mirror of https://github.com/minetest/minetest.git
252 lines
6.8 KiB
C++
252 lines
6.8 KiB
C++
/*
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Minetest
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Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
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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 "numeric.h"
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#include "mathconstants.h"
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#include "log.h"
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#include "../constants.h" // BS, MAP_BLOCKSIZE
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#include "../noise.h" // PseudoRandom, PcgRandom
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#include "../threading/mutex_auto_lock.h"
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#include <string.h>
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#include <iostream>
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std::map<u16, std::vector<v3s16> > FacePositionCache::m_cache;
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Mutex FacePositionCache::m_cache_mutex;
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// Calculate the borders of a "d-radius" cube
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// TODO: Make it work without mutex and data races, probably thread-local
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std::vector<v3s16> FacePositionCache::getFacePositions(u16 d)
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{
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MutexAutoLock cachelock(m_cache_mutex);
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if (m_cache.find(d) != m_cache.end())
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return m_cache[d];
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generateFacePosition(d);
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return m_cache[d];
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}
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void FacePositionCache::generateFacePosition(u16 d)
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{
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m_cache[d] = std::vector<v3s16>();
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if(d == 0) {
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m_cache[d].push_back(v3s16(0,0,0));
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return;
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}
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if(d == 1) {
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/*
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This is an optimized sequence of coordinates.
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*/
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m_cache[d].push_back(v3s16( 0, 1, 0)); // top
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m_cache[d].push_back(v3s16( 0, 0, 1)); // back
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m_cache[d].push_back(v3s16(-1, 0, 0)); // left
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m_cache[d].push_back(v3s16( 1, 0, 0)); // right
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m_cache[d].push_back(v3s16( 0, 0,-1)); // front
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m_cache[d].push_back(v3s16( 0,-1, 0)); // bottom
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// 6
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m_cache[d].push_back(v3s16(-1, 0, 1)); // back left
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m_cache[d].push_back(v3s16( 1, 0, 1)); // back right
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m_cache[d].push_back(v3s16(-1, 0,-1)); // front left
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m_cache[d].push_back(v3s16( 1, 0,-1)); // front right
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m_cache[d].push_back(v3s16(-1,-1, 0)); // bottom left
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m_cache[d].push_back(v3s16( 1,-1, 0)); // bottom right
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m_cache[d].push_back(v3s16( 0,-1, 1)); // bottom back
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m_cache[d].push_back(v3s16( 0,-1,-1)); // bottom front
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m_cache[d].push_back(v3s16(-1, 1, 0)); // top left
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m_cache[d].push_back(v3s16( 1, 1, 0)); // top right
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m_cache[d].push_back(v3s16( 0, 1, 1)); // top back
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m_cache[d].push_back(v3s16( 0, 1,-1)); // top front
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// 18
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m_cache[d].push_back(v3s16(-1, 1, 1)); // top back-left
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m_cache[d].push_back(v3s16( 1, 1, 1)); // top back-right
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m_cache[d].push_back(v3s16(-1, 1,-1)); // top front-left
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m_cache[d].push_back(v3s16( 1, 1,-1)); // top front-right
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m_cache[d].push_back(v3s16(-1,-1, 1)); // bottom back-left
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m_cache[d].push_back(v3s16( 1,-1, 1)); // bottom back-right
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m_cache[d].push_back(v3s16(-1,-1,-1)); // bottom front-left
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m_cache[d].push_back(v3s16( 1,-1,-1)); // bottom front-right
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// 26
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return;
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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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m_cache[d].push_back(v3s16(d,y,z));
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m_cache[d].push_back(v3s16(-d,y,z));
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if(y != 0) {
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m_cache[d].push_back(v3s16(d,-y,z));
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m_cache[d].push_back(v3s16(-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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m_cache[d].push_back(v3s16(x,y,d));
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m_cache[d].push_back(v3s16(x,y,-d));
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if(y != 0) {
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m_cache[d].push_back(v3s16(x,-y,d));
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m_cache[d].push_back(v3s16(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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m_cache[d].push_back(v3s16(x,-d,z));
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m_cache[d].push_back(v3s16(x,d,z));
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}
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}
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/*
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myrand
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*/
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PcgRandom g_pcgrand;
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u32 myrand()
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{
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return g_pcgrand.next();
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}
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void mysrand(unsigned int seed)
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{
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g_pcgrand.seed(seed);
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}
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void myrand_bytes(void *out, size_t len)
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{
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g_pcgrand.bytes(out, len);
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}
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int myrand_range(int min, int max)
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{
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return g_pcgrand.range(min, max);
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}
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/*
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64-bit unaligned version of MurmurHash
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*/
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u64 murmur_hash_64_ua(const void *key, int len, unsigned int seed)
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{
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const u64 m = 0xc6a4a7935bd1e995ULL;
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const int r = 47;
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u64 h = seed ^ (len * m);
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const u64 *data = (const u64 *)key;
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const u64 *end = data + (len / 8);
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while (data != end) {
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u64 k;
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memcpy(&k, data, sizeof(u64));
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data++;
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k *= m;
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k ^= k >> r;
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k *= m;
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h ^= k;
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h *= m;
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}
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const unsigned char *data2 = (const unsigned char *)data;
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switch (len & 7) {
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case 7: h ^= (u64)data2[6] << 48;
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case 6: h ^= (u64)data2[5] << 40;
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case 5: h ^= (u64)data2[4] << 32;
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case 4: h ^= (u64)data2[3] << 24;
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case 3: h ^= (u64)data2[2] << 16;
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case 2: h ^= (u64)data2[1] << 8;
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case 1: h ^= (u64)data2[0];
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h *= m;
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}
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h ^= h >> r;
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h *= m;
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h ^= h >> r;
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return h;
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}
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/*
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blockpos: position of block in block coordinates
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camera_pos: position of camera in nodes
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camera_dir: an unit vector pointing to camera direction
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range: viewing range
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*/
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bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir,
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f32 camera_fov, f32 range, f32 *distance_ptr)
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{
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v3s16 blockpos_nodes = blockpos_b * MAP_BLOCKSIZE;
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// Block center position
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v3f blockpos(
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((float)blockpos_nodes.X + MAP_BLOCKSIZE/2) * BS,
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((float)blockpos_nodes.Y + MAP_BLOCKSIZE/2) * BS,
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((float)blockpos_nodes.Z + MAP_BLOCKSIZE/2) * BS
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);
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// Block position relative to camera
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v3f blockpos_relative = blockpos - camera_pos;
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// Total distance
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f32 d = blockpos_relative.getLength();
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if(distance_ptr)
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*distance_ptr = d;
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// If block is far away, it's not in sight
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if(d > range)
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return false;
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// Maximum radius of a block. The magic number is
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// sqrt(3.0) / 2.0 in literal form.
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f32 block_max_radius = 0.866025403784 * MAP_BLOCKSIZE * BS;
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// If block is (nearly) touching the camera, don't
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// bother validating further (that is, render it anyway)
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if(d < block_max_radius)
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return true;
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// Adjust camera position, for purposes of computing the angle,
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// such that a block that has any portion visible with the
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// current camera position will have the center visible at the
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// adjusted postion
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f32 adjdist = block_max_radius / cos((M_PI - camera_fov) / 2);
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// Block position relative to adjusted camera
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v3f blockpos_adj = blockpos - (camera_pos - camera_dir * adjdist);
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// Distance in camera direction (+=front, -=back)
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f32 dforward = blockpos_adj.dotProduct(camera_dir);
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// Cosine of the angle between the camera direction
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// and the block direction (camera_dir is an unit vector)
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f32 cosangle = dforward / blockpos_adj.getLength();
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// If block is not in the field of view, skip it
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if(cosangle < cos(camera_fov / 2))
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return false;
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return true;
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}
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