perlin.c File Reference

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

#include "perlin.h"
#include "rng.h"

Include dependency graph for perlin.c:

Go to the source code of this file.

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

Macros
#define	SIMPLEX_SCALE   0.5f
#define	SWAP(a, b, t)
#define	FLOOR(a)
#define	NOISE_SIMPLEX_GRADIENT_1D(n, h, x)

Functions
perlin_data_t *	noise_new (void)
	Creates a new perlin noise generator.
float	noise_simplex1 (perlin_data_t *pdata, float f[1])
	Gets 1D simplex noise for a position.
void	noise_delete (perlin_data_t *pdata)
	Frees some noise data.

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

)

Value:

   ( (int)( a ) - ( ( a ) < 0 && ( a ) != (int)( a ) ) )

Limits to 0.

Definition at line 65 of file perlin.c.

NOISE_SIMPLEX_GRADIENT_1D

#define NOISE_SIMPLEX_GRADIENT_1D	(		n,
			h,
			x )

Value:

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

Definition at line 92 of file perlin.c.

SIMPLEX_SCALE

#define SIMPLEX_SCALE   0.5f

Definition at line 51 of file perlin.c.

SWAP

#define SWAP	(		a,
			b,
			t )

Value:

   ( t ) = ( a );                                                              \
   ( a ) = ( b );                                                              \
   ( b ) = ( t )

Swaps two values.

Definition at line 61 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 135 of file perlin.c.

noise_new()

perlin_data_t * noise_new

(

void

)

Creates a new perlin noise generator.

Definition at line 71 of file perlin.c.

noise_simplex1()

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

Gets 1D simplex noise for a position.

Parameters

pdata	Perlin data to generate noise from.
f	Position of the noise.

Definition at line 108 of file perlin.c.