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Add support for the PCG32 PRNG algo (and associated script APIs)

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This commit is contained in:
kwolekr 2015-03-22 00:01:46 -04:00
parent 7679396ebb
commit 3993093f51
10 changed files with 415 additions and 179 deletions
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59
src/util/numeric.cpp
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@ -22,6 +22,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#include "log.h"
#include "../constants.h" // BS, MAP_BLOCKSIZE
#include "../noise.h" // PseudoRandom, PcgRandom
#include <string.h>
#include <iostream>
@ -115,36 +116,32 @@ void FacePositionCache::generateFacePosition(u16 d)
myrand
*/
static unsigned long next = 1;
PcgRandom g_pcgrand;
/* RAND_MAX assumed to be 32767 */
int myrand(void)
u32 myrand()
{
next = next * 1103515245 + 12345;
return((unsigned)(next/65536) % 32768);
return g_pcgrand.next();
}
void mysrand(unsigned seed)
void mysrand(unsigned int seed)
{
next = 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)
{
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;
return g_pcgrand.range(min, max);
}
// 64-bit unaligned version of MurmurHash
/*
64-bit unaligned version of MurmurHash
*/
u64 murmur_hash_64_ua(const void *key, int len, unsigned int seed)
{
const u64 m = 0xc6a4a7935bd1e995ULL;
@ -159,12 +156,12 @@ u64 murmur_hash_64_ua(const void *key, int len, unsigned int seed)
memcpy(&k, data, sizeof(u64));
data++;
k *= m;
k ^= k >> r;
k *= m;
k *= m;
k ^= k >> r;
k *= m;
h ^= k;
h *= m;
h *= m;
}
const unsigned char *data2 = (const unsigned char *)data;
@ -178,13 +175,13 @@ u64 murmur_hash_64_ua(const void *key, int len, unsigned int seed)
case 1: h ^= (u64)data2[0];
h *= m;
}
h ^= h >> r;
h *= m;
h ^= h >> r;
return h;
}
}
/*
@ -197,7 +194,7 @@ 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,
@ -213,7 +210,7 @@ bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir,
if(distance_ptr)
*distance_ptr = d;
// If block is far away, it's not in sight
if(d > range)
return false;
@ -221,7 +218,7 @@ bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir,
// Maximum radius of a block. The magic number is
// sqrt(3.0) / 2.0 in literal form.
f32 block_max_radius = 0.866025403784 * 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)
@ -242,7 +239,7 @@ bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f 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
if(cosangle < cos(camera_fov / 2))
return false;