mirror of https://github.com/minetest/minetest.git
104 lines
3.5 KiB
C++
104 lines
3.5 KiB
C++
/*
|
|
Minetest
|
|
Copyright (C) 2023 Vitaliy Lobachevskiy
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU Lesser General Public License as published by
|
|
the Free Software Foundation; either version 2.1 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program 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 Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License along
|
|
with this program; if not, write to the Free Software Foundation, Inc.,
|
|
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*/
|
|
|
|
#include "mesh_compare.h"
|
|
#include <algorithm>
|
|
#include <map>
|
|
#include <stdexcept>
|
|
|
|
static std::vector<Triangle> expandMesh(const std::vector<video::S3DVertex> &vertices, const std::vector<u16> &indices)
|
|
{
|
|
const int n_indices = indices.size();
|
|
const int n_triangles = n_indices / 3;
|
|
if (n_indices % 3)
|
|
throw std::invalid_argument("got fractional number of triangles");
|
|
|
|
std::vector<Triangle> ret(n_triangles);
|
|
for (int i_triangle = 0; i_triangle < n_triangles; i_triangle++) {
|
|
ret.at(i_triangle) = {
|
|
vertices.at(indices.at(3 * i_triangle)),
|
|
vertices.at(indices.at(3 * i_triangle + 1)),
|
|
vertices.at(indices.at(3 * i_triangle + 2)),
|
|
};
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/// Sorts triangle vertices, keeping winding order.
|
|
static Triangle sortTriangle(Triangle t)
|
|
{
|
|
if (t[0] < t[1] && t[0] < t[2]) return {t[0], t[1], t[2]};
|
|
if (t[1] < t[2] && t[1] < t[0]) return {t[1], t[2], t[0]};
|
|
if (t[2] < t[0] && t[2] < t[1]) return {t[2], t[0], t[1]};
|
|
throw std::invalid_argument("got bad triangle");
|
|
}
|
|
|
|
static std::vector<Triangle> canonicalizeMesh(const std::vector<video::S3DVertex> &vertices, const std::vector<u16> &indices)
|
|
{
|
|
std::vector<Triangle> mesh = expandMesh(vertices, indices);
|
|
for (auto &triangle: mesh)
|
|
triangle = sortTriangle(triangle);
|
|
std::sort(std::begin(mesh), std::end(mesh));
|
|
return mesh;
|
|
}
|
|
|
|
bool checkMeshEqual(const std::vector<video::S3DVertex> &vertices, const std::vector<u16> &indices, const std::vector<Triangle> &expected)
|
|
{
|
|
auto actual = canonicalizeMesh(vertices, indices);
|
|
return actual == expected;
|
|
}
|
|
|
|
bool checkMeshEqual(const std::vector<video::S3DVertex> &vertices, const std::vector<u16> &indices, const std::vector<Quad> &expected)
|
|
{
|
|
using QuadRefCount = std::array<int, 4>;
|
|
struct QuadRef {
|
|
unsigned quad_id;
|
|
int quad_part;
|
|
};
|
|
|
|
std::vector<QuadRefCount> refs(expected.size());
|
|
std::map<Triangle, QuadRef> tris;
|
|
for (unsigned k = 0; k < expected.size(); k++) {
|
|
auto &&quad = expected[k];
|
|
// There are 2 ways to split a quad into two triangles. So for each quad,
|
|
// the mesh must contain either triangles 0 and 1, or triangles 2 and 3,
|
|
// from the following list. No more, no less.
|
|
tris.insert({sortTriangle({quad[0], quad[1], quad[2]}), {k, 0}});
|
|
tris.insert({sortTriangle({quad[0], quad[2], quad[3]}), {k, 1}});
|
|
tris.insert({sortTriangle({quad[0], quad[1], quad[3]}), {k, 2}});
|
|
tris.insert({sortTriangle({quad[1], quad[2], quad[3]}), {k, 3}});
|
|
}
|
|
|
|
auto actual = canonicalizeMesh(vertices, indices);
|
|
for (auto &&tri: actual) {
|
|
auto itri = tris.find(tri);
|
|
if (itri == tris.end())
|
|
return false;
|
|
refs[itri->second.quad_id][itri->second.quad_part] += 1;
|
|
}
|
|
|
|
for (unsigned k = 0; k < expected.size(); k++) {
|
|
if (refs[k] != QuadRefCount{1, 1, 0, 0} && refs[k] != QuadRefCount{0, 0, 1, 1})
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|