Function:ss2gt
From S2PLOT
(Difference between revisions)
Revision as of 23:02, 28 October 2007
ss2gt
Get a pointer to an identified texture.
Prototype
char *ss2gt(unsigned int textureID, int *width, int *height);
Description
Get a pointer to an identified texture. The return value of the function is a (char *), which points to a chunk of memory which is 4 * width * height bytes. A 4-byte segment of this memory contains r, g, b and a (alpha / transparency) values [0,255]. If the texture is not found, NULL is returned.
See Also
| Textures | Important information on using textures in S2PLOT. |
| ss2lt | Load a texture for future (generally repeated) use. |
| ss2pt | Reinstall a texture. |
Code Example
#include <stdio.h>
#include <stdlib.h>
#include "s2plot.h"
int main(int argc, char *argv[])
{
char *texture = "firetile2_pow2_rgb.tga";
/* Texture in directory pointed to by S2PLOT_TEXPATH */
int texid; /* ID for this texture */
char *tex; /* Array holding texture */
int width, height; /* Dimensions of texture */
int i, j; /* Loop variables */
int idx; /* Temporary index into array */
XYZ xyz = { 0.0, 0.0, 0.0 }; /* Location of sphere */
float r = 0.3; /* Radius of sphere */
COLOUR col = { 1.0, 1.0, 1.0 }; /* Colour of sphere */
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 */
texid = ss2lt(texture); /* Get an ID for texture */
tex = ss2gt(texid, &width, &height); /* Store texture */
for (j=0;j<(height/2);j++) { /* Bottom half of texture */
for (i=0;i<width;i++) {
idx = (j*width + i)*4; /* Stored as (r, g, b, alpha) */
tex[idx ] = 127*drand48()+128; /* Randomish Red */
tex[idx+1] = 0; /* Green */
tex[idx+2] = 0; /* Blue */
/* Do nothing to alpha */
}
}
ss2pt(texid); /* Restore texture for use */
ns2vspherex(xyz, r, col, texid); /* Draw textured sphere */
s2show(1); /* Open the s2plot window */
return 1;
}
Back to S2PLOT function list.
