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/*
Minetest
Copyright (C) 2015 Nerzhul, Loic Blot <loic.blot@unix-experience.fr>
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 "face_position_cache.h"
#include "threading/mutex_auto_lock.h"
std::unordered_map<u16, std::vector<v3s16>> FacePositionCache::cache;
std::mutex FacePositionCache::cache_mutex;
// Calculate the borders of a "d-radius" cube
const std::vector<v3s16> &FacePositionCache::getFacePositions(u16 d)
{
MutexAutoLock lock(cache_mutex);
std::unordered_map<u16, std::vector<v3s16>>::const_iterator it = cache.find(d);
if (it != cache.end())
return it->second;
return generateFacePosition(d);
}
const std::vector<v3s16> &FacePositionCache::generateFacePosition(u16 d)
{
cache[d] = std::vector<v3s16>();
std::vector<v3s16> &c = cache[d];
if (d == 0) {
c.emplace_back(0,0,0);
return c;
}
if (d == 1) {
// This is an optimized sequence of coordinates.
c.emplace_back(0, 1, 0); // Top
c.emplace_back(0, 0, 1); // Back
c.emplace_back(-1, 0, 0); // Left
c.emplace_back(1, 0, 0); // Right
c.emplace_back(0, 0,-1); // Front
c.emplace_back(0,-1, 0); // Bottom
// 6
c.emplace_back(-1, 0, 1); // Back left
c.emplace_back(1, 0, 1); // Back right
c.emplace_back(-1, 0,-1); // Front left
c.emplace_back(1, 0,-1); // Front right
c.emplace_back(-1,-1, 0); // Bottom left
c.emplace_back(1,-1, 0); // Bottom right
c.emplace_back(0,-1, 1); // Bottom back
c.emplace_back(0,-1,-1); // Bottom front
c.emplace_back(-1, 1, 0); // Top left
c.emplace_back(1, 1, 0); // Top right
c.emplace_back(0, 1, 1); // Top back
c.emplace_back(0, 1,-1); // Top front
// 18
c.emplace_back(-1, 1, 1); // Top back-left
c.emplace_back(1, 1, 1); // Top back-right
c.emplace_back(-1, 1,-1); // Top front-left
c.emplace_back(1, 1,-1); // Top front-right
c.emplace_back(-1,-1, 1); // Bottom back-left
c.emplace_back(1,-1, 1); // Bottom back-right
c.emplace_back(-1,-1,-1); // Bottom front-left
c.emplace_back(1,-1,-1); // Bottom front-right
// 26
return c;
}
// Take blocks in all sides, starting from y=0 and going +-y
for (s16 y = 0; y <= d - 1; y++) {
// Left and right side, including borders
for (s16 z =- d; z <= d; z++) {
c.emplace_back(d, y, z);
c.emplace_back(-d, y, z);
if (y != 0) {
c.emplace_back(d, -y, z);
c.emplace_back(-d, -y, z);
}
}
// Back and front side, excluding borders
for (s16 x = -d + 1; x <= d - 1; x++) {
c.emplace_back(x, y, d);
c.emplace_back(x, y, -d);
if (y != 0) {
c.emplace_back(x, -y, d);
c.emplace_back(x, -y, -d);
}
}
}
// Take the bottom and top face with borders
// -d < x < d, y = +-d, -d < z < d
for (s16 x = -d; x <= d; x++)
for (s16 z = -d; z <= d; z++) {
c.emplace_back(x, -d, z);
c.emplace_back(x, d, z);
}
return c;
}
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