Handles creating noise based on perlin noise. More...

#include "perlin.h"
#include "log.h"
#include "nfile.h"
#include "nstring.h"
#include "rng.h"

Data Structures
struct	perlin_data_t
	Structure used for generating noise. More...

Macros
#define	SIMPLEX_SCALE 0.5f

#define	SWAP(a, b, t) (t) = (a); (a) = (b); (b) = (t)

#define	FLOOR(a) ((int)(a) - ((a) < 0 && (a) != (int)(a)))

#define	NOISE_SIMPLEX_GRADIENT_1D(n, h, x) { float grad; h &= 0xF; grad=1.0f+(h & 7); if ( h & 8 ) grad = -grad; n = grad * x; }

Functions
perlin_data_t *	noise_new (void)
	Creates a new perlin noise generator. More...

float	noise_simplex1 (perlin_data_t *pdata, float f[1])
	Gets 1D simplex noise for a position. More...

void	noise_delete (perlin_data_t *pdata)
	Frees some noise data. More...

Detailed Description

Handles creating noise based on perlin noise.

Code tries to handle basically 2d/3d cases, without much genericness because it needs to be pretty fast. Originally sped up the code from about 20 seconds to 8 seconds per Nebula image with the manual loop unrolling.

Note: Tried to optimize a while back with SSE and the works, but because of the nature of how it's implemented in non-linear fashion it just wound up complicating the code without actually making it faster.

Definition in file perlin.c.

Macro Definition Documentation

◆ FLOOR

#define FLOOR ( a ) ((int)(a) - ((a) < 0 && (a) != (int)(a)))

Limits to 0.

Definition at line 71 of file perlin.c.

◆ NOISE_SIMPLEX_GRADIENT_1D

#define NOISE_SIMPLEX_GRADIENT_1D	(	n,
		h,
		x
	)	{ float grad; h &= 0xF; grad=1.0f+(h & 7); if ( h & 8 ) grad = -grad; n = grad * x; }

Definition at line 97 of file perlin.c.

◆ SIMPLEX_SCALE

#define SIMPLEX_SCALE 0.5f

Definition at line 60 of file perlin.c.

◆ SWAP

#define SWAP	(	a,
		b,
		t
	)	(t) = (a); (a) = (b); (b) = (t)

Swaps two values.

Definition at line 70 of file perlin.c.

Function Documentation

◆ noise_delete()

void noise_delete ( perlin_data_t * pdata )

Frees some noise data.

Parameters

pdata Noise data to free.

Definition at line 132 of file perlin.c.

◆ noise_new()

perlin_data_t * noise_new ( void )

Creates a new perlin noise generator.

Definition at line 76 of file perlin.c.

◆ noise_simplex1()

float noise_simplex1	(	perlin_data_t *	pdata,
		float	f[1]
	)

Gets 1D simplex noise for a position.