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 // Calculate the borders of a "d-radius" cube
29 void getFacePositions(std::list<v3s16> &list, u16 d)
33 list.push_back(v3s16(0,0,0));
39 This is an optimized sequence of coordinates.
41 list.push_back(v3s16( 0, 1, 0)); // top
42 list.push_back(v3s16( 0, 0, 1)); // back
43 list.push_back(v3s16(-1, 0, 0)); // left
44 list.push_back(v3s16( 1, 0, 0)); // right
45 list.push_back(v3s16( 0, 0,-1)); // front
46 list.push_back(v3s16( 0,-1, 0)); // bottom
48 list.push_back(v3s16(-1, 0, 1)); // back left
49 list.push_back(v3s16( 1, 0, 1)); // back right
50 list.push_back(v3s16(-1, 0,-1)); // front left
51 list.push_back(v3s16( 1, 0,-1)); // front right
52 list.push_back(v3s16(-1,-1, 0)); // bottom left
53 list.push_back(v3s16( 1,-1, 0)); // bottom right
54 list.push_back(v3s16( 0,-1, 1)); // bottom back
55 list.push_back(v3s16( 0,-1,-1)); // bottom front
56 list.push_back(v3s16(-1, 1, 0)); // top left
57 list.push_back(v3s16( 1, 1, 0)); // top right
58 list.push_back(v3s16( 0, 1, 1)); // top back
59 list.push_back(v3s16( 0, 1,-1)); // top front
61 list.push_back(v3s16(-1, 1, 1)); // top back-left
62 list.push_back(v3s16( 1, 1, 1)); // top back-right
63 list.push_back(v3s16(-1, 1,-1)); // top front-left
64 list.push_back(v3s16( 1, 1,-1)); // top front-right
65 list.push_back(v3s16(-1,-1, 1)); // bottom back-left
66 list.push_back(v3s16( 1,-1, 1)); // bottom back-right
67 list.push_back(v3s16(-1,-1,-1)); // bottom front-left
68 list.push_back(v3s16( 1,-1,-1)); // bottom front-right
73 // Take blocks in all sides, starting from y=0 and going +-y
74 for(s16 y=0; y<=d-1; y++)
76 // Left and right side, including borders
77 for(s16 z=-d; z<=d; z++)
79 list.push_back(v3s16(d,y,z));
80 list.push_back(v3s16(-d,y,z));
83 list.push_back(v3s16(d,-y,z));
84 list.push_back(v3s16(-d,-y,z));
87 // Back and front side, excluding borders
88 for(s16 x=-d+1; x<=d-1; x++)
90 list.push_back(v3s16(x,y,d));
91 list.push_back(v3s16(x,y,-d));
94 list.push_back(v3s16(x,-y,d));
95 list.push_back(v3s16(x,-y,-d));
100 // Take the bottom and top face with borders
101 // -d<x<d, y=+-d, -d<z<d
102 for(s16 x=-d; x<=d; x++)
103 for(s16 z=-d; z<=d; z++)
105 list.push_back(v3s16(x,-d,z));
106 list.push_back(v3s16(x,d,z));
114 static unsigned long next = 1;
116 /* RAND_MAX assumed to be 32767 */
119 next = next * 1103515245 + 12345;
120 return((unsigned)(next/65536) % 32768);
123 void mysrand(unsigned seed)
128 int myrand_range(int min, int max)
130 if(max-min > MYRAND_MAX)
132 errorstream<<"WARNING: myrand_range: max-min > MYRAND_MAX"<<std::endl;
133 max = min + MYRAND_MAX;
137 errorstream<<"WARNING: myrand_range: min > max"<<std::endl;
140 return (myrand()%(max-min+1))+min;
143 // 64-bit unaligned version of MurmurHash
144 u64 murmur_hash_64_ua(const void *key, int len, unsigned int seed)
146 const u64 m = 0xc6a4a7935bd1e995ULL;
148 u64 h = seed ^ (len * m);
150 const u64 *data = (const u64 *)key;
151 const u64 *end = data + (len / 8);
153 while (data != end) {
155 memcpy(&k, data, sizeof(u64));
166 const unsigned char *data2 = (const unsigned char *)data;
168 case 7: h ^= (u64)data2[6] << 48;
169 case 6: h ^= (u64)data2[5] << 40;
170 case 5: h ^= (u64)data2[4] << 32;
171 case 4: h ^= (u64)data2[3] << 24;
172 case 3: h ^= (u64)data2[2] << 16;
173 case 2: h ^= (u64)data2[1] << 8;
174 case 1: h ^= (u64)data2[0];
187 blockpos: position of block in block coordinates
188 camera_pos: position of camera in nodes
189 camera_dir: an unit vector pointing to camera direction
192 bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir,
193 f32 camera_fov, f32 range, f32 *distance_ptr)
195 v3s16 blockpos_nodes = blockpos_b * MAP_BLOCKSIZE;
197 // Block center position
199 ((float)blockpos_nodes.X + MAP_BLOCKSIZE/2) * BS,
200 ((float)blockpos_nodes.Y + MAP_BLOCKSIZE/2) * BS,
201 ((float)blockpos_nodes.Z + MAP_BLOCKSIZE/2) * BS
204 // Block position relative to camera
205 v3f blockpos_relative = blockpos - camera_pos;
208 f32 d = blockpos_relative.getLength();
213 // If block is far away, it's not in sight
217 // Maximum radius of a block. The magic number is
218 // sqrt(3.0) / 2.0 in literal form.
219 f32 block_max_radius = 0.866025403784 * MAP_BLOCKSIZE * BS;
221 // If block is (nearly) touching the camera, don't
222 // bother validating further (that is, render it anyway)
223 if(d < block_max_radius)
226 // Adjust camera position, for purposes of computing the angle,
227 // such that a block that has any portion visible with the
228 // current camera position will have the center visible at the
230 f32 adjdist = block_max_radius / cos((M_PI - camera_fov) / 2);
232 // Block position relative to adjusted camera
233 v3f blockpos_adj = blockpos - (camera_pos - camera_dir * adjdist);
235 // Distance in camera direction (+=front, -=back)
236 f32 dforward = blockpos_adj.dotProduct(camera_dir);
238 // Cosine of the angle between the camera direction
239 // and the block direction (camera_dir is an unit vector)
240 f32 cosangle = dforward / blockpos_adj.getLength();
242 // If block is not in the field of view, skip it
243 if(cosangle < cos(camera_fov / 2))