/*

 * 3x3 matrix versions of Paul Haeberli's code from

 *

 *   "Matrix Operations for Image Processing", November 1993.

 *

 *  See:

 *    http://www.sgi.com/grafica/matrix/index.html

 *    http://www.sgi.com/grafica/matrix/matrix.c

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*/

#include <stdio.h>

#include <math.h>

#include <GLUT/glut.h>

/* Some <math.h> files do not define M_PI... */

#ifndef M_PI

#define M_PI 3.14159265358979323846

#endif

#include "mat3x3.h"

#define RLUM    (0.3086)

#define GLUM    (0.6094)

#define BLUM    (0.0820)

/* 

 *      printmat -      

 *              print a 3 by 3 matrix

 */

void

printmat3(float mat[3][3])

{

    int x, y;

    fprintf(stderr,"\n");

    for(y=0; y<3; y++) {

        for(x=0; x<3; x++) 

           fprintf(stderr,"%f ",mat[y][x]);

        fprintf(stderr,"\n");

    }

    fprintf(stderr,"\n");

}

/* 

 *      matrixmult3 -    

 *              multiply two 3x3 matricies

 */

void

matrixmult3(float a[3][3], float b[3][3], float c[3][3])

{

    int x, y;

    float temp[3][3];

    for(y=0; y<3 ; y++)

        for(x=0 ; x<3 ; x++) {

            temp[y][x] = b[y][0] * a[0][x]

                       + b[y][1] * a[1][x]

                       + b[y][2] * a[2][x];

        }

    for(y=0; y<3; y++)

        for(x=0; x<3; x++)

            c[y][x] = temp[y][x];

}

/* 

 *      identmat3 -      

 *              make an identity 3x3 matrix

 */

void

identmat3(float matrix[3][3])

{

    matrix[0][0] = 1.0;    /* row 1        */

    matrix[0][1] = 0.0;

    matrix[0][2] = 0.0;

    matrix[1][0] = 0.0;    /* row 2        */

    matrix[1][1] = 1.0;

    matrix[1][2] = 0.0;

    matrix[2][0] = 0.0;    /* row 3        */

    matrix[2][1] = 0.0;

    matrix[2][2] = 1.0;

}

/* 

 *      xformpnt3 -      

 *              transform a 3D point using a 3x3 matrix

 */

void

xformpnt3(float matrix[3][3], float x, float y, float z,

          float *tx, float *ty, float *tz)

{

    *tx = x*matrix[0][0] + y*matrix[1][0] + z*matrix[2][0];

    *ty = x*matrix[0][1] + y*matrix[1][1] + z*matrix[2][1];

    *tz = x*matrix[0][2] + y*matrix[1][2] + z*matrix[2][2];

}

/* 

 *      cscalemat3 -     

 *              make a color scale 3x3 matrix

 */

void

cscalemat3(float mat[3][3], float rscale, float gscale, float bscale)

{

    float mmat[3][3];

    mmat[0][0] = rscale;

    mmat[0][1] = 0.0;

    mmat[0][2] = 0.0;

    mmat[1][0] = 0.0;

    mmat[1][1] = gscale;

    mmat[1][2] = 0.0;

    mmat[2][0] = 0.0;

    mmat[2][1] = 0.0;

    mmat[2][2] = bscale;

    matrixmult3(mmat,mat,mat);

}

/* 

 *      lummat3 -        

 *              make a luminance 3x3 matrix

 */

void

lummat3(float mat[3][3])

{

    float mmat[3][3];

    float rwgt, gwgt, bwgt;

    rwgt = RLUM;

    gwgt = GLUM;

    bwgt = BLUM;

    mmat[0][0] = rwgt;

    mmat[0][1] = rwgt;

    mmat[0][2] = rwgt;

    mmat[1][0] = gwgt;

    mmat[1][1] = gwgt;

    mmat[1][2] = gwgt;

    mmat[2][0] = bwgt;

    mmat[2][1] = bwgt;

    mmat[2][2] = bwgt;

    matrixmult3(mmat,mat,mat);

}

/* 

 *      saturatemat3 -   

 *              make a saturation 3x3 matrix

 */

void

saturatemat3(float mat[3][3], float sat)

{

    float mmat[3][3];

    float a, b, c, d, e, f, g, h, i;

    float rwgt, gwgt, bwgt;

    rwgt = RLUM;

    gwgt = GLUM;

    bwgt = BLUM;

    a = (1.0-sat)*rwgt + sat;

    b = (1.0-sat)*rwgt;

    c = (1.0-sat)*rwgt;

    d = (1.0-sat)*gwgt;

    e = (1.0-sat)*gwgt + sat;

    f = (1.0-sat)*gwgt;

    g = (1.0-sat)*bwgt;

    h = (1.0-sat)*bwgt;

    i = (1.0-sat)*bwgt + sat;

    mmat[0][0] = a;

    mmat[0][1] = b;

    mmat[0][2] = c;

    mmat[1][0] = d;

    mmat[1][1] = e;

    mmat[1][2] = f;

    mmat[2][0] = g;

    mmat[2][1] = h;

    mmat[2][2] = i;

    matrixmult3(mmat,mat,mat);

}

/* 

 *      xrotate3 -       

 *              rotate about the x (red) axis

 */

void

xrotatemat3(float mat[3][3], float rs, float rc)

{

    float mmat[3][3];

    mmat[0][0] = 1.0;

    mmat[0][1] = 0.0;

    mmat[0][2] = 0.0;

    mmat[1][0] = 0.0;

    mmat[1][1] = rc;

    mmat[1][2] = rs;

    mmat[2][0] = 0.0;

    mmat[2][1] = -rs;

    mmat[2][2] = rc;

    matrixmult3(mmat,mat,mat);

}

/* 

 *      yrotate -       

 *              rotate about the y (green) axis

 */

void

yrotatemat3(float mat[3][3], float rs, float rc)

{

    float mmat[3][3];

    mmat[0][0] = rc;

    mmat[0][1] = 0.0;

    mmat[0][2] = -rs;

    mmat[1][0] = 0.0;

    mmat[1][1] = 1.0;

    mmat[1][2] = 0.0;

    mmat[2][0] = rs;

    mmat[2][1] = 0.0;

    mmat[2][2] = rc;

    matrixmult3(mmat,mat,mat);

}

/* 

 *      zrotate3 -       

 *              rotate about the z (blue) axis

 */

void

zrotatemat3(float mat[3][3], float rs, float rc)

{

    float mmat[3][3];

    mmat[0][0] = rc;

    mmat[0][1] = rs;

    mmat[0][2] = 0.0;

    mmat[1][0] = -rs;

    mmat[1][1] = rc;

    mmat[1][2] = 0.0;

    mmat[2][0] = 0.0;

    mmat[2][1] = 0.0;

    mmat[2][2] = 1.0;

    matrixmult3(mmat,mat,mat);

}

/* 

 *      zshear3 -        

 *              shear z using x and y.

 */

void

zshearmat3(float mat[3][3], float dx, float dy)

{

    float mmat[3][3];

    mmat[0][0] = 1.0;

    mmat[0][1] = 0.0;

    mmat[0][2] = dx;

    mmat[1][0] = 0.0;

    mmat[1][1] = 1.0;

    mmat[1][2] = dy;

    mmat[2][0] = 0.0;

    mmat[2][1] = 0.0;

    mmat[2][2] = 1.0;

    matrixmult3(mmat,mat,mat);

}

/* 

 *      simplehuerotatemat -    

 *              simple hue rotation. This changes luminance 

 */

void

simplehuerotatemat3(float mat[3][3], float rot)

{

    float mag;

    float xrs, xrc;

    float yrs, yrc;

    float zrs, zrc;

/* rotate the grey vector into positive Z */

    mag = sqrt(2.0);

    xrs = 1.0/mag;

    xrc = 1.0/mag;

    xrotatemat3(mat,xrs,xrc);

    mag = sqrt(3.0);

    yrs = -1.0/mag;

    yrc = sqrt(2.0)/mag;

    yrotatemat3(mat,yrs,yrc);

/* rotate the hue */

    zrs = sin(rot*M_PI/180.0);

    zrc = cos(rot*M_PI/180.0);

    zrotatemat3(mat,zrs,zrc);

/* rotate the grey vector back into place */

    yrotatemat3(mat,-yrs,yrc);

    xrotatemat3(mat,-xrs,xrc);

}

/* 

 *      huerotatemat -  

 *              rotate the hue, while maintaining luminance.

 */

void

huerotatemat3(float mat[3][3], float rot)

{

    float mmat[3][3];

    float mag;

    float lx, ly, lz;

    float xrs, xrc;

    float yrs, yrc;

    float zrs, zrc;

    float zsx, zsy;

    identmat3(mmat);

/* rotate the grey vector into positive Z */

    mag = sqrt(2.0);

    xrs = 1.0/mag;

    xrc = 1.0/mag;

    xrotatemat3(mmat,xrs,xrc);

    mag = sqrt(3.0);

    yrs = -1.0/mag;

    yrc = sqrt(2.0)/mag;

    yrotatemat3(mmat,yrs,yrc);

/* shear the space to make the luminance plane horizontal */

    xformpnt3(mmat,RLUM,GLUM,BLUM,&lx,&ly,&lz);

    zsx = lx/lz;

    zsy = ly/lz;

    zshearmat3(mmat,zsx,zsy);

/* rotate the hue */

    zrs = sin(rot*M_PI/180.0);

    zrc = cos(rot*M_PI/180.0);

    zrotatemat3(mmat,zrs,zrc);

/* unshear the space to put the luminance plane back */

    zshearmat3(mmat,-zsx,-zsy);

/* rotate the grey vector back into place */

    yrotatemat3(mmat,-yrs,yrc);

    xrotatemat3(mmat,-xrs,xrc);

    matrixmult3(mmat,mat,mat);

}