/*
* Copyright (C) 2020 Christopher J. Howard
*
* This file is part of Antkeeper source code.
*
* Antkeeper source code is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Antkeeper source code is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Antkeeper source code. If not, see .
*/
#include "mesh-functions.hpp"
#include "math/math.hpp"
#include
struct edge_hasher
{
std::size_t operator()(const std::array& v) const noexcept
{
std::size_t hash = std::hash()(v[0]);
return hash ^ (std::hash()(v[1]) + 0x9e3779b9 + (hash << 6) + (hash >> 2));
}
};
void create_triangle_mesh(mesh& mesh, const std::vector& vertices, const std::vector>& triangles)
{
for (const auto& vertex: vertices)
mesh.add_vertex(vertex);
std::unordered_map, ::mesh::edge*, edge_hasher> edge_map;
const std::vector& mesh_vertices = mesh.get_vertices();
std::vector<::mesh::edge*> loop(3);
for (const auto& triangle: triangles)
{
::mesh::vertex* triangle_vertices[3] =
{
mesh_vertices[triangle[0]],
mesh_vertices[triangle[1]],
mesh_vertices[triangle[2]]
};
for (int j = 0; j < 3; ++j)
{
::mesh::vertex* start = triangle_vertices[j];
::mesh::vertex* end = triangle_vertices[(j + 1) % 3];
if (auto it = edge_map.find({start->index, end->index}); it != edge_map.end())
{
loop[j] = it->second;
}
else
{
loop[j] = mesh.add_edge(start, end);
edge_map[{start->index, end->index}] = loop[j];
edge_map[{end->index, start->index}] = loop[j]->symmetric;
}
}
mesh.add_face(loop);
}
}
void calculate_face_normals(float* normals, const mesh& mesh)
{
const std::vector& faces = mesh.get_faces();
for (std::size_t i = 0; i < faces.size(); ++i)
{
const mesh::face& face = *(faces[i]);
float3& normal = reinterpret_cast(normals[i * 3]);
const float3& a = reinterpret_cast(face.edge->vertex->position);
const float3& b = reinterpret_cast(face.edge->next->vertex->position);
const float3& c = reinterpret_cast(face.edge->previous->vertex->position);
normal = math::normalize(math::cross(b - a, c - a));
}
}
aabb calculate_bounds(const mesh& mesh)
{
float3 bounds_min;
float3 bounds_max;
for (int i = 0; i < 3; ++i)
{
bounds_min[i] = std::numeric_limits::infinity();
bounds_max[i] = -std::numeric_limits::infinity();
}
for (const mesh::vertex* vertex: mesh.get_vertices())
{
const auto& position = vertex->position;
for (int i = 0; i < 3; ++i)
{
bounds_min[i] = std::min(bounds_min[i], position[i]);
bounds_max[i] = std::max(bounds_max[i], position[i]);
}
}
return aabb{bounds_min, bounds_max};
}