mirror of https://github.com/minetest/minetest.git
111 lines
3.4 KiB
C++
111 lines
3.4 KiB
C++
/*
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Minetest
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Copyright (C) 2015 Nerzhul, Loic Blot <loic.blot@unix-experience.fr>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "face_position_cache.h"
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#include "threading/mutex_auto_lock.h"
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std::unordered_map<u16, std::vector<v3s16>> FacePositionCache::cache;
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std::mutex FacePositionCache::cache_mutex;
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// Calculate the borders of a "d-radius" cube
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const std::vector<v3s16> &FacePositionCache::getFacePositions(u16 d)
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{
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MutexAutoLock lock(cache_mutex);
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std::unordered_map<u16, std::vector<v3s16>>::const_iterator it = cache.find(d);
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if (it != cache.end())
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return it->second;
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return generateFacePosition(d);
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}
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const std::vector<v3s16> &FacePositionCache::generateFacePosition(u16 d)
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{
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cache[d] = std::vector<v3s16>();
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std::vector<v3s16> &c = cache[d];
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if (d == 0) {
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c.emplace_back(0,0,0);
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return c;
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}
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if (d == 1) {
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// This is an optimized sequence of coordinates.
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c.emplace_back(0, 1, 0); // Top
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c.emplace_back(0, 0, 1); // Back
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c.emplace_back(-1, 0, 0); // Left
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c.emplace_back(1, 0, 0); // Right
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c.emplace_back(0, 0,-1); // Front
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c.emplace_back(0,-1, 0); // Bottom
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// 6
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c.emplace_back(-1, 0, 1); // Back left
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c.emplace_back(1, 0, 1); // Back right
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c.emplace_back(-1, 0,-1); // Front left
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c.emplace_back(1, 0,-1); // Front right
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c.emplace_back(-1,-1, 0); // Bottom left
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c.emplace_back(1,-1, 0); // Bottom right
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c.emplace_back(0,-1, 1); // Bottom back
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c.emplace_back(0,-1,-1); // Bottom front
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c.emplace_back(-1, 1, 0); // Top left
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c.emplace_back(1, 1, 0); // Top right
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c.emplace_back(0, 1, 1); // Top back
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c.emplace_back(0, 1,-1); // Top front
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// 18
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c.emplace_back(-1, 1, 1); // Top back-left
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c.emplace_back(1, 1, 1); // Top back-right
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c.emplace_back(-1, 1,-1); // Top front-left
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c.emplace_back(1, 1,-1); // Top front-right
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c.emplace_back(-1,-1, 1); // Bottom back-left
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c.emplace_back(1,-1, 1); // Bottom back-right
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c.emplace_back(-1,-1,-1); // Bottom front-left
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c.emplace_back(1,-1,-1); // Bottom front-right
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// 26
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return c;
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}
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// Take blocks in all sides, starting from y=0 and going +-y
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for (s16 y = 0; y <= d - 1; y++) {
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// Left and right side, including borders
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for (s16 z =- d; z <= d; z++) {
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c.emplace_back(d, y, z);
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c.emplace_back(-d, y, z);
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if (y != 0) {
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c.emplace_back(d, -y, z);
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c.emplace_back(-d, -y, z);
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}
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}
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// Back and front side, excluding borders
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for (s16 x = -d + 1; x <= d - 1; x++) {
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c.emplace_back(x, y, d);
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c.emplace_back(x, y, -d);
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if (y != 0) {
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c.emplace_back(x, -y, d);
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c.emplace_back(x, -y, -d);
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}
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}
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}
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// Take the bottom and top face with borders
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// -d < x < d, y = +-d, -d < z < d
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for (s16 x = -d; x <= d; x++)
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for (s16 z = -d; z <= d; z++) {
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c.emplace_back(x, -d, z);
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c.emplace_back(x, d, z);
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}
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return c;
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}
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