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

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

#ifndef M_PI
#define M_PI 3.14159
#endif

static void cylindre(float r,float h,int n){
  float *cs =(float *) calloc(n,sizeof(float));
  float *sn =(float *) calloc(n,sizeof(float));
  int i;
  for( i = 0 ; i < n ; i++ ){
	  float a = (2*M_PI*i)/n;
	  sn[i] = sin(a);
	  cs[i] = cos(a); }
  glPushMatrix();
  glBegin(GL_QUAD_STRIP);
  for ( int j = 0 ; j < n ; j++ ) {
    float hi = h/2-(j*h/n);
    float hf = h/2-((j+1)*h/n);
    for( i = 0 ; i <= n ; i++ ){
      float x = r*cs[i%n];
      float z = -r*sn[i%n];
      glNormal3f(cs[i%n],0.0F,-sn[i%n]);
		  glVertex3f(x,hi,z);
		  glVertex3f(x,hf,z); } }
  glEnd();
  glBegin(GL_POLYGON);
  glNormal3f(0.0F,1.0F,0.0F);
  for ( i = 0 ; i < n ; i++ ){
	  float si = -sn[i];
	  float ci = cs[i];
    glVertex3f(r*ci,h/2,r*si); }
  glEnd();
  glBegin(GL_POLYGON);
  glNormal3f(0.0F,-1.0F,0.0F);
  for ( i = 0 ; i < n ; i++ ){
	  float si = sn[i];
	  float ci = cs[i];
    glVertex3f(r*ci,-h/2,r*si); }
  glEnd();
  free(cs);
  free(sn);
  glPopMatrix();
}

void cone(float r,float h,int n){
  float *cs =(float *) calloc(n,sizeof(float));
  float *sn =(float *) calloc(n,sizeof(float));
  int i;
  for ( i = 0 ; i < n ; i++ ) {
	  float a = (2*M_PI*i)/n;
	  sn[i] = sin(a);
	  cs[i] = cos(a); }
  glPushMatrix();
  float f = 1.0F/pow(r*r+h*h,0.5);
  for ( int j = 0 ; j < n ; j++ ) {
    glBegin(GL_QUAD_STRIP);
    for ( i = 0 ; i <= n ; i++ ) {
      float x = r*cs[i%n];
      float z = -r*sn[i%n];
      glNormal3f(cs[i%n]*f*h,r*f,-sn[i%n]*f*h);
		  glVertex3f(j*x/n,h/2-j*h/n,j*z/n);
		  glVertex3f((j+1)*x/n,h/2-(j+1)*h/n,(j+1)*z/n); }
    glEnd(); }
  glBegin(GL_POLYGON);
  glNormal3f(0.0F,-1.0F,0.0F);
  for ( i = 0 ; i < n ; i++ ) {
	  float si = sn[i];
	  float ci = cs[i];
    glVertex3f(r*ci,-h/2,r*si); }
  glEnd();
  free(cs);
  free(sn);
  glPopMatrix();
}

static void fleche(int fac) {
  glPushMatrix();
  glTranslatef(0.0F,1.5F,0.0);
  cylindre(0.5F,3.0F,fac);
  glTranslatef(0.0F,3.0F,0.0);
  cone(1.0F,3.0F,fac);
  glPopMatrix();
}

void croix(int fac) {
  glPushMatrix();
  fleche(fac);
  glRotatef(90.0F,0.0F,0.0F,1.0F);
  fleche(fac);
  glRotatef(90.0F,0.0F,0.0F,1.0F);
  fleche(fac);
  glRotatef(90.0F,0.0F,0.0F,1.0F);
  fleche(fac);
  glPopMatrix();
}