noise.h

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/*
 * Minetest
 * Copyright (C) 2010-2014 celeron55, Perttu Ahola <celeron55@gmail.com>
 * Copyright (C) 2010-2014 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *  1. Redistributions of source code must retain the above copyright notice, this list of
 *     conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright notice, this list
 *     of conditions and the following disclaimer in the documentation and/or other materials
 *     provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#pragma once
 
#include "irr_v3d.h"
#include "exceptions.h"
#include "util/string.h"
 
#if defined(RANDOM_MIN)
#undef RANDOM_MIN
#endif
#if defined(RANDOM_MAX)
#undef RANDOM_MAX
#endif
 
extern FlagDesc flagdesc_noiseparams[];
 
// Note: this class is not polymorphic so that its high level of
// optimizability may be preserved in the common use case
class PseudoRandom {
public:
        const static u32 RANDOM_RANGE = 32767;
 
        inline PseudoRandom(s32 seed_=0)
        {
                seed(seed_);
        }
 
        inline void seed(s32 seed)
        {
                m_next = seed;
        }
 
        inline u32 next()
        {
                m_next = static_cast<u32>(m_next) * 1103515245U + 12345U;
                // Signed division is required due to backwards compatibility
                return static_cast<u32>(m_next / 65536) % (RANDOM_RANGE + 1U);
        }
 
        inline s32 range(s32 min, s32 max)
        {
                if (max < min)
                        throw PrngException("Invalid range (max < min)");
                /*
                Here, we ensure the range is not too large relative to RANDOM_MAX,
                as otherwise the effects of bias would become noticeable.  Unlike
                PcgRandom, we cannot modify this RNG's range as it would change the
                output of this RNG for reverse compatibility.
                */
                if (static_cast<u32>(max - min) > (RANDOM_RANGE + 1) / 5)
                        throw PrngException("Range too large");
 
                return (next() % (max - min + 1)) + min;
        }
 
        // Allow save and restore of state
        inline s32 getState() const
        {
                return m_next;
        }
private:
        s32 m_next;
};
 
class PcgRandom {
public:
        const static s32 RANDOM_MIN   = -0x7fffffff - 1;
        const static s32 RANDOM_MAX   = 0x7fffffff;
        const static u32 RANDOM_RANGE = 0xffffffff;
 
        PcgRandom(u64 state=0x853c49e6748fea9bULL, u64 seq=0xda3e39cb94b95bdbULL);
        void seed(u64 state, u64 seq=0xda3e39cb94b95bdbULL);
        u32 next();
        u32 range(u32 bound);
        s32 range(s32 min, s32 max);
        void bytes(void *out, size_t len);
        s32 randNormalDist(s32 min, s32 max, int num_trials=6);
 
        // Allow save and restore of state
        void getState(u64 state[2]) const;
        void setState(const u64 state[2]);
private:
        u64 m_state;
        u64 m_inc;
};
 
#define NOISE_FLAG_DEFAULTS    0x01
#define NOISE_FLAG_EASED       0x02
#define NOISE_FLAG_ABSVALUE    0x04
 
#define NOISE_FLAG_POINTBUFFER 0x08
#define NOISE_FLAG_SIMPLEX     0x10
 
struct NoiseParams {
        float offset = 0.0f;
        float scale = 1.0f;
        v3f spread = v3f(250, 250, 250);
        s32 seed = 12345;
        u16 octaves = 3;
        float persist = 0.6f;
        float lacunarity = 2.0f;
        u32 flags = NOISE_FLAG_DEFAULTS;
 
        NoiseParams() = default;
 
        NoiseParams(float offset_, float scale_, const v3f &spread_, s32 seed_,
                u16 octaves_, float persist_, float lacunarity_,
                u32 flags_=NOISE_FLAG_DEFAULTS)
        {
                offset     = offset_;
                scale      = scale_;
                spread     = spread_;
                seed       = seed_;
                octaves    = octaves_;
                persist    = persist_;
                lacunarity = lacunarity_;
                flags      = flags_;
        }
};
 
class Noise {
public:
        NoiseParams np;
        s32 seed;
        u32 sx;
        u32 sy;
        u32 sz;
        float *noise_buf = nullptr;
        float *gradient_buf = nullptr;
        float *persist_buf = nullptr;
        float *result = nullptr;
 
        Noise(const NoiseParams *np, s32 seed, u32 sx, u32 sy, u32 sz=1);
        ~Noise();
 
        void setSize(u32 sx, u32 sy, u32 sz=1);
        void setSpreadFactor(v3f spread);
        void setOctaves(int octaves);
 
        void gradientMap2D(
                float x, float y,
                float step_x, float step_y,
                s32 seed);
        void gradientMap3D(
                float x, float y, float z,
                float step_x, float step_y, float step_z,
                s32 seed);
 
        float *perlinMap2D(float x, float y, float *persistence_map=NULL);
        float *perlinMap3D(float x, float y, float z, float *persistence_map=NULL);
 
        inline float *perlinMap2D_PO(float x, float xoff, float y, float yoff,
                float *persistence_map=NULL)
        {
                return perlinMap2D(
                        x + xoff * np.spread.X,
                        y + yoff * np.spread.Y,
                        persistence_map);
        }
 
        inline float *perlinMap3D_PO(float x, float xoff, float y, float yoff,
                float z, float zoff, float *persistence_map=NULL)
        {
                return perlinMap3D(
                        x + xoff * np.spread.X,
                        y + yoff * np.spread.Y,
                        z + zoff * np.spread.Z,
                        persistence_map);
        }
 
private:
        void allocBuffers();
        void resizeNoiseBuf(bool is3d);
        void updateResults(float g, float *gmap, const float *persistence_map,
                        size_t bufsize);
 
};
 
float NoisePerlin2D(const NoiseParams *np, float x, float y, s32 seed);
float NoisePerlin3D(const NoiseParams *np, float x, float y, float z, s32 seed);
 
inline float NoisePerlin2D_PO(NoiseParams *np, float x, float xoff,
        float y, float yoff, s32 seed)
{
        return NoisePerlin2D(np,
                x + xoff * np->spread.X,
                y + yoff * np->spread.Y,
                seed);
}
 
inline float NoisePerlin3D_PO(NoiseParams *np, float x, float xoff,
        float y, float yoff, float z, float zoff, s32 seed)
{
        return NoisePerlin3D(np,
                x + xoff * np->spread.X,
                y + yoff * np->spread.Y,
                z + zoff * np->spread.Z,
                seed);
}
 
// Return value: -1 ... 1
float noise2d(int x, int y, s32 seed);
float noise3d(int x, int y, int z, s32 seed);
 
float noise2d_gradient(float x, float y, s32 seed, bool eased=true);
float noise3d_gradient(float x, float y, float z, s32 seed, bool eased=false);
 
float noise2d_perlin(float x, float y, s32 seed,
                int octaves, float persistence, bool eased=true);
 
inline float easeCurve(float t)
{
        return t * t * t * (t * (6.f * t - 15.f) + 10.f);
}
 
float contour(float v);