/* Auteur: Nicolas JANEY                   */
/* nicolas.janey@univ-fcomte.fr            */
/* Septembre 2005                          */
/* Gestion minimum d'une camera            */

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

#include <math.h>
#include <stdio.h>

static int mode = 0;

void myinit(void) {
  GLfloat shinines[] = { 50.0 };
  GLfloat blanc[] = { 1.0,1.0,1.0,1.0 };
  glClearColor(0.5F,0.5F,1.0F,1.0F) ;
  glMaterialfv(GL_FRONT,GL_SPECULAR,blanc);
  glMaterialfv(GL_FRONT,GL_SHININESS,shinines);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glEnable(GL_AUTO_NORMAL);
  glEnable(GL_NORMALIZE);
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
}

void aileDroite(float a1,float a2) {
  glPushMatrix();
  glTranslatef(0.75F,0.0F,0.0F);
  glRotatef(a1,0.0F,0.0F,1.0F);
  glTranslatef(1.0F,0.0F,0.0F);
  glPushMatrix();
  glScalef(2.0F,0.1F,0.5F);
  glutSolidSphere(1.0,18,18);
  glPopMatrix();
  glTranslatef(2.0F,0.0F,0.0F);
  glRotatef(a2,0.0F,0.0F,1.0F);
  glTranslatef(0.9F,0.0F,0.0F);
  glPushMatrix();
  glScalef(1.0F,0.1F,0.5F);
  glutSolidSphere(1.0,18,18);
  glPopMatrix();
  glPopMatrix();
}

void aileGauche(float a1,float a2) {
  glPushMatrix();
  glTranslatef(-0.75F,0.0F,0.0F);
  glRotatef(-a1,0.0F,0.0F,1.0F);
  glTranslatef(-1.0F,0.0F,0.0F);
  glPushMatrix();
  glScalef(2.0F,0.1F,0.5F);
  glutSolidSphere(1.0,18,18);
  glPopMatrix();
  glTranslatef(-2.0F,0.0F,0.0F);
  glRotatef(-a2,0.0F,0.0F,1.0F);
  glTranslatef(-0.9F,0.0F,0.0F);
  glPushMatrix();
  glScalef(1.0F,0.1F,0.5F);
  glutSolidSphere(1.0,18,18);
  glPopMatrix();
  glPopMatrix();
}

void mouette() {
  static int image = 0;
  float a1 =(float) 25.0*cos((image*5)/180.0F);
  float a2 =(float) -40.0*cos(((image*5)+90)/180.0F);
  GLfloat l_pos[] = { 1.0,1.0,1.0,0.0 };
  glLightfv(GL_LIGHT0,GL_POSITION,l_pos);
  glPushMatrix();
  glTranslatef(0.0F,-a1/100.0F,0.0F);
  glPushMatrix();
  glScalef(0.75F,0.5F,1.5F);
  glutSolidSphere(1.0,18,18);
  glPopMatrix();
  aileDroite(a1,a2);
  aileGauche(a1,a2);
  glPopMatrix();
  image++;
}

void display(void) {
  glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
  glPolygonMode(GL_FRONT_AND_BACK,(mode) ? GL_LINE : GL_FILL);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glOrtho(-6.0F,6.0F,-3.0F,3.0F,-2.0F,9.0F);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  glTranslatef(0.0F,0.0F,-3.0F);
  glPushMatrix();
  mouette();
  glPopMatrix();
  glFlush();
  glutSwapBuffers();
  int error = glGetError();
  if ( error != GL_NO_ERROR )
    printf("Attention, erreur OpenGL %d\n",error);
}

void key(unsigned char key,int x,int y) {
  switch ( key ) {
    case 0x0D : glutPostRedisplay();
                break;
    case ' '  : mode = !mode;
                glutPostRedisplay();
                break; }
}

int main(int argc,char **argv) {
  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
  glutInitWindowSize(400,200); 
  glutInitWindowPosition(50,50); 
  glutCreateWindow("Gestion caméra minimum"); 
  myinit(); 
  glutKeyboardFunc(key);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}