Function:ns2vf3nca
From S2PLOT
ns2vf3nca
3-vertex facet with coloured vertices, normals and alpha per vertex given.
Prototype
void ns2vf3nca(XYZ *P, XYZ *N, COLOUR *col, char trans, float *alf);
Description
Complete control of 3-vertex facets is achieved with this function. Draws a 3-vertex facet with coloured vertices, with normals, and per vertex alpha transparency value for the facet. The vertices are given by the array P, normals are in the array N, and the RGB colours for vertices are in col. Transparency parameter trans is one of 'o' (opaque), 't' (addition blend - never gets dimmer) or 's' (standard blend, can get dimmer), and the alpha values in the range [0,1] are stored in array alf.
See Also
| ns2vf3 | 3-vertex facet with single colour and automatic normals. |
| ns2vf3n | 3-vertex facet with single colour and normals given. |
| ns2vf3c | 3-vertex facet with coloured vertices and autmoatic normals. |
| ns2vf3a | 3-vertex facet with transparency |
| struct_COLOUR | Data structure for (r,g,b) colour indices. |
| struct_XYZ | Data structure for (x,y,z) coordinates. |
Code Example
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "s2plot.h"
int main(int argc, char *argv[])
{
XYZ vertex[3]; /* 3 vertices */
XYZ normal[3]; /* 3 vertices */
float alpha[3]; /* 3 vertices */
COLOUR col[3]; /* 3 vertices */
char trans = 't'; /* Transparency type */
int i;
srand48((long)time(NULL)); /* Seed random numbers */
s2opend("/?",argc, argv); /* Open the display */
s2swin(-1.,1., -1.,1., -1.,1.); /* Set the window coordinates */
s2box("BCDET",0,0,"BCDET",0,0,"BCDET",0,0); /* Draw coordinate box */
for (i=0;i<3;i++) {
vertex[i].x = drand48()*2.0 - 1.0; /* Random corners to facet */
vertex[i].y = drand48()*2.0 - 1.0;
vertex[i].z = drand48()*2.0 - 1.0;
normal[i].x = drand48()*2.0 - 1.0; /* Random normal for facet */
normal[i].y = drand48()*2.0 - 1.0;
normal[i].z = drand48()*2.0 - 1.0;
col[i].r = drand48(); /* Random colour for vertex */
col[i].g = drand48();
col[i].b = drand48();
}
alpha[0] = 0.0; /* Set alpha channels for each */
alpha[1] = 0.5; /* vertex */
alpha[2] = 1.0;
ns2vf3nca(vertex, normal, col, trans, alpha);
/* Draw polygon with defined normals, vertex colours */
/* and vertex transparencies */
s2show(1); /* Open the s2plot window */
return 1;
}
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