Function:ns2qsq

int ns2qsq(void);

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "s2plot.h"

#define CELLS 30

int id1;                                /* Global variable: isosurface id */

void cb(double *t, int *kc)
{
   char string[255];
   int isq = ns2qsq();                  /* Query the surface quality */
   sprintf(string,"Surface quality is: %d. Press <space> to toggle",isq);
   s2lab("","","",string);              /* Show a label on screen */
   ns2ssq(*kc%2);                       /* Set the surface quality */
   ns2dis(id1, 1);                      /* Display an isosurface */

}

int main(int argc, char *argv[])
{
   int i, j, k;                         /* Loop variables */
   float x, y, z;                       /* Dummy variables for grid values */
   int nx, ny, nz;                      /* Number of cells in grid */
   float ***grid;                       /* Grid data */
   float tr[12];                        /* Transformation matrix */
   int resolution;                      /* Resolution of isosurface */
   float level;                         /* Isosurface level to plot */
   float alpha;                         /* Alpha channel */
   char trans;                          /* Drawing mode for isosurface */

   nx = CELLS;                          /* Grid dimensions */
   ny = CELLS;
   nz = CELLS;

  /* Create transpose matrix mapping data indices to world coords */
   tr[0] = tr[4] = tr[8] = 0.0;                           /* Offsets */
   tr[1] = tr[6] = tr[11] = 1.0;                          /* Increments */
   tr[2] = tr[3] = tr[5] = tr[7] = tr[9] = tr[10] = 0.;   /* Cross terms */

   s2opend("/?",argc, argv);                    /* Open the display */
   s2swin(0, nx-1, 0, ny-1, 0, nz-1);           /* Set the window coordinates */
   s2box("BCDET",0,0,"BCDET",0,0,"BCDET",0,0);  /* Draw coordinate box */

   /* allocate and generate the data grid */
   grid = (float ***)malloc(nx * sizeof(float **));
   for (i = 0; i < nx; i++) {
      grid[i] = (float **)malloc(ny * sizeof(float *));
      x = (float)(i) / (float)(nx - 1);
      for (j = 0; j < ny; j++) {
         grid[i][j] = (float *)malloc(nz * sizeof(float));
         y = (float)(j) / (float)(ny - 1);
         for (k = 0; k < nz; k++) {
            z = (float)(k) / (float)(nz - 1);
            grid[i][j][k] = x*x*x + y*y - z*z*z*z;
         }
      }
   }
   level      = 0.2;                    /* Set the isosurface level */
   resolution = 1;                      /* Set the isosurface resolution */
   alpha      = 0.9;                    /* Set the alpha channel */
   trans      = 'o';                    /* Opaque isosurface */

/* Create the isosurface object */

   id1 = ns2cis(grid, nx, ny, nz, 0, nx-1, 0, ny-1, 0, nz-1,
                   tr, level, resolution, trans, alpha, 1., 1., 0.);

   cs2scb(cb);                          /* Install dynamic callback */

   s2show(1);                           /* Open the s2plot window */

   return 1;
}