#include <QFile>
#include <QDataStream>
+#include <QVector3D>
#include <algorithm>
#include "mesh.h"
-Mesh::Mesh(const Eigen::Matrix3Xf& v, const Eigen::Matrix3Xi& i)
+struct Vec3
+{
+ GLfloat x, y, z;
+ bool operator!=(const Vec3& rhs) const
+ {
+ return x != rhs.x || y != rhs.y || z != rhs.z;
+ }
+ bool operator<(const Vec3& rhs) const
+ {
+ if (x != rhs.x) return x < rhs.x;
+ else if (y != rhs.y) return y < rhs.y;
+ else if (z != rhs.z) return z < rhs.z;
+ else return false;
+ }
+};
+
+
+Mesh::Mesh(std::vector<GLfloat> v, std::vector<GLuint> i)
: vertices(v), indices(i)
{
// Nothing to do here
data.setByteOrder(QDataStream::LittleEndian);
data.setFloatingPointPrecision(QDataStream::SinglePrecision);
+ // Skip .stl file header
data.skipRawData(80);
+
+ // Load the triangle count from the .stl file
uint32_t tri_count;
data >> tri_count;
- // Extract vertices into a vector of Vector4d objects
- std::vector<Eigen::Vector4d> verts(tri_count*3);
- for (unsigned i=0; i < tri_count; ++i)
+ // Extract vertices into an array of xyz, unsigned pairs
+ QVector<std::pair<Vec3, GLuint>> verts(tri_count*3);
+
+ // Store vertices in the array, processing one triangle at a time.
+ for (auto v=verts.begin(); v != verts.end(); v += 3)
{
+ // Skip face's normal vector
data.skipRawData(3*sizeof(float));
- for (int j=0; j < 3; ++j)
- {
- float x, y, z;
- data >> x >> y >> z;
- verts[3*i + j] << x, y, z, 3*i + j;
- }
+
+ // Load vertex data from .stl file into vertices
+ data >> v[0].first.x >> v[0].first.y >> v[0].first.z;
+ data >> v[1].first.x >> v[1].first.y >> v[1].first.z;
+ data >> v[2].first.x >> v[2].first.y >> v[2].first.z;
+
+ // Skip face attribute
data.skipRawData(sizeof(uint16_t));
}
- // Sort the set of vertices (to deduplicate)
- std::sort(verts.begin(), verts.end(),
- [](const Eigen::Vector4d& lhs, const Eigen::Vector4d& rhs)
- {
- if (lhs[0] != rhs[0]) return lhs[0] < rhs[0];
- else if (lhs[1] != rhs[1]) return lhs[1] < rhs[1];
- else if (lhs[2] != rhs[2]) return lhs[2] < rhs[2];
- else return false;
- }
- );
+ // Save indicies as the second element in the array
+ // (so that we can reconstruct triangle order after sorting)
+ for (size_t i=0; i < tri_count*3; ++i)
+ {
+ verts[i].second = i;
+ }
- // This list will store unique vertices
- std::list<Eigen::Vector3f> unique;
+ // Sort the set of vertices (to deduplicate)
+ std::sort(verts.begin(), verts.end());
- // This vector will store triangles as rows of indices
- Eigen::Matrix3Xi indices;
- indices.resize(Eigen::NoChange, tri_count);
+ // This vector will store triangles as sets of 3 indices
+ std::vector<GLuint> indices(tri_count*3);
// Go through the sorted vertex list, deduplicating and creating
// an indexed geometry representation for the triangles.
+ // Unique vertices are moved so that they occupy the first vertex_count
+ // positions in the verts array.
+ size_t vertex_count = 0;
for (auto v : verts)
{
- if (!unique.size() || v[0] != unique.back()[0] ||
- v[1] != unique.back()[1] ||
- v[2] != unique.back()[2])
+ if (!vertex_count || v.first != verts[vertex_count-1].first)
{
- // Switch to a float vector and save in the list.
- Eigen::Vector3f v_;
- v_ << v[0], v[1], v[2];
- unique.push_back(v_);
+ verts[vertex_count++] = v;
}
- indices(int(v[3]) % 3, int(v[3]) / 3) = unique.size() - 1;
+ indices[v.second] = vertex_count - 1;
}
- // Finally, pack unique vertices into a matrix.
- Eigen::Matrix3Xf unique_verts;
- unique_verts.resize(Eigen::NoChange, unique.size());
+ // Finally, pack unique vertices into a flat array.
+ std::vector<GLfloat> unique_verts(vertex_count*3);
+ for (size_t i=0; i < vertex_count; ++i)
{
- auto v = unique.begin();
- for (unsigned i=0; i < unique.size(); ++i)
- {
- unique_verts.col(i) = *(v++);
- }
+ unique_verts[3*i] = verts[i].first.x;
+ unique_verts[3*i + 1] = verts[i].first.y;
+ unique_verts[3*i + 2] = verts[i].first.z;
}
return new Mesh(unique_verts, indices);