/* Auteur: Nicolas JANEY                */
/* Avril 2001                           */
/* Fonctions de dessin de cylindre      */

#include <windows.h>

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

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

static float anglex = 0.0F ;
static float angley = 0.0F ;
static int np = 40;

struct point3D {
  float x ;
  float y ;
  float z ; } ;

struct vecteur3D {
  float dx ;
  float dy ;
  float dz ; } ;

void cylindre(double r,double h) {
  point3D *tab =(point3D *) malloc(2*np*sizeof(point3D)) ;
  for ( int i = 0 ; i < np ; i++ ) {
    double a = 3.14159/np*2*i ;
    double cs = cos(a) ;
    double sn = sin(a) ;
    tab[i].x = tab[i+np].x =(float) (r*cs) ;
    tab[i].y =(float) (h/2.0) ;
    tab[i+np].y =(float) (-h/2.0) ;
    tab[i].z = tab[i+np].z =(float) (-r*sn) ; }
  glBegin(GL_POLYGON) ;
  for ( i = 0 ; i < np ; i++ ) {
    glVertex3fv((float *) &tab[i]) ; }
  glEnd() ;
  glBegin(GL_POLYGON) ;
  for ( i = 2*np-1 ; i >= np ; i-- ) {
    glVertex3fv((float *) &tab[i]) ; }
  glEnd() ;
  glBegin(GL_QUAD_STRIP) ;
  for ( i = 0 ; i <= np ; i++ ) {
    glVertex3fv((float *) &tab[i%np]);
    glVertex3fv((float *) &tab[(i%np)+np]); }
  glEnd() ;
  free(tab) ;
}

void cylindreAvecNormales(double r,double h) {
  float normale[3];
  glGetFloatv(GL_CURRENT_NORMAL,normale) ;
  point3D *tab =(point3D *) malloc(2*np*sizeof(point3D)) ;
  vecteur3D *norm =(vecteur3D *) malloc(np*sizeof(vecteur3D)) ;
  for ( int i = 0 ; i < np ; i++ ) {
    double a = 3.14159/np*2*i ;
    double cs = cos(a) ;
    double sn = sin(a) ;
    tab[i].x = tab[i+np].x =(float) (r*cs) ;
    tab[i].y =(float) (h/2.0) ;
    tab[i+np].y =(float) (-h/2.0) ;
    tab[i].z = tab[i+np].z =(float) (-r*sn) ;
    norm[i].dx =(float) cs ;
    norm[i].dy =(float) 0.0 ;
    norm[i].dz =(float) -sn ; }
  glBegin(GL_POLYGON) ;
  for ( i = 0 ; i < np ; i++ ) {
    glNormal3f(0.0f,1.0f,0.0f);
    glVertex3fv((float *) &tab[i]) ; }
  glEnd() ;
  glBegin(GL_POLYGON) ;
  for ( i = 2*np-1 ; i >= np ; i-- ) {
    glNormal3f(0.0f,-1.0f,0.0f);
    glVertex3fv((float *) &tab[i]) ; }
  glEnd() ;
  glBegin(GL_QUAD_STRIP) ;
  for ( i = 0 ; i <= np ; i++ ) {
    glNormal3fv((float *) &norm[i%np]);
    glVertex3fv((float *) &tab[i%np]);
    glVertex3fv((float *) &tab[(i%np)+np]); }
  glEnd() ;
  free(tab) ;
  free(norm) ;
  glNormal3fv(normale) ;
}

void CALLBACK display(void) {
  glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
  glPushMatrix();
  glRotatef(angley,0.0F,1.0F,0.0F) ;
  glRotatef(anglex,1.0F,0.0F,0.0F) ;
  glPushMatrix();
  float bleu[] = { 0.0F,0.0F,1.0F,1.0F };
  float jaune[] = { 1.0F,1.0F,0.0F,1.0F };
  glMaterialfv(GL_FRONT_AND_BACK,GL_DIFFUSE,bleu) ;
  glMaterialfv(GL_FRONT_AND_BACK,GL_SPECULAR,jaune) ;
  glMaterialf(GL_FRONT_AND_BACK,GL_SHININESS,90) ;
  glTranslatef(0.0F,0.65F,0.0F) ;
  glNormal3f(0.0f,0.0f,1.0f);
  cylindre(0.4,0.8) ;
  glPopMatrix();
  glPushMatrix();
  float rouge[] = { 1.0F,0.2F,0.2F,1.0F };
  glMaterialfv(GL_FRONT_AND_BACK,GL_DIFFUSE,rouge) ;
  glMaterialfv(GL_FRONT_AND_BACK,GL_SPECULAR,jaune) ;
  glMaterialf(GL_FRONT_AND_BACK,GL_SHININESS,90) ;
  glTranslatef(0.0F,-0.65F,0.0F) ;
  cylindreAvecNormales(0.4,0.8) ;
  glPopMatrix();
  glPopMatrix();
  glFlush();
  auxSwapBuffers();
}

void myinit (void) {
  glClearColor(0.5F,0.5F,0.5F,0.0F);
  glShadeModel(GL_SMOOTH);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  float jaune[] = { 0.6F,0.6F,0.0F,1.0F };
  glLightfv(GL_LIGHT0,GL_SPECULAR,jaune) ;
  glEnable(GL_CULL_FACE);
  glCullFace(GL_BACK);
}

void CALLBACK myReshape(int w, int h) {
  glViewport(0,0,w,h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glOrtho(-1.3,1.3,-1.3/w*h,1.3/w*h,-3.0,3.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

void CALLBACK up(void) {
  anglex++ ;
}

void CALLBACK down(void) {
  anglex-- ;
}

void CALLBACK left(void) {
  angley++ ;
}

void CALLBACK right(void) {
  angley-- ;
}

void main(void) {
  auxInitDisplayMode(AUX_DOUBLE|AUX_RGBA|AUX_DEPTH);
  auxInitPosition (0,0,300,300);
  auxInitWindow("Cylindre") ;
  myinit();
  auxKeyFunc(AUX_UP,up) ;
  auxKeyFunc(AUX_DOWN,down) ;
  auxKeyFunc(AUX_LEFT,left) ;
  auxKeyFunc(AUX_RIGHT,right) ;
  auxReshapeFunc(myReshape);
  auxMainLoop(display);
}