1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
|
/*
Minetest-c55
Copyright (C) 2010-2012 celeron55, Perttu Ahola <celeron55@gmail.com>
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 "numeric.h"
#include "../log.h"
#include "../constants.h" // BS, MAP_BLOCKSIZE
#include <iostream>
// Calculate the borders of a "d-radius" cube
void getFacePositions(core::list<v3s16> &list, u16 d)
{
if(d == 0)
{
list.push_back(v3s16(0,0,0));
return;
}
if(d == 1)
{
/*
This is an optimized sequence of coordinates.
*/
list.push_back(v3s16( 0, 1, 0)); // top
list.push_back(v3s16( 0, 0, 1)); // back
list.push_back(v3s16(-1, 0, 0)); // left
list.push_back(v3s16( 1, 0, 0)); // right
list.push_back(v3s16( 0, 0,-1)); // front
list.push_back(v3s16( 0,-1, 0)); // bottom
// 6
list.push_back(v3s16(-1, 0, 1)); // back left
list.push_back(v3s16( 1, 0, 1)); // back right
list.push_back(v3s16(-1, 0,-1)); // front left
list.push_back(v3s16( 1, 0,-1)); // front right
list.push_back(v3s16(-1,-1, 0)); // bottom left
list.push_back(v3s16( 1,-1, 0)); // bottom right
list.push_back(v3s16( 0,-1, 1)); // bottom back
list.push_back(v3s16( 0,-1,-1)); // bottom front
list.push_back(v3s16(-1, 1, 0)); // top left
list.push_back(v3s16( 1, 1, 0)); // top right
list.push_back(v3s16( 0, 1, 1)); // top back
list.push_back(v3s16( 0, 1,-1)); // top front
// 18
list.push_back(v3s16(-1, 1, 1)); // top back-left
list.push_back(v3s16( 1, 1, 1)); // top back-right
list.push_back(v3s16(-1, 1,-1)); // top front-left
list.push_back(v3s16( 1, 1,-1)); // top front-right
list.push_back(v3s16(-1,-1, 1)); // bottom back-left
list.push_back(v3s16( 1,-1, 1)); // bottom back-right
list.push_back(v3s16(-1,-1,-1)); // bottom front-left
list.push_back(v3s16( 1,-1,-1)); // bottom front-right
// 26
return;
}
// 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++)
{
list.push_back(v3s16(d,y,z));
list.push_back(v3s16(-d,y,z));
if(y != 0)
{
list.push_back(v3s16(d,-y,z));
list.push_back(v3s16(-d,-y,z));
}
}
// Back and front side, excluding borders
for(s16 x=-d+1; x<=d-1; x++)
{
list.push_back(v3s16(x,y,d));
list.push_back(v3s16(x,y,-d));
if(y != 0)
{
list.push_back(v3s16(x,-y,d));
list.push_back(v3s16(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++)
{
list.push_back(v3s16(x,-d,z));
list.push_back(v3s16(x,d,z));
}
}
/*
myrand
*/
static unsigned long next = 1;
/* RAND_MAX assumed to be 32767 */
int myrand(void)
{
next = next * 1103515245 + 12345;
return((unsigned)(next/65536) % 32768);
}
void mysrand(unsigned seed)
{
next = seed;
}
int myrand_range(int min, int max)
{
if(max-min > MYRAND_MAX)
{
errorstream<<"WARNING: myrand_range: max-min > MYRAND_MAX"<<std::endl;
max = min + MYRAND_MAX;
}
if(min > max)
{
errorstream<<"WARNING: myrand_range: min > max"<<std::endl;
return max;
}
return (myrand()%(max-min+1))+min;
}
/*
blockpos: position of block in block coordinates
camera_pos: position of camera in nodes
camera_dir: an unit vector pointing to camera direction
range: viewing range
*/
bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir,
f32 camera_fov, f32 range, f32 *distance_ptr)
{
v3s16 blockpos_nodes = blockpos_b * MAP_BLOCKSIZE;
// Block center position
v3f blockpos(
((float)blockpos_nodes.X + MAP_BLOCKSIZE/2) * BS,
((float)blockpos_nodes.Y + MAP_BLOCKSIZE/2) * BS,
((float)blockpos_nodes.Z + MAP_BLOCKSIZE/2) * BS
);
// Block position relative to camera
v3f blockpos_relative = blockpos - camera_pos;
// Distance in camera direction (+=front, -=back)
f32 dforward = blockpos_relative.dotProduct(camera_dir);
// Total distance
f32 d = blockpos_relative.getLength();
if(distance_ptr)
*distance_ptr = d;
// If block is very close, it is always in sight
if(d < 1.44*1.44*MAP_BLOCKSIZE*BS/2)
return true;
// If block is far away, it's not in sight
if(d > range)
return false;
// Maximum radius of a block
f32 block_max_radius = 0.5*1.44*1.44*MAP_BLOCKSIZE*BS;
// If block is (nearly) touching the camera, don't
// bother validating further (that is, render it anyway)
if(d < block_max_radius)
return true;
// Cosine of the angle between the camera direction
// and the block direction (camera_dir is an unit vector)
f32 cosangle = dforward / d;
// Compensate for the size of the block
// (as the block has to be shown even if it's a bit off FOV)
// This is an estimate, plus an arbitary factor
cosangle += block_max_radius / d * 0.5;
// If block is not in the field of view, skip it
if(cosangle < cos(camera_fov / 2))
return false;
return true;
}
|
