134 lines
3.6 KiB
C++
134 lines
3.6 KiB
C++
#include <QFile>
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#include <QDataStream>
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#include <QVector3D>
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#include <algorithm>
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#include <cmath>
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#include "mesh.h"
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////////////////////////////////////////////////////////////////////////////////
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Mesh::Mesh(std::vector<GLfloat> v, std::vector<GLuint> i)
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: vertices(v), indices(i)
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{
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// Nothing to do here
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}
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float Mesh::min(size_t start) const
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{
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float v = vertices[start];
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for (size_t i=start; i < vertices.size(); i += 3)
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{
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v = fmin(v, vertices[i]);
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}
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return v;
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}
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float Mesh::max(size_t start) const
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{
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float v = vertices[start];
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for (size_t i=start; i < vertices.size(); i += 3)
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{
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v = fmax(v, vertices[i]);
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}
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return v;
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}
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////////////////////////////////////////////////////////////////////////////////
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struct Vec3
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{
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GLfloat x, y, z;
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bool operator!=(const Vec3& rhs) const
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{
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return x != rhs.x || y != rhs.y || z != rhs.z;
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}
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bool operator<(const Vec3& rhs) const
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{
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if (x != rhs.x) return x < rhs.x;
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else if (y != rhs.y) return y < rhs.y;
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else if (z != rhs.z) return z < rhs.z;
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else return false;
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}
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};
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typedef std::pair<Vec3, GLuint> Vec3i;
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////////////////////////////////////////////////////////////////////////////////
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Mesh* Mesh::load_stl(const QString& filename)
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{
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QFile file(filename);
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file.open(QIODevice::ReadOnly);
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QDataStream data(&file);
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data.setByteOrder(QDataStream::LittleEndian);
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data.setFloatingPointPrecision(QDataStream::SinglePrecision);
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// Skip .stl file header
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data.skipRawData(80);
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// Load the triangle count from the .stl file
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uint32_t tri_count;
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data >> tri_count;
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// Extract vertices into an array of xyz, unsigned pairs
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QVector<Vec3i> verts(tri_count*3);
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// Dummy array, because readRawData is faster than skipRawData
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char buffer[sizeof(float)*3];
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// Store vertices in the array, processing one triangle at a time.
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for (auto v=verts.begin(); v != verts.end(); v += 3)
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{
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// Skip face's normal vector
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data.readRawData(buffer, 3*sizeof(float));
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// Load vertex data from .stl file into vertices
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data >> v[0].first.x >> v[0].first.y >> v[0].first.z;
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data >> v[1].first.x >> v[1].first.y >> v[1].first.z;
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data >> v[2].first.x >> v[2].first.y >> v[2].first.z;
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// Skip face attribute
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data.readRawData(buffer, sizeof(uint16_t));
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}
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// Save indicies as the second element in the array
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// (so that we can reconstruct triangle order after sorting)
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for (size_t i=0; i < tri_count*3; ++i)
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{
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verts[i].second = i;
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}
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// Sort the set of vertices (to deduplicate)
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std::sort(verts.begin(), verts.end());
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// This vector will store triangles as sets of 3 indices
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std::vector<GLuint> indices(tri_count*3);
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// Go through the sorted vertex list, deduplicating and creating
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// an indexed geometry representation for the triangles.
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// Unique vertices are moved so that they occupy the first vertex_count
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// positions in the verts array.
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size_t vertex_count = 0;
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for (auto v : verts)
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{
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if (!vertex_count || v.first != verts[vertex_count-1].first)
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{
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verts[vertex_count++] = v;
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}
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indices[v.second] = vertex_count - 1;
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}
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verts.resize(vertex_count);
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std::vector<GLfloat> flat_verts;
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flat_verts.reserve(vertex_count*3);
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for (auto v : verts)
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{
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flat_verts.push_back(v.first.x);
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flat_verts.push_back(v.first.y);
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flat_verts.push_back(v.first.z);
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}
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return new Mesh(flat_verts, indices);
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}
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