#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<X11/Xlib.h>
#include<GL/gl.h>
#include<GL/glx.h>
#include<GL/glu.h>

Display                 *dpy;
Window                  root;
GLint                   att[] = { GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER, None };
XVisualInfo             *vi;
XSetWindowAttributes    swa;
Window                  win;
GLXContext              glc;
Pixmap			pixmap;
int			pixmap_width = 128, pixmap_height = 128;
GC			gc;
XImage			*xim;
GLuint			texture_id;

void Redraw() {
 XWindowAttributes	gwa;

 XGetWindowAttributes(dpy, win, &gwa);
 glViewport(0, 0, gwa.width, gwa.height);
 glClearColor(0.3, 0.3, 0.3, 1.0);
 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

 glMatrixMode(GL_PROJECTION);
 glLoadIdentity();
 glOrtho(-1.25, 1.25, -1.25, 1.25, 1., 20.);

 glMatrixMode(GL_MODELVIEW);
 glLoadIdentity();
 gluLookAt(0., 0., 10., 0., 0., 0., 0., 1., 0.);

 glColor3f(1.0, 1.0, 1.0);

 glBegin(GL_QUADS);
  glTexCoord2f(0.0, 0.0); glVertex3f(-1.0,  1.0, 0.0);
  glTexCoord2f(1.0, 0.0); glVertex3f( 1.0,  1.0, 0.0);
  glTexCoord2f(1.0, 1.0); glVertex3f( 1.0, -1.0, 0.0);
  glTexCoord2f(0.0, 1.0); glVertex3f(-1.0, -1.0, 0.0);
 glEnd(); 

 glXSwapBuffers(dpy, win); }

/*                */
/*  MAIN PROGRAM  */
/*                */
int main(int argc, char *argv[]) {
 XEvent		xev;

 dpy = XOpenDisplay(NULL);
 
 if(dpy == NULL) {
 	printf("\n\tcannot open display\n\n");
        exit(0); }
        
 root = DefaultRootWindow(dpy);
 
 vi = glXChooseVisual(dpy, 0, att);

 if(vi == NULL) {
 	printf("\n\tno appropriate visual found\n\n");
        exit(0); }
        
 swa.event_mask = ExposureMask | KeyPressMask;
 swa.colormap   = XCreateColormap(dpy, root, vi->visual, AllocNone);

 win = XCreateWindow(dpy, root, 0, 0, 600, 600, 0, vi->depth, InputOutput, vi->visual, CWEventMask  | CWColormap, &swa);
 XMapWindow(dpy, win);
 XStoreName(dpy, win, "PIXMAP TO TEXTURE");

 glc = glXCreateContext(dpy, vi, NULL, GL_TRUE);

 if(glc == NULL) {
	printf("\n\tcannot create gl context\n\n");
	exit(0); }

 glXMakeCurrent(dpy, win, glc);
 glEnable(GL_DEPTH_TEST);
 
 /* CREATE A PIXMAP AND DRAW SOMETHING */

 pixmap	= XCreatePixmap(dpy, root, pixmap_width, pixmap_height, vi->depth);
 gc = DefaultGC(dpy, 0);

 XSetForeground(dpy, gc, 0x00c0c0);
 XFillRectangle(dpy, pixmap, gc, 0, 0, pixmap_width, pixmap_height);

 XSetForeground(dpy, gc, 0x000000);
 XFillArc(dpy, pixmap, gc, 15, 25, 50, 50, 0, 360*64);

 XSetForeground(dpy, gc, 0x0000ff);
 XDrawString(dpy, pixmap, gc, 10, 15, "PIXMAP TO TEXTURE", strlen("PIXMAP TO TEXTURE"));

 XSetForeground(dpy, gc, 0xff0000);
 XFillRectangle(dpy, pixmap, gc, 75, 75, 45, 35);

 XFlush(dpy);
 xim = XGetImage(dpy, pixmap, 0, 0, pixmap_width, pixmap_height, AllPlanes, ZPixmap);

 if(xim == NULL) {
 	printf("\n\tximage could not be created.\n\n"); }

 /*	CREATE TEXTURE FROM PIXMAP */

 glEnable(GL_TEXTURE_2D);
 glGenTextures(1, &texture_id);
 glBindTexture(GL_TEXTURE_2D, texture_id);
 glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, pixmap_height, pixmap_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, (void*)(&(xim->data[0])));

 XDestroyImage(xim);
 
 while(1) {
 	XNextEvent(dpy, &xev);
        
        if(xev.type == Expose) {
        	Redraw(); }
                
	else if(xev.type == KeyPress) {
        	glXMakeCurrent(dpy, None, NULL);
 		glXDestroyContext(dpy, glc);
 		XDestroyWindow(dpy, win);
 		XCloseDisplay(dpy);
 		exit(0); } 
                
	} /* while(1) */
        
} /* int main(...) */