numeric.h

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// Luanti
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
 
#pragma once
 
#include "basic_macros.h"
#include "constants.h"
#include "irrlichttypes.h"
#include "irr_v2d.h"
#include "irr_v3d.h"
#include "irr_aabb3d.h"
#include "SColor.h"
#include <matrix4.h>
#include <cmath>
#include <algorithm>
 
#define rangelim(d, min, max) ((d) < (min) ? (min) : ((d) > (max) ? (max) : (d)))
#define myfloor(x) ((x) < 0.0 ? (int)(x) - 1 : (int)(x))
// The naive swap performs better than the xor version
#define SWAP(t, x, y) do { \
        t temp = x; \
        x = y; \
        y = temp; \
} while (0)
 
// Maximum radius of a block.  The magic number is
// sqrt(3.0) / 2.0 in literal form.
static constexpr const f32 BLOCK_MAX_RADIUS = 0.866025403784f * MAP_BLOCKSIZE * BS;
 
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
        );
}
 
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);
}
 
inline v3s16 componentwise_min(const v3s16 &a, const v3s16 &b)
{
        return v3s16(MYMIN(a.X, b.X), MYMIN(a.Y, b.Y), MYMIN(a.Z, b.Z));
}
 
inline v3s16 componentwise_max(const v3s16 &a, const v3s16 &b)
{
        return v3s16(MYMAX(a.X, b.X), MYMAX(a.Y, b.Y), MYMAX(a.Z, b.Z));
}
 
struct MeshGrid {
        u16 cell_size;
 
        u32 getCellVolume() const { return cell_size * cell_size * cell_size; }
 
        s16 getCellPos(s16 p) const
        {
                return (p - (p < 0) * (cell_size - 1)) / cell_size;
        }
 
        v3s16 getCellPos(v3s16 block_pos) const
        {
                return v3s16(getCellPos(block_pos.X), getCellPos(block_pos.Y), getCellPos(block_pos.Z));
        }
 
        s16 getMeshPos(s16 p) const
        {
                return getCellPos(p) * cell_size;
        }
 
        v3s16 getMeshPos(v3s16 p) const
        {
                return v3s16(getMeshPos(p.X), getMeshPos(p.Y), getMeshPos(p.Z));
        }
 
        bool isMeshPos(v3s16 &p) const
        {
                return p.X % cell_size == 0
                                && p.Y % cell_size == 0
                                && p.Z % cell_size == 0;
        }
 
        u16 getOffsetIndex(v3s16 offset) const
        {
                return (offset.Z * cell_size + offset.Y) * cell_size + offset.X;
        }
};
 
inline float modulo360f(float f)
{
        return fmodf(f, 360.0f);
}
 
 
inline float wrapDegrees_0_360(float f)
{
        float value = modulo360f(f);
        return value < 0 ? value + 360 : value;
}
 
 
inline v3f wrapDegrees_0_360_v3f(v3f v)
{
        v3f value_v3f;
        value_v3f.X = modulo360f(v.X);
        value_v3f.Y = modulo360f(v.Y);
        value_v3f.Z = modulo360f(v.Z);
 
        // Now that values are wrapped, use to get values for certain ranges
        value_v3f.X = value_v3f.X < 0 ? value_v3f.X + 360 : value_v3f.X;
        value_v3f.Y = value_v3f.Y < 0 ? value_v3f.Y + 360 : value_v3f.Y;
        value_v3f.Z = value_v3f.Z < 0 ? value_v3f.Z + 360 : value_v3f.Z;
        return value_v3f;
}
 
 
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);
float myrand_range(float min, float max);
float myrand_float();
 
// Implements a C++11 UniformRandomBitGenerator using the above functions
struct MyRandGenerator {
        typedef u32 result_type;
        static constexpr result_type min() { return 0; }
        static constexpr result_type max() { return MYRAND_RANGE; }
        inline result_type operator()() {
                return myrand();
        }
};
 
/*
        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;
        *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);
 
s16 adjustDist(s16 dist, float zoom_fov);
 
/*
        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));
}
 
inline constexpr f32 sqr(f32 f)
{
        return f * f;
}
 
/*
        Returns integer position of node in given floating point position
*/
inline v3s16 floatToInt(v3f p, f32 d)
{
        return v3s16(
                (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);
}
 
/*
        Returns integer position of node in given double precision position
 */
inline v3s16 doubleToInt(v3d p, double d)
{
        return v3s16(
                (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);
}
 
/*
        Returns floating point position of node in given integer position
*/
inline v3f intToFloat(v3s16 p, f32 d)
{
        return v3f(
                (f32)p.X * d,
                (f32)p.Y * d,
                (f32)p.Z * d
        );
}
 
// Random helper. Usually d=BS
inline aabb3f getNodeBox(v3s16 p, float d)
{
        return aabb3f(
                (float)p.X * d - 0.5f * d,
                (float)p.Y * d - 0.5f * d,
                (float)p.Z * d - 0.5f * d,
                (float)p.X * d + 0.5f * d,
                (float)p.Y * d + 0.5f * d,
                (float)p.Z * d + 0.5f * d
        );
}
 
 
class IntervalLimiter
{
public:
        IntervalLimiter() = default;
 
        bool step(float dtime, float wanted_interval)
        {
                m_accumulator += dtime;
                if (m_accumulator < wanted_interval)
                        return false;
                m_accumulator -= wanted_interval;
                return true;
        }
 
private:
        float m_accumulator = 0.0f;
};
 
 
/*
        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;
                }
        }
}
 
inline float cycle_shift(float value, float by = 0, float max = 1)
{
    if (value + by < 0)   return value + by + max;
    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;
}
 
// Distance between two values in a wrapped (circular) system
template<typename T>
inline unsigned wrappedDifference(T a, T b, const T maximum)
{
        if (a > b)
                std::swap(a, b);
        // now b >= a
        unsigned s = b - a, l = static_cast<unsigned>(maximum - b) + a + 1;
        return std::min(s, l);
}
 
// Gradual steps towards the target value in a wrapped (circular) system
// using the shorter of both ways
template<typename T>
inline void wrappedApproachShortest(T &current, const T target, const T stepsize,
        const T maximum)
{
        T delta = target - current;
        if (delta < 0)
                delta += maximum;
 
        if (delta > stepsize && maximum - delta > stepsize) {
                current += (delta < maximum / 2) ? stepsize : -stepsize;
                if (current >= maximum)
                        current -= maximum;
        } else {
                current = target;
        }
}
 
void setPitchYawRollRad(core::matrix4 &m, v3f rot);
 
inline void setPitchYawRoll(core::matrix4 &m, v3f rot)
{
        setPitchYawRollRad(m, rot * core::DEGTORAD);
}
 
v3f getPitchYawRollRad(const core::matrix4 &m);
 
inline v3f getPitchYawRoll(const core::matrix4 &m)
{
        return getPitchYawRollRad(m) * core::RADTODEG;
}
 
// Muliply the RGB value of a color linearly, and clamp to black/white
inline irr::video::SColor multiplyColorValue(const irr::video::SColor &color, float mod)
{
        return irr::video::SColor(color.getAlpha(),
                        core::clamp<u32>(color.getRed() * mod, 0, 255),
                        core::clamp<u32>(color.getGreen() * mod, 0, 255),
                        core::clamp<u32>(color.getBlue() * mod, 0, 255));
}
 
template <typename T> inline T numericAbsolute(T v) { return v < 0 ? T(-v) : v;                }
template <typename T> inline T numericSign(T v)     { return T(v < 0 ? -1 : (v == 0 ? 0 : 1)); }
 
inline v3f vecAbsolute(v3f v)
{
        return v3f(
                numericAbsolute(v.X),
                numericAbsolute(v.Y),
                numericAbsolute(v.Z)
        );
}
 
inline v3f vecSign(v3f v)
{
        return v3f(
                numericSign(v.X),
                numericSign(v.Y),
                numericSign(v.Z)
        );
}