Function:ss2gt

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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 <time.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 */

   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 */

   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;
}

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Retrieved from "https://astronomy.swin.edu.au/s2plot/index.php?title=Function:ss2gt"
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