fstl/src/loader.cpp
2014-03-25 20:01:46 -04:00

129 lines
3.4 KiB
C++

#include "loader.h"
Loader::Loader(QObject* parent, const QString& filename)
: QThread(parent), filename(filename)
{
// Nothing to do here
}
void Loader::run()
{
Mesh* mesh = load_stl();
if (mesh)
{
emit got_mesh(mesh);
emit loaded_file(filename);
}
}
////////////////////////////////////////////////////////////////////////////////
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;
}
};
typedef std::pair<Vec3, GLuint> Vec3i;
////////////////////////////////////////////////////////////////////////////////
Mesh* Loader::load_stl()
{
QFile file(filename);
file.open(QIODevice::ReadOnly);
if (file.read(5) == "solid")
{
emit error_ascii_stl();
return NULL;
}
// Skip the rest of the header material
file.read(75);
QDataStream data(&file);
data.setByteOrder(QDataStream::LittleEndian);
data.setFloatingPointPrecision(QDataStream::SinglePrecision);
// Load the triangle count from the .stl file
uint32_t tri_count;
data >> tri_count;
// Verify that the file is the right size
if (file.size() != 84 + tri_count*50)
{
emit error_bad_stl();
return NULL;
}
// Extract vertices into an array of xyz, unsigned pairs
QVector<Vec3i> verts(tri_count*3);
// Dummy array, because readRawData is faster than skipRawData
char buffer[sizeof(float)*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.readRawData(buffer, 3*sizeof(float));
// 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.readRawData(buffer, sizeof(uint16_t));
}
// 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;
}
// Sort the set of vertices (to deduplicate)
std::sort(verts.begin(), verts.end());
// 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 (!vertex_count || v.first != verts[vertex_count-1].first)
{
verts[vertex_count++] = v;
}
indices[v.second] = vertex_count - 1;
}
verts.resize(vertex_count);
std::vector<GLfloat> flat_verts;
flat_verts.reserve(vertex_count*3);
for (auto v : verts)
{
flat_verts.push_back(v.first.x);
flat_verts.push_back(v.first.y);
flat_verts.push_back(v.first.z);
}
return new Mesh(flat_verts, indices);
}