SFA Project On-line Documentation: Vector and Noise routines

This file implements the vector and noise routines needed to generate the different shapes that are being used for the shape mappings in SFA. The vector routines are basic. A vector is typedef-ed to an array of 3 floats. This makes it compatible with the OpenGL vectors.

The noise functions are taken from the book :
Texturing and modeling - a procedural approach
David Ebert et al, A P Professional, 1994.

#ifndef _VECTOR_NOISE_H
#define _VECTOR_NOISE_H

//
// Vector.C  : The vector routines  
// Part of my code for CMSC 698
//
// Pradyut Panda

# include 
# include 

# include 
# include 
# include 


typedef float Pvector[3] ;

void vnormalize( Pvector v );
void vcross_product( Pvector v1 , Pvector v2, Pvector out );
void vminus( Pvector , Pvector , Pvector );


// -------------------------------------------------------------

/* noise.h : contains functions for noise , turbulence
   and fBm type functions 
*/

# define NOISE_SIZE 64
# define TRUE  1 
# define FALSE 0


typedef struct xyz_td {
  float    x,y,z;
} xyz_td;


/* the noise functions */
float calc_noise( xyz_td pnt);
float turbulence( xyz_td pnt , float pixel_size);
double fBm( xyz_td , double , double , double  );

# endif

    

Vector functions

• void vnormalize( Pvector v ) : Normalizes the vector v.
• void vcross_product( Pvector v1 , Pvector v2, Pvector out ) : Computes the normal vector cross product of vector v1 with vector v2 and stores the result in out.
• void vminus( Pvector A , Pvector B, Pvector temp) : subtracts vector A from vector b ( temp = A - B ) and stores result in temp. Useful for creating a vector from 2 points.

Noise functions

• float calc_noise( xyz_td pnt) : Returns a float between 0.0 and 1.0 depending on the value of pnt. The noise space is a grid of 64x64x64.
• float turbulence( xyz_td pnt , float pixel_size) : Returns the summation of noise over a few octaves at the point pnt.
• double fBm( xyz_td pnt, double H, double lacunarity, double octaves ) : Computes fractional Brownian motion for the point pnt.