Relevant to Blender v2.31

#include "plugin.h"

/* Texture name */
char name[24]= "";

#define NR_TYPES 3
char stnames[NR_TYPES][16]= {"Intens","Color", "Bump"};
/* Structure for buttons,
 * butcode name default min max 0
 */

VarStruct varstr[]= {
 {NUM|FLO, "Const 1", 1.7, -1.0, 1.0, ""},
};


typedef struct Cast {
 float a;
} Cast;

float result[8];
float cfra;
int plugin_tex_doit(int, Cast*, float*, float*, float*);

/* Fixed Functions */
int plugin_tex_getversion(void) {
 return B_PLUGIN_VERSION;
}

void plugin_but_changed(int but) { }

void plugin_init(void) { }

void plugin_getinfo(PluginInfo *info) {
 info->name= name;
 info->stypes= NR_TYPES;
 info->nvars= sizeof(varstr)/sizeof(VarStruct);

 info->snames= stnames[0];
 info->result= result;
 info->cfra= &cfra;
 info->varstr= varstr;

 info->init= plugin_init;
 info->tex_doit= (TexDoit) plugin_tex_doit;
 info->callback= plugin_but_changed;
}

int plugin_tex_doit(int stype, Cast *cast, float *texvec, float *dxt,
 float *dyt) {

 if (stype == 1) {
 return 1;
 } if (stype == 2) {
 return 2;
 }
 return 0;
}