In order for this to work, your CSV file has to contain columns for both the
spatial position AND the vectors you want to visualize. It looks like the csv
file you are creating is actually only writing out the vector field. To get
this to work, your gen_sally function should fill a second array that simply
contains the x, y, and z variables on the inner loop. Then your create_csv
function should write a csv file with 6 columns. Three of them are for the
position coordinate I just described, and the other 3 are the vector that you
are currently writing.
-Ken
From: ParaView [mailto:paraview-boun...@public.kitware.com] On Behalf Of
GILLILAND G. (929919)
Sent: Wednesday, April 4, 2018 3:16 PM
To: paraview@public.kitware.com
Subject: [EXTERNAL] [Paraview] CSV Files and Volumetric Data
Hi there,
I have assignment where data is produced in C, and i have to export it to a
relevant file format that works with a visualisation software of my choice.
I've chosen Paraview, because i know that CSV files work with this software.
Rather than table to points, i want to be able to convert the points to a
volumetric dataset... So i can have greater control over colour mapping. But i
was told that the code that generates the dataset is missing some data, or i
may have missed something in the way i export the file.
I've included the code below; i would love some help with this. I'm only decent
with coding in Java and my lecturer has really given the class a lot of support.
Cheers
#include
#include
#include
#include
void gen_sally( int xs, int ys, int zs, int time, float *sally )
/*
* Gen_Sally creates a vector field of dimension [xs,ys,zs,3] from
* a proceedural function. By passing in different time arguements,
* a slightly different and rotating field is created.
*
* The magnitude of the vector field is highest at some funnel shape
* and values range from 0.0 to around 0.4 (I think).
*
* I just wrote these comments, 8 years after I wrote the function.
*
* Developed by Sally of Sally University
*
*/
{
float x, y, z;
int ix, iy, iz;
float r, xc, yc, scale, temp, z0;
float r2 = 8;
float SMALL = 0.001;
float xdelta = 1.0 / (xs-1.0);
float ydelta = 1.0 / (ys-1.0);
float zdelta = 1.0 / (zs-1.0);
for( iz = 0; iz < zs; iz++ )
{
z = iz * zdelta;// map z to 0->1
xc = 0.5 + 0.1*sin(0.04*time+10.0*z); // For each z-slice, determine the
spiral circle.
yc = 0.5 + 0.1*cos(0.03*time+3.0*z);//(xc,yc) determine the center of
the circle.
r = 0.1 + 0.4 * z*z + 0.1 * z * sin(8.0*z); // The radius also changes at each
z-slice.
r2 = 0.2 + 0.1*z; //r is the center radius, r2 is
for damping
for( iy = 0; iy < ys; iy++ )
{
y = iy * ydelta;
for( ix = 0; ix < xs; ix++ )
{
x = ix * xdelta;
temp = sqrt( (y-yc)*(y-yc) + (x-xc)*(x-xc) );
scale = fabs( r - temp );
/*
* I do not like this next line. It produces a discontinuity
* in the magnitude. Fix it later.
*
*/
if ( scale > r2 )
scale = 0.8 - scale;
else
scale = 1.0;
z0 = 0.1 * (0.1 - temp*z );
if ( z0 < 0.0 ) z0 = 0.0;
temp = sqrt( temp*temp + z0*z0 );
scale = (r + r2 - temp) * scale / (temp + SMALL);
scale = scale / (1+z);
*sally++ = scale * (y-yc) + 0.1*(x-xc);
*sally++ = scale * -(x-xc) + 0.1*(y-yc);
*sally++ = scale * z0;
}
}
}
}
void create_csv(char* filename,float *sally, int size){
printf("1");
printf("\n Creating %s.csv file",filename);
FILE *fp;
fp=fopen(filename,"w");
fprintf(fp,"X,Y,Z\n");
int i;
int counter = 0;
for(i = 0; i< size; i++){
if(sally[i] == 0){
fprintf(fp,"0");
}
else{
fprintf(fp,"%f",sally[i]);
}
counter++;
if(counter == 3){
fprintf(fp, "\n");
counter = 0;
}
else{
fprintf(fp,",");
}
}
fclose(fp);
printf("\n %sfile created",filename);
}
int main(int argc, char *argv[]){
printf("1\n");
//read from args
int xs;
int ys;
int zs;
int time;
sscanf(argv[1],"%d",);
sscanf(argv[2],"%d",);
sscanf(argv[3],"%d",);
sscanf(argv[4],"%d",);
int arraySize = xs*ys*zs*3;
//allocate memeory for array. This is done so that stack memory doesn't run
out.'
float* sally;
sally = (float*)malloc((arraySize) * sizeof(float));
//runs the code. One of the args is a pointer so no return type is needed.
gen_sally(xs,ys,zs,time,sally);
//create varibles for file generation
char filename[20] = "results.csv";
create_csv(filename, sally, arraySize);
free(sally);
return 0;
}
___
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