Mesh library

A small project to learn c++

This repository contains three modules: a .ply file parser, a mesh/graph operator toolset, and a simple render library.

The goal was to implement a fast and simple meshviewer using shaders and c++. All transformations are matrix-free and rely on quaternions to keep things simple and efficient.

Features:

Render:

• displays multiples meshes
• flat shading + specular highlight
• colormaps
• zoom and rotation with the mouse
• shows the current orientation
• perspective projection
• animation using a callback function
• plots 3d vector fields handling large amounts of vectors
• plots 3d curves using extrusion in geometry shader

Mesh:

• curvature, normal, ordered one-ring, and ordered-adjacency computation
• fast edge splitting algorithm, preserving data locality
• Primitives: torus, icosahedron, tetrahedron, cube

Creation of a sphere from an icosahedron.

Tubular curve extruded in geometry shader.

Requirements

• Linux
• make
• opengl 4.6
• glfw

Compilation

The command line executable can be compiled with,

    make -C src ../meshviewer

Tests

The Mesh module has a specific test directory for unit testing. The tests are run with make using Linux diff command and reference files.

Usage

CLI

    ./meshviewer meshes/deform.ply

Code API example:

// Reads a ply file and show the object and it's curvature
#include "mesh/mesh.hpp"
#include "ply/plyfile.hpp"
#include "render/colormap.hpp"
#include "render/trimesh_render.hpp"
#include <vector>

auto main() -> int {

  PlyFile file("meshes/deformHQ.ply");

  // Retrieves the vertice normals from the file.
  std::vector<PropertyName> normal_property_names = {
      PropertyName::nx, PropertyName::ny, PropertyName::nz};

  std::vector<double> normals;
  file.get_subelement_data<double>("vertices", normal_property_names, normals);

  // Creates a mesh object from file data
  Mesh mesh(file.vertices, file.faces);

  // Computes the curvature to define the colors of the rendered object.
  mesh.set_one_ring();
  // get_mean_curvature takes one_ring as argument to make explicit that the
  // method depends on the one-ring and leave the choice to the user to update explicitly.
  std::vector<double> kn = mesh.get_mean_curvature(mesh.one_ring);
  std::vector<double> k = mesh.get_scalar_mean_curvature(kn);


  std::vector<double> colors = Colormap::get_interpolated_colors(k, Colormap::INFERNO);

  MeshRender render(500, 500);
  render.add_mesh(mesh.vertices, mesh.faces, colors);

  // adding another mesh to the display
  Mesh icosahedron = Primitives::icosahedron();
  render.add_mesh(icosahedron.vertices, icosahedron.faces);

  render.render_loop(nullptr, nullptr);
  render.render_finalize();
  return 0;
}