minetest/src/util/numeric.h

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/*
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Minetest
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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.
*/
#ifndef UTIL_NUMERIC_HEADER
#define UTIL_NUMERIC_HEADER
#include "../irrlichttypes.h"
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#include "../irr_v2d.h"
#include "../irr_v3d.h"
#include "../irr_aabb3d.h"
#include "../threading/mutex.h"
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#include <list>
#include <map>
#include <vector>
#include <algorithm>
/*
* This class permits to cache getFacePosition call results
* This reduces CPU usage and vector calls
*/
class FacePositionCache
{
public:
static std::vector<v3s16> getFacePositions(u16 d);
private:
static void generateFacePosition(u16 d);
static std::map<u16, std::vector<v3s16> > m_cache;
static Mutex m_cache_mutex;
};
class IndentationRaiser
{
public:
IndentationRaiser(u16 *indentation)
{
m_indentation = indentation;
(*m_indentation)++;
}
~IndentationRaiser()
{
(*m_indentation)--;
}
private:
u16 *m_indentation;
};
inline s16 getContainerPos(s16 p, s16 d)
{
return (p>=0 ? p : p-d+1) / d;
}
inline v2s16 getContainerPos(v2s16 p, s16 d)
{
return v2s16(
getContainerPos(p.X, d),
getContainerPos(p.Y, d)
);
}
inline v3s16 getContainerPos(v3s16 p, s16 d)
{
return v3s16(
getContainerPos(p.X, d),
getContainerPos(p.Y, d),
getContainerPos(p.Z, d)
);
}
inline v2s16 getContainerPos(v2s16 p, v2s16 d)
{
return v2s16(
getContainerPos(p.X, d.X),
getContainerPos(p.Y, d.Y)
);
}
inline v3s16 getContainerPos(v3s16 p, v3s16 d)
{
return v3s16(
getContainerPos(p.X, d.X),
getContainerPos(p.Y, d.Y),
getContainerPos(p.Z, d.Z)
);
}
inline void getContainerPosWithOffset(s16 p, s16 d, s16 &container, s16 &offset)
{
container = (p >= 0 ? p : p - d + 1) / d;
offset = p & (d - 1);
}
inline void getContainerPosWithOffset(const v2s16 &p, s16 d, v2s16 &container, v2s16 &offset)
{
getContainerPosWithOffset(p.X, d, container.X, offset.X);
getContainerPosWithOffset(p.Y, d, container.Y, offset.Y);
}
inline void getContainerPosWithOffset(const v3s16 &p, s16 d, v3s16 &container, v3s16 &offset)
{
getContainerPosWithOffset(p.X, d, container.X, offset.X);
getContainerPosWithOffset(p.Y, d, container.Y, offset.Y);
getContainerPosWithOffset(p.Z, d, container.Z, offset.Z);
}
inline bool isInArea(v3s16 p, s16 d)
{
return (
p.X >= 0 && p.X < d &&
p.Y >= 0 && p.Y < d &&
p.Z >= 0 && p.Z < d
);
}
inline bool isInArea(v2s16 p, s16 d)
{
return (
p.X >= 0 && p.X < d &&
p.Y >= 0 && p.Y < d
);
}
inline bool isInArea(v3s16 p, v3s16 d)
{
return (
p.X >= 0 && p.X < d.X &&
p.Y >= 0 && p.Y < d.Y &&
p.Z >= 0 && p.Z < d.Z
);
}
#define rangelim(d, min, max) ((d) < (min) ? (min) : ((d)>(max)?(max):(d)))
#define myfloor(x) ((x) > 0.0 ? (int)(x) : (int)(x) - 1)
inline v3s16 arealim(v3s16 p, s16 d)
{
if(p.X < 0)
p.X = 0;
if(p.Y < 0)
p.Y = 0;
if(p.Z < 0)
p.Z = 0;
if(p.X > d-1)
p.X = d-1;
if(p.Y > d-1)
p.Y = d-1;
if(p.Z > d-1)
p.Z = d-1;
return p;
}
#define ARRLEN(x) (sizeof(x) / sizeof((x)[0]))
#define CONTAINS(c, v) (std::find((c).begin(), (c).end(), (v)) != (c).end())
// The naive swap performs better than the xor version
#define SWAP(t, x, y) do { \
t temp = x; \
x = y; \
y = temp; \
} while (0)
inline void sortBoxVerticies(v3s16 &p1, v3s16 &p2) {
if (p1.X > p2.X)
SWAP(s16, p1.X, p2.X);
if (p1.Y > p2.Y)
SWAP(s16, p1.Y, p2.Y);
if (p1.Z > p2.Z)
SWAP(s16, p1.Z, p2.Z);
}
/** Returns \p f wrapped to the range [-360, 360]
*
* See test.cpp for example cases.
*
* \note This is also used in cases where degrees wrapped to the range [0, 360]
* is innapropriate (e.g. pitch needs negative values)
*
* \internal functionally equivalent -- although precision may vary slightly --
* to fmodf((f), 360.0f) however empirical tests indicate that this approach is
* faster.
*/
inline float modulo360f(float f)
{
int sign;
int whole;
float fraction;
if (f < 0) {
f = -f;
sign = -1;
} else {
sign = 1;
}
whole = f;
fraction = f - whole;
whole %= 360;
return sign * (whole + fraction);
}
/** Returns \p f wrapped to the range [0, 360]
*/
inline float wrapDegrees_0_360(float f)
{
float value = modulo360f(f);
return value < 0 ? value + 360 : value;
}
/** Returns \p f wrapped to the range [-180, 180]
*/
inline float wrapDegrees_180(float f)
{
float value = modulo360f(f + 180);
if (value < 0)
value += 360;
return value - 180;
}
/*
Pseudo-random (VC++ rand() sucks)
*/
#define MYRAND_RANGE 0xffffffff
u32 myrand();
void mysrand(unsigned int seed);
void myrand_bytes(void *out, size_t len);
int myrand_range(int min, int max);
/*
Miscellaneous functions
*/
inline u32 get_bits(u32 x, u32 pos, u32 len)
{
u32 mask = (1 << len) - 1;
return (x >> pos) & mask;
}
inline void set_bits(u32 *x, u32 pos, u32 len, u32 val)
{
u32 mask = (1 << len) - 1;
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*x &= ~(mask << pos);
*x |= (val & mask) << pos;
}
inline u32 calc_parity(u32 v)
{
v ^= v >> 16;
v ^= v >> 8;
v ^= v >> 4;
v &= 0xf;
return (0x6996 >> v) & 1;
}
u64 murmur_hash_64_ua(const void *key, int len, unsigned int seed);
bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir,
f32 camera_fov, f32 range, f32 *distance_ptr=NULL);
/*
Some helper stuff
*/
#define MYMIN(a,b) ((a)<(b)?(a):(b))
#define MYMAX(a,b) ((a)>(b)?(a):(b))
/*
Returns nearest 32-bit integer for given floating point number.
<cmath> and <math.h> in VC++ don't provide round().
*/
inline s32 myround(f32 f)
{
return (s32)(f < 0.f ? (f - 0.5f) : (f + 0.5f));
}
/*
Returns integer position of node in given floating point position
*/
inline v3s16 floatToInt(v3f p, f32 d)
{
v3s16 p2(
(p.X + (p.X>0 ? d/2 : -d/2))/d,
(p.Y + (p.Y>0 ? d/2 : -d/2))/d,
(p.Z + (p.Z>0 ? d/2 : -d/2))/d);
return p2;
}
/*
Returns floating point position of node in given integer position
*/
inline v3f intToFloat(v3s16 p, f32 d)
{
v3f p2(
(f32)p.X * d,
(f32)p.Y * d,
(f32)p.Z * d
);
return p2;
}
// Random helper. Usually d=BS
inline core::aabbox3d<f32> getNodeBox(v3s16 p, float d)
{
return core::aabbox3d<f32>(
(float)p.X * d - 0.5*d,
(float)p.Y * d - 0.5*d,
(float)p.Z * d - 0.5*d,
(float)p.X * d + 0.5*d,
(float)p.Y * d + 0.5*d,
(float)p.Z * d + 0.5*d
);
}
class IntervalLimiter
{
public:
IntervalLimiter():
m_accumulator(0)
{
}
/*
dtime: time from last call to this method
wanted_interval: interval wanted
return value:
true: action should be skipped
false: action should be done
*/
bool step(float dtime, float wanted_interval)
{
m_accumulator += dtime;
if(m_accumulator < wanted_interval)
return false;
m_accumulator -= wanted_interval;
return true;
}
protected:
float m_accumulator;
};
/*
Splits a list into "pages". For example, the list [1,2,3,4,5] split
into two pages would be [1,2,3],[4,5]. This function computes the
minimum and maximum indices of a single page.
length: Length of the list that should be split
page: Page number, 1 <= page <= pagecount
pagecount: The number of pages, >= 1
minindex: Receives the minimum index (inclusive).
maxindex: Receives the maximum index (exclusive).
Ensures 0 <= minindex <= maxindex <= length.
*/
inline void paging(u32 length, u32 page, u32 pagecount, u32 &minindex, u32 &maxindex)
{
if(length < 1 || pagecount < 1 || page < 1 || page > pagecount)
{
// Special cases or invalid parameters
minindex = maxindex = 0;
}
else if(pagecount <= length)
{
// Less pages than entries in the list:
// Each page contains at least one entry
minindex = (length * (page-1) + (pagecount-1)) / pagecount;
maxindex = (length * page + (pagecount-1)) / pagecount;
}
else
{
// More pages than entries in the list:
// Make sure the empty pages are at the end
if(page < length)
{
minindex = page-1;
maxindex = page;
}
else
{
minindex = 0;
maxindex = 0;
}
}
}
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inline float cycle_shift(float value, float by = 0, float max = 1)
{
if (value + by < 0) return max + by + value;
if (value + by > max) return value + by - max;
return value + by;
}
inline bool is_power_of_two(u32 n)
{
return n != 0 && (n & (n-1)) == 0;
}
// Compute next-higher power of 2 efficiently, e.g. for power-of-2 texture sizes.
// Public Domain: https://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
inline u32 npot2(u32 orig) {
orig--;
orig |= orig >> 1;
orig |= orig >> 2;
orig |= orig >> 4;
orig |= orig >> 8;
orig |= orig >> 16;
return orig + 1;
}
#endif