summaryrefslogtreecommitdiff
path: root/src/util/numeric.cpp
blob: 99e4cfb5ce24d5804b4342058aa6bd8fecca272a (plain)
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
203
204
205
206
207
/*
Minetest
Copyright (C) 2010-2013 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 "noise.h" // PseudoRandom, PcgRandom
#include "threading/mutex_auto_lock.h"
#include <cstring>
#include <cmath>


// myrand

PcgRandom g_pcgrand;

u32 myrand()
{
	return g_pcgrand.next();
}

void mysrand(unsigned int seed)
{
	g_pcgrand.seed(seed);
}

void myrand_bytes(void *out, size_t len)
{
	g_pcgrand.bytes(out, len);
}

int myrand_range(int min, int max)
{
	return g_pcgrand.range(min, max);
}


/*
	64-bit unaligned version of MurmurHash
*/
u64 murmur_hash_64_ua(const void *key, int len, unsigned int seed)
{
	const u64 m = 0xc6a4a7935bd1e995ULL;
	const int r = 47;
	u64 h = seed ^ (len * m);

	const u8 *data = (const u8 *)key;
	const u8 *end = data + (len / 8) * 8;

	while (data != end) {
		u64 k;
		memcpy(&k, data, sizeof(u64));
		data += sizeof(u64);

		k *= m;
		k ^= k >> r;
		k *= m;

		h ^= k;
		h *= m;
	}

	const unsigned char *data2 = (const unsigned char *)data;
	switch (len & 7) {
		case 7: h ^= (u64)data2[6] << 48;
		case 6: h ^= (u64)data2[5] << 40;
		case 5: h ^= (u64)data2[4] << 32;
		case 4: h ^= (u64)data2[3] << 24;
		case 3: h ^= (u64)data2[2] << 16;
		case 2: h ^= (u64)data2[1] << 8;
		case 1: h ^= (u64)data2[0];
				h *= m;
	}

	h ^= h >> r;
	h *= m;
	h ^= h >> r;

	return h;
}

/*
	blockpos_b: 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
	distance_ptr: return location for distance from the camera
*/
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;

	// Total distance
	f32 d = MYMAX(0, blockpos_relative.getLength() - BLOCK_MAX_RADIUS);

	if (distance_ptr)
		*distance_ptr = d;

	// If block is far away, it's not in sight
	if (d > range)
		return false;

	// If block is (nearly) touching the camera, don't
	// bother validating further (that is, render it anyway)
	if (d == 0)
		return true;

	// Adjust camera position, for purposes of computing the angle,
	// such that a block that has any portion visible with the
	// current camera position will have the center visible at the
	// adjusted postion
	f32 adjdist = BLOCK_MAX_RADIUS / cos((M_PI - camera_fov) / 2);

	// Block position relative to adjusted camera
	v3f blockpos_adj = blockpos - (camera_pos - camera_dir * adjdist);

	// Distance in camera direction (+=front, -=back)
	f32 dforward = blockpos_adj.dotProduct(camera_dir);

	// Cosine of the angle between the camera direction
	// and the block direction (camera_dir is an unit vector)
	f32 cosangle = dforward / blockpos_adj.getLength();

	// If block is not in the field of view, skip it
	// HOTFIX: use sligthly increased angle (+10%) to fix too agressive
	// culling. Somebody have to find out whats wrong with the math here.
	// Previous value: camera_fov / 2
	if (cosangle < std::cos(camera_fov * 0.55f))
		return false;

	return true;
}

s16 adjustDist(s16 dist, float zoom_fov)
{
	// 1.775 ~= 72 * PI / 180 * 1.4, the default FOV on the client.
	// The heuristic threshold for zooming is half of that.
	static constexpr const float threshold_fov = 1.775f / 2.0f;
	if (zoom_fov < 0.001f || zoom_fov > threshold_fov)
		return dist;

	return std::round(dist * std::cbrt((1.0f - std::cos(threshold_fov)) /
		(1.0f - std::cos(zoom_fov / 2.0f))));
}

void setPitchYawRollRad(core::matrix4 &m, const v3f &rot)
{
	f64 a1 = rot.Z, a2 = rot.X, a3 = rot.Y;
	f64 c1 = cos(a1), s1 = sin(a1);
	f64 c2 = cos(a2), s2 = sin(a2);
	f64 c3 = cos(a3), s3 = sin(a3);
	f32 *M = m.pointer();

	M[0] = s1 * s2 * s3 + c1 * c3;
	M[1] = s1 * c2;
	M[2] = s1 * s2 * c3 - c1 * s3;

	M[4] = c1 * s2 * s3 - s1 * c3;
	M[5] = c1 * c2;
	M[6] = c1 * s2 * c3 + s1 * s3;

	M[8] = c2 * s3;
	M[9] = -s2;
	M[10] = c2 * c3;
}

v3f getPitchYawRollRad(const core::matrix4 &m)
{
	const f32 *M = m.pointer();

	f64 a1 = atan2(M[1], M[5]);
	f32 c2 = std::sqrt((f64)M[10]*M[10] + (f64)M[8]*M[8]);
	f32 a2 = atan2f(-M[9], c2);
	f64 c1 = cos(a1);
	f64 s1 = sin(a1);
	f32 a3 = atan2f(s1*M[6] - c1*M[2], c1*M[0] - s1*M[4]);

	return v3f(a2, a3, a1);
}