace trimesh

---

trimesh
Author(s): Benjamin Pitzer
autogenerated on Mon Mar 4 11:05:50 2013