/* Auteur: Nicolas JANEY                  */
/* Avril 2001                             */
/* Illustration des problemes d'affichage */
/* lies a l'algorithme de Gouraud         */

#include <windows.h>

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

static float anglex = 0.0F ;
static float angley = 0.0F ;
  
void initlights(void) { 
  GLfloat ambient[] = { 0.0F,0.0F,0.0F,1.0F }; 
  GLfloat diffuse[] = { 1.0F,0.7F,0.4F,1.0F }; 
  GLfloat spec[] = { 0.0F,0.0F,0.0F,1.0F }; 
  GLfloat shininess[] = { 0.0F }; 
  glEnable(GL_LIGHTING); 
  glEnable(GL_LIGHT0); 
  glLightfv(GL_LIGHT0,GL_AMBIENT,ambient); 
  glMaterialfv(GL_FRONT,GL_DIFFUSE,diffuse); 
  glMaterialfv(GL_FRONT,GL_SPECULAR,spec); 
  glMaterialfv(GL_FRONT,GL_SHININESS,shininess); 
} 
  
void CALLBACK display(void) { 
  GLfloat pos[] = { -1.0F,0.0F,1.0F,0.0F }; 
  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) ;
  glLightfv(GL_LIGHT0,GL_POSITION,pos); 
  glBegin(GL_QUAD_STRIP) ;
  glNormal3f(-0.707F,0.0F,0.707F) ;
  glVertex3f(-3.0F,2.0F,-1.0F) ;
  glVertex3f(-3.0F,-2.0F,-1.0F) ;
  glNormal3f(0.0F,0.0F,1.0F) ;
  glVertex3f(-2.0F,2.0F,1.0F) ;
  glVertex3f(-2.0F,-2.0F,1.0F) ;
  glVertex3f(-1.0F,2.0F,-1.0F) ;
  glVertex3f(-1.0F,-2.0F,-1.0F) ;
  glVertex3f(0.0F,2.0F,1.0F) ;
  glVertex3f(0.0F,-2.0F,1.0F) ;
  glVertex3f(1.0F,2.0F,-1.0F) ;
  glVertex3f(1.0F,-2.0F,-1.0F) ;
  glVertex3f(2.0F,2.0F,1.0F) ;
  glVertex3f(2.0F,-2.0F,1.0F) ;
  glNormal3f(0.707F,0.0F,0.707F) ;
  glVertex3f(3.0F,2.0F,-1.0F) ;
  glVertex3f(3.0F,-2.0F,-1.0F) ;
  glEnd() ;
  glPopMatrix(); 
  glFlush();
  auxSwapBuffers();
} 
  
void myinit(void) { 
  glClearColor(0.8F,0.8F,1.0F,1.0F); 
  glEnable(GL_DEPTH_TEST); 
  glEnable(GL_AUTO_NORMAL); 
  glEnable(GL_NORMALIZE); 
  initlights(); 
} 
  
void CALLBACK myReshape(int w,int h) { 
  glViewport(0,0,w,h); 
  glMatrixMode(GL_PROJECTION); 
  glLoadIdentity(); 
  if ( w <= h ) 
    glOrtho(-3.2,3.2,-3.2*(float)h/(float)w,3.2*(float)h/(float)w,-4.0,4.0); 
    else 
    glOrtho(-3.2*(float)w/(float)h,3.2*(float)w/(float)h,-3.2,3.2,-4.0,4.0); 
  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_RGB|AUX_DEPTH); 
  auxInitPosition(0,0,300,200); 
  auxInitWindow("Problème avec Gouraud"); 
  myinit(); 
  auxKeyFunc(AUX_UP,up) ;
  auxKeyFunc(AUX_DOWN,down) ;
  auxKeyFunc(AUX_LEFT,left) ;
  auxKeyFunc(AUX_RIGHT,right) ;
  auxReshapeFunc(myReshape); 
  auxMainLoop(display); 
}