#include <stdio.h>
#include <stdlib.h>
#include <glut.h>

/*
 * skel.c: OpenGL skeleton program
 *
 * 1/03 pjf
 *
 * written mainly to show the various callbacks
 *
 * doesn't do any 3D stuff
 *
 */

/* display callback */
void display() {
 fprintf(stderr,"display.\n");
 glClear(GL_COLOR_BUFFER_BIT);
 glColor3f(drand48(),drand48(),drand48()); /* pick a random color */
 glRectf(-1.0,-1.0,1.0,1.0);
 glFlush();
 }


/* idle callback: called whenever nothing else is happening. */
/* note: printf commented out because this is called a lot. */
void idle(void) {
 // fprintf(stderr,"idle.\n"); 
 }

/* mouse: called when a mouse button is pressed or released.
   btn identifies which button; state identifies "press" or "release" */
void mouse(int btn, int state, int x, int y) {
 fprintf(stderr,"mouse: btn %d, state %d, location (%d,%d).\n",btn,state,x,y);
 }

/* called initially (before first call to display()) and whenever the
   window is resized */
void reshape(int w, int h) {
  fprintf(stderr,"reshape: new size %d x %d.\n",w,h);
  // must update viewport and clipping planes
  glViewport(0, 0, w, h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  if (w <= h)
      glOrtho(-2.0, 2.0, -2.0 * (GLfloat) h / (GLfloat) w,
              2.0 * (GLfloat) h / (GLfloat) w, -10.0, 10.0);
  else
      glOrtho(-2.0 * (GLfloat) w / (GLfloat) h,
              2.0 * (GLfloat) w / (GLfloat) h, -2.0, 2.0, -10.0, 10.0);
  glMatrixMode(GL_MODELVIEW);
}

void ticktimer(int value) {
 fprintf(stderr,"tick (%d)\n",value);
 }

void tocktimer(int value) {
 fprintf(stderr,"tock (%d)\n",value);
 }

void visibility(int state) {
 fprintf(stderr,"Visibility now %d.\n",state);
 }
 
void special(int key,int x,int y) {
 fprintf(stderr,"Special: key %d, loc (%d %d).\n",key,x,y);
 }
 
void motion(int x, int y) {
 fprintf(stderr,"Motion: loc (%d %d).\n",x,y);
 }
 
/* note: commented out because this is called a lot */
void passivemotion(int x, int y) {
 fprintf(stderr,"Passive Motion: loc (%d %d).\n",x,y);
 }
 
void keyboard(int key,int x,int y) {
 fprintf(stderr,"Keyboard: key %d, loc (%d %d).\n",key,x,y);
 }
 
void entry(int state) {
 fprintf(stderr,"Entry: state %d.\n",state);
 }
 
void init(void) {
 /* nothing to do! */
 }

int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB);
    glutInitWindowSize(500, 500);
    glutCreateWindow(argv[0]);
    glutReshapeFunc(reshape);
    glutDisplayFunc(display);
    glutIdleFunc(idle);
    glutMouseFunc(mouse);
    glutTimerFunc(1000,ticktimer,1963);
    glutTimerFunc(2000,tocktimer,20012);
    glutVisibilityFunc(visibility);
    glutSpecialFunc(special);
    glutMotionFunc(motion);
    glutPassiveMotionFunc(passivemotion);
    glutKeyboardFunc(keyboard);
    glutEntryFunc(entry);
    init();
    glutMainLoop();
    return 0;
}