#include <stdio.h>
#include <stdlib.h>
#include "s2plot.h"
unsigned int texid; /* 3D Texture ID */
void cb(double *t, int *kc)
{
int nverts = 4; /* Number of vertices in polygon */
char trans = 't'; /* 3d texture transparency */
float alpha = 0.7; /* Alpha channel value */
XYZ iP[4]; /* Array of polygon vertices */
XYZ iTC[4]; /* Array of texture coordinates */
static float texidx = 0.0; /* Current z-texture coordinate */
iP[0].x = iP[3].x = -1.0; /* Define polygon vertices */
iP[1].x = iP[2].x = +1.0;
iP[0].y = iP[1].y = +1.0;
iP[2].y = iP[3].y = -1.0;
iP[0].z = iP[1].z = iP[2].z = iP[3].z = texidx*2.0 - 1.0;
iTC[0].x = iTC[3].x = 0.0; /* Define texture coordinates */
iTC[1].x = iTC[2].x = 1.0;
iTC[0].y = iTC[1].y = 1.0;
iTC[2].y = iTC[3].y = 0.0;
iTC[0].z = iTC[1].z = iTC[2].z = iTC[3].z = texidx;
COLOUR col = { 1,1,1 }; /* Draw the polygon boundaries */
ns2vline(iP[0],iP[1],col);
ns2vline(iP[1],iP[2],col);
ns2vline(iP[2],iP[3],col);
ns2vline(iP[3],iP[0],col);
ns2texpoly3d(iP, iTC, nverts, texid, trans, alpha); /* Draw 3D texture */
texidx += (1.0/320.0); /* Choose next z-texture coordinate */
if (texidx > 1.0) texidx = 0.0;
}
int main(int argc, char *argv[])
{
int Nx = 32, Ny = 32, Nz = 32; /* Texture dimensions */
int w,h,d; /* Returned dimensions */
s2opend("/?",argc,argv); /* Open the s2plot display device */
s2swin(-1,1,-1,1,-1,1); /* Set the world coordinates */
s2box("BCDET",0,0,"BCDET",0,0,"BCDET",0,0);
texid = ss2c3dt(Nx, Ny, Nz); /* Create a new 3d texture */
unsigned char *bits = (unsigned char *)ss2g3dt(texid, &w, &h, &d);
/* Get the texture data for modification */
int i, j, k;
long idx;
float x,y,z;
for (i=0;i<Nx;i++) {
x = -1.0 + i*(2.0/(float)(Nx-1));
for (j=0;j<Ny;j++) {
y = -1.0 + j*(2.0/(float)(Ny-1));
for (k=0;k<Nz;k++) {
z = -1.0 + k*(2.0/(float)(Nz-1));
idx = ((i*Ny + j)*Nz + k)*4;
if ((x*x + y*y + z*z) < 1.0) { /* 3D solid red sphere */
bits[idx + 1 ] = 255;
ns2point(x,y,z,1,1,1); /* Plot point in sphere */
} else {
bits[idx + 0 ] = 0;
}
bits[idx + 1 ] = 0; /* Blue channel */
bits[idx + 2 ] = 0; /* Green channel */
bits[idx + 3 ] = 255; /* Alpha channel */
}
}
}
fprintf(stderr, "3d texture IS %d x %d x %d\n", w, h, d);
ss2pt(texid); /* Push back the texture */
cs2scb(cb); /* Install a dynamic callback */
s2show(1); /* Display the geometry */
return 0;
}
