3 Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as published by
7 the Free Software Foundation; either version 2.1 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public License along
16 with this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
21 #include "mathconstants.h"
24 #include "../constants.h" // BS, MAP_BLOCKSIZE
28 std::map<u16, std::vector<v3s16> > FacePositionCache::m_cache;
29 // Calculate the borders of a "d-radius" cube
30 std::vector<v3s16> FacePositionCache::getFacePositions(u16 d)
32 if (m_cache.find(d) != m_cache.end())
35 generateFacePosition(d);
40 void FacePositionCache::generateFacePosition(u16 d)
42 m_cache[d] = std::vector<v3s16>();
44 m_cache[d].push_back(v3s16(0,0,0));
49 This is an optimized sequence of coordinates.
51 m_cache[d].push_back(v3s16( 0, 1, 0)); // top
52 m_cache[d].push_back(v3s16( 0, 0, 1)); // back
53 m_cache[d].push_back(v3s16(-1, 0, 0)); // left
54 m_cache[d].push_back(v3s16( 1, 0, 0)); // right
55 m_cache[d].push_back(v3s16( 0, 0,-1)); // front
56 m_cache[d].push_back(v3s16( 0,-1, 0)); // bottom
58 m_cache[d].push_back(v3s16(-1, 0, 1)); // back left
59 m_cache[d].push_back(v3s16( 1, 0, 1)); // back right
60 m_cache[d].push_back(v3s16(-1, 0,-1)); // front left
61 m_cache[d].push_back(v3s16( 1, 0,-1)); // front right
62 m_cache[d].push_back(v3s16(-1,-1, 0)); // bottom left
63 m_cache[d].push_back(v3s16( 1,-1, 0)); // bottom right
64 m_cache[d].push_back(v3s16( 0,-1, 1)); // bottom back
65 m_cache[d].push_back(v3s16( 0,-1,-1)); // bottom front
66 m_cache[d].push_back(v3s16(-1, 1, 0)); // top left
67 m_cache[d].push_back(v3s16( 1, 1, 0)); // top right
68 m_cache[d].push_back(v3s16( 0, 1, 1)); // top back
69 m_cache[d].push_back(v3s16( 0, 1,-1)); // top front
71 m_cache[d].push_back(v3s16(-1, 1, 1)); // top back-left
72 m_cache[d].push_back(v3s16( 1, 1, 1)); // top back-right
73 m_cache[d].push_back(v3s16(-1, 1,-1)); // top front-left
74 m_cache[d].push_back(v3s16( 1, 1,-1)); // top front-right
75 m_cache[d].push_back(v3s16(-1,-1, 1)); // bottom back-left
76 m_cache[d].push_back(v3s16( 1,-1, 1)); // bottom back-right
77 m_cache[d].push_back(v3s16(-1,-1,-1)); // bottom front-left
78 m_cache[d].push_back(v3s16( 1,-1,-1)); // bottom front-right
83 // Take blocks in all sides, starting from y=0 and going +-y
84 for(s16 y=0; y<=d-1; y++) {
85 // Left and right side, including borders
86 for(s16 z=-d; z<=d; z++) {
87 m_cache[d].push_back(v3s16(d,y,z));
88 m_cache[d].push_back(v3s16(-d,y,z));
90 m_cache[d].push_back(v3s16(d,-y,z));
91 m_cache[d].push_back(v3s16(-d,-y,z));
94 // Back and front side, excluding borders
95 for(s16 x=-d+1; x<=d-1; x++) {
96 m_cache[d].push_back(v3s16(x,y,d));
97 m_cache[d].push_back(v3s16(x,y,-d));
99 m_cache[d].push_back(v3s16(x,-y,d));
100 m_cache[d].push_back(v3s16(x,-y,-d));
105 // Take the bottom and top face with borders
106 // -d<x<d, y=+-d, -d<z<d
107 for(s16 x=-d; x<=d; x++)
108 for(s16 z=-d; z<=d; z++) {
109 m_cache[d].push_back(v3s16(x,-d,z));
110 m_cache[d].push_back(v3s16(x,d,z));
118 static unsigned long next = 1;
120 /* RAND_MAX assumed to be 32767 */
123 next = next * 1103515245 + 12345;
124 return((unsigned)(next/65536) % 32768);
127 void mysrand(unsigned seed)
132 int myrand_range(int min, int max)
134 if(max-min > MYRAND_MAX)
136 errorstream<<"WARNING: myrand_range: max-min > MYRAND_MAX"<<std::endl;
137 max = min + MYRAND_MAX;
141 errorstream<<"WARNING: myrand_range: min > max"<<std::endl;
144 return (myrand()%(max-min+1))+min;
147 // 64-bit unaligned version of MurmurHash
148 u64 murmur_hash_64_ua(const void *key, int len, unsigned int seed)
150 const u64 m = 0xc6a4a7935bd1e995ULL;
152 u64 h = seed ^ (len * m);
154 const u64 *data = (const u64 *)key;
155 const u64 *end = data + (len / 8);
157 while (data != end) {
159 memcpy(&k, data, sizeof(u64));
170 const unsigned char *data2 = (const unsigned char *)data;
172 case 7: h ^= (u64)data2[6] << 48;
173 case 6: h ^= (u64)data2[5] << 40;
174 case 5: h ^= (u64)data2[4] << 32;
175 case 4: h ^= (u64)data2[3] << 24;
176 case 3: h ^= (u64)data2[2] << 16;
177 case 2: h ^= (u64)data2[1] << 8;
178 case 1: h ^= (u64)data2[0];
191 blockpos: position of block in block coordinates
192 camera_pos: position of camera in nodes
193 camera_dir: an unit vector pointing to camera direction
196 bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir,
197 f32 camera_fov, f32 range, f32 *distance_ptr)
199 v3s16 blockpos_nodes = blockpos_b * MAP_BLOCKSIZE;
201 // Block center position
203 ((float)blockpos_nodes.X + MAP_BLOCKSIZE/2) * BS,
204 ((float)blockpos_nodes.Y + MAP_BLOCKSIZE/2) * BS,
205 ((float)blockpos_nodes.Z + MAP_BLOCKSIZE/2) * BS
208 // Block position relative to camera
209 v3f blockpos_relative = blockpos - camera_pos;
212 f32 d = blockpos_relative.getLength();
217 // If block is far away, it's not in sight
221 // Maximum radius of a block. The magic number is
222 // sqrt(3.0) / 2.0 in literal form.
223 f32 block_max_radius = 0.866025403784 * MAP_BLOCKSIZE * BS;
225 // If block is (nearly) touching the camera, don't
226 // bother validating further (that is, render it anyway)
227 if(d < block_max_radius)
230 // Adjust camera position, for purposes of computing the angle,
231 // such that a block that has any portion visible with the
232 // current camera position will have the center visible at the
234 f32 adjdist = block_max_radius / cos((M_PI - camera_fov) / 2);
236 // Block position relative to adjusted camera
237 v3f blockpos_adj = blockpos - (camera_pos - camera_dir * adjdist);
239 // Distance in camera direction (+=front, -=back)
240 f32 dforward = blockpos_adj.dotProduct(camera_dir);
242 // Cosine of the angle between the camera direction
243 // and the block direction (camera_dir is an unit vector)
244 f32 cosangle = dforward / blockpos_adj.getLength();
246 // If block is not in the field of view, skip it
247 if(cosangle < cos(camera_fov / 2))