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-rw-r--r--src/noise.h71
1 files changed, 46 insertions, 25 deletions
diff --git a/src/noise.h b/src/noise.h
index e59e73b23..d2287835e 100644
--- a/src/noise.h
+++ b/src/noise.h
@@ -30,47 +30,67 @@
#include "irr_v3d.h"
#include "util/string.h"
-#define PSEUDORANDOM_MAX 32767
-
extern FlagDesc flagdesc_noiseparams[];
-class PseudoRandom
-{
+// Note: this class is not polymorphic so that its high level of
+// optimizability may be preserved in the common use case
+class PseudoRandom {
public:
- PseudoRandom(): m_next(0)
- {
- }
- PseudoRandom(int seed): m_next(seed)
+ const static u32 RANDOM_RANGE = 32767;
+
+ inline PseudoRandom(int seed=0):
+ m_next(seed)
{
}
- void seed(int seed)
+
+ inline void seed(int seed)
{
m_next = seed;
}
- // Returns 0...PSEUDORANDOM_MAX
- int next()
+
+ inline int next()
{
m_next = m_next * 1103515245 + 12345;
- return((unsigned)(m_next/65536) % (PSEUDORANDOM_MAX + 1));
+ return (unsigned)(m_next / 65536) % (RANDOM_RANGE + 1);
}
- int range(int min, int max)
+
+ inline int range(int min, int max)
{
- if (max-min > (PSEUDORANDOM_MAX + 1) / 10)
- {
- //dstream<<"WARNING: PseudoRandom::range: max > 32767"<<std::endl;
- assert("Something wrong with random number" == NULL);
- }
- if(min > max)
- {
- assert("Something wrong with random number" == NULL);
- //return max;
- }
- return (next()%(max-min+1))+min;
+ assert(max >= min);
+ /*
+ Here, we ensure the range is not too large relative to RANDOM_MAX,
+ as otherwise the effects of bias would become noticable. Unlike
+ PcgRandom, we cannot modify this RNG's range as it would change the
+ output of this RNG for reverse compatibility.
+ */
+ assert((u32)(max - min) <= (RANDOM_RANGE + 1) / 10);
+
+ return (next() % (max - min + 1)) + min;
}
+
private:
int 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);
+
+private:
+ u64 m_state;
+ u64 m_inc;
+};
+
#define NOISE_FLAG_DEFAULTS 0x01
#define NOISE_FLAG_EASED 0x02
#define NOISE_FLAG_ABSVALUE 0x04
@@ -89,7 +109,8 @@ struct NoiseParams {
float lacunarity;
u32 flags;
- NoiseParams() {
+ NoiseParams()
+ {
offset = 0.0f;
scale = 1.0f;
spread = v3f(250, 250, 250);