/* Auteur: Nicolas JANEY        */
/* Avril 2001                   */
/* Programmation du calcul      */
/* d'une courbe de Bezier       */
/* pour dessiner un cercle!     */

#include <windows.h>

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

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

#include "modulefont.h"

static GLfloat view_rotx=0.0F ;
static GLfloat view_roty=0.0F ;
static GLfloat view_rotz=0.0F ;

static int n = 100 ;

float p = 0.55F ;
float pts1[4][3] = { {1.0F,0.0F,0.0F},
                     {1.0F,p,0.0F},
                     {p,1.0F,0.0F},
                     {0.0F,1.0F,0.0F} } ;

void traceCercle(float r) {
  glPushMatrix() ;
  glScalef(r,r,r) ;
  glColor3f(1.0,0.0,1.0);
  glBegin(GL_LINE_LOOP) ;
  for ( int i = 0 ; i < 360 ; i++ ) {
    float x =(float) cos(i*3.1459/180) ;
    float y =(float) sin(i*3.1459/180) ;
    glVertex2f(x,y) ; }
  glEnd() ;
  glPopMatrix() ;
}

void traceQuartCercleBezierGL(float r) {
  glPushMatrix() ;
  glScalef(r,r,r) ;
  glMap1f(GL_MAP1_VERTEX_3,
          0.0,1.0,3,4,&pts1[0][0]); 
  glEnable(GL_MAP1_VERTEX_3); 
  glColor3f(0.0,1.0,1.0);
  glBegin(GL_POINTS); 
  for ( int i = 0 ; i <= n ; i++ ) 
    glEvalCoord1f((GLfloat) i/100.0F); 
  glEnd(); 
  glPopMatrix() ;
}

void traceCercleBezierGL(float r) {
  glPushMatrix() ;
  traceQuartCercleBezierGL(r) ;
  glRotatef(90.0F,0.0F,0.0F,1.0F) ;
  traceQuartCercleBezierGL(r) ;
  glRotatef(90.0F,0.0F,0.0F,1.0F) ;
  traceQuartCercleBezierGL(r) ;
  glRotatef(90.0F,0.0F,0.0F,1.0F) ;
  traceQuartCercleBezierGL(r) ;
  glPopMatrix() ;
}

void CALLBACK display(void) { 
  glClear(GL_COLOR_BUFFER_BIT|
          GL_DEPTH_BUFFER_BIT); 
  glPushMatrix();
  glEnable(GL_DEPTH_TEST);
  glRotatef(view_rotx,1.0,0.0,0.0);
  glRotatef(view_roty,0.0,1.0,0.0);
  glRotatef(view_rotz,0.0,0.0,1.0);
  traceCercle(6.0F) ;
  traceCercleBezierGL(6.0F) ;
  glPopMatrix();
  glPushMatrix();
  glDisable(GL_DEPTH_TEST);
  glColor3f(1.0,1.0,0.0); 
  glRasterPos2f(-6.5,-6.5);
  char st[50] ;
  sprintf(st,"p = %5.2f",p);
  printString(st);
  glPopMatrix();
  glFlush();
  auxSwapBuffers();
} 

void CALLBACK myReshape(int w,int h) { 
  glViewport(0,0,w,h); 
  glMatrixMode(GL_PROJECTION); 
  glLoadIdentity(); 
  if( w <= h ) {
    float y = 7.F*(float)h/(float)w ;
    glOrtho(-7.,7.,-y,y,-7.,7.); }
    else  {
    float x = 7.F*(float)w/(float)h ;
    glOrtho(-x,x,-7.,7.,-7.,7.); }
  glMatrixMode(GL_MODELVIEW); 
  glLoadIdentity(); 
} 
  
void myinit(void) { 
  makeRasterFont();
  glClearColor(0.0,0.0,0.0,1.0); 
  glShadeModel(GL_FLAT); 
  glDepthFunc(GL_LESS);
} 
  
void CALLBACK keyRight(void) {
  p += 0.01F ;
  pts1[1][1] = p ;
  pts1[2][0] = p ;
}

void CALLBACK keyLeft(void) {
  p -= 0.01F ;
  pts1[1][1] = p ;
  pts1[2][0] = p ;
}

void CALLBACK keyx(void) {
  view_rotx += 2 ;
}

void CALLBACK keyX(void) {
  view_rotx -= 2 ;
}

void CALLBACK keyy(void) {
  view_roty += 2 ;
}

void CALLBACK keyY(void) {
  view_roty -= 2 ;
}

void CALLBACK keyz(void) {
  view_rotz += 2 ;
}

void CALLBACK keyZ(void) {
  view_rotz -= 2 ;
}

void main(void) { 
  auxInitDisplayMode(AUX_DOUBLE|AUX_RGBA|AUX_DEPTH); 
  auxInitPosition(0,0,300,300); 
  auxInitWindow("Courbe de Bezier"); 
  myinit(); 
  auxKeyFunc(AUX_x,keyx) ;
  auxKeyFunc(AUX_X,keyX) ;
  auxKeyFunc(AUX_y,keyy) ;
  auxKeyFunc(AUX_Y,keyY) ;
  auxKeyFunc(AUX_z,keyz) ;
  auxKeyFunc(AUX_Z,keyZ) ;
  auxKeyFunc(AUX_RIGHT,keyRight) ;
  auxKeyFunc(AUX_LEFT,keyLeft) ;
  auxReshapeFunc(myReshape); 
  auxMainLoop(display); 
}