/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Novembre 2007                                */
/* Une sphere texturee avec une image           */
/* de la terre                                  */

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

#include <GL/glut.h>
#include <GL/gl.h>
#include <GL/glu.h>

#include "ChargePngFile.h"
#include "ModuleSpheres.h"

/* Variables globales                           */

static int disc = 72;
static int texturage = 1;
static int sphere = 0;
static int mode = 1;
static float angle = 0.0F;

/* Variables globales de gestion                */
/* de l'interactivite clavier et souris         */

static int clic = 0;
static int mx;
static int my;
static float rx = 0.0F;
static float ry = 0.0F;

void init(void) {
  const GLfloat mat_shininess[] = { 100.0 };
  const GLfloat blanc[] = { 1.0,1.0,1.0,1.0 };
  int resx;
  int resy;
  GLubyte *image;
  glLightfv(GL_LIGHT0,GL_DIFFUSE,blanc);
  glMaterialfv(GL_FRONT,GL_DIFFUSE,blanc);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glEnable(GL_DEPTH_TEST);
  image = chargeImagePng("Terre-02048.png",&resx,&resy);
  if ( image ) { 
    glPixelStorei(GL_UNPACK_ALIGNMENT,1); 
    glTexImage2D(GL_TEXTURE_2D,0,3,
                 resx,resy,0,
                 GL_RGB,
                 GL_UNSIGNED_BYTE,
                 image); 
    glTexParameterf(GL_TEXTURE_2D,
                    GL_TEXTURE_WRAP_S,
                    GL_REPEAT); 
    glTexParameterf(GL_TEXTURE_2D,
                    GL_TEXTURE_WRAP_T,
                    GL_REPEAT ); 
    glTexParameterf(GL_TEXTURE_2D,
                    GL_TEXTURE_MAG_FILTER,
                    GL_NEAREST); 
    glTexParameterf(GL_TEXTURE_2D,
                    GL_TEXTURE_MIN_FILTER,
                    GL_NEAREST); 
    free(image); }
}

/* Scene dessinee                               */

void scene(void) {
  glPushMatrix();
  const GLfloat light0_position[] = { 1.0,0.0,0.0,0.0 };
  glLightfv(GL_LIGHT0,GL_POSITION,light0_position);
  glRotatef(-23.0F,0.0F,0.0F,1.0F);
  glRotatef(angle,0.0F,1.0F,0.0F);
  switch ( sphere ) {
    case 0 : glutSolidSphere(4.0,disc,disc);
             break;
    case 1 : mySolidSphere(4.0,disc,disc);
             break; }
  glPopMatrix();
}

/* Fonction executee lors d'un rafraichissement */
/* de la fenetre de dessin                      */

void display(void) {
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glPushMatrix();
  glPolygonMode(GL_FRONT,(mode) ? GL_FILL : GL_LINE);
  if ( texturage )
    glEnable(GL_TEXTURE_2D);
    else
    glDisable(GL_TEXTURE_2D);
  glRotatef(rx,1.0F,0.0F,0.0F);
  glRotatef(ry,0.0F,1.0F,0.0F);
  scene();
  glPopMatrix();
  glFlush();
  glutSwapBuffers();
  int error = glGetError();
  if ( error != GL_NO_ERROR )
    printf("Attention, erreur OpenGL %d\n",error);
}

/* Fonction executee lors d'un clic de souris   */
/* dans la fenetre                              */

void mouse(int bouton,int etat,int x,int y) {
  if ( bouton == GLUT_LEFT_BUTTON ) {
    if ( etat == GLUT_DOWN ) {
      clic = 1;
      mx = x;
      my = y; }
    if ( etat == GLUT_UP ) {
      clic = 0; } }
}

/* Fonction executee lors d'un deplacement      */
/* de la souris sur la fenetre                  */
/* avec un bouton appuye                        */

void motion(int x,int y) {
  if ( clic ) {
    ry += (x-mx);
    rx += (y-my);
    mx = x;
    my = y;
    glutPostRedisplay(); }
}

/* Fonction executee lors d'un changement       */
/* de la taille de la fenetre OpenGL            */

void reshape(int x,int y) {
  glViewport(0,0,x,y); 
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glOrtho(-5.0,5.0,(double) -5.0*y/x,(double) 5.0*y/x,-5.0,5.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

void idle(void) {
  angle += 0.5F;
  glutPostRedisplay();
}

/* Fonction executee lors de la frappe          */
/* d'une touche alphanumerique du clavier       */

void key(unsigned char key,int x,int y) {
  switch ( key ) {
    case 43   : disc++;
                glutPostRedisplay();
                break;
    case 45   : disc--;
                if ( disc < 1 )
                  disc = 1;
                glutPostRedisplay();
                break;
    case 'f'  : mode = !mode;
                glutPostRedisplay();
                break;
    case 0x20 : sphere = !sphere;
                glutPostRedisplay();
                break;
    case 0x0D : texturage = !texturage;
                glutPostRedisplay();
                break;
    case 'a'  : { static int anim = 1;
                  anim = !anim;
                  glutIdleFunc((anim) ? idle : NULL); }
                break;
    case 0x1B : exit(0);
                break; }
}

/* Fonction principale                          */

int main(int argc,char **argv) {
  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
  glutInitWindowSize(260,260); 
  glutInitWindowPosition(50,50); 
  glutCreateWindow("La terre"); 
  init();
  glutReshapeFunc(reshape);
  glutKeyboardFunc(key);
  glutMotionFunc(motion);
  glutMouseFunc(mouse);
  glutIdleFunc(idle);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}