/* Auteur: Nicolas JANEY                  */
/* Avril 2001                             */
/* Illustration du clipping 3D en OpenGL  */

#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 clip = 0 ;

void CALLBACK display(void) {
  double equ0[] = { 1.1,1.2,0.9,0.8 } ;
  double equ1[] = { -1.3,1.8,1.5,2.5 } ;
  glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
  glPushMatrix();
  glPushMatrix();
  glRotatef(angley,0.0F,1.0F,0.0F) ;
  glRotatef(anglex,1.0F,0.0F,0.0F) ;
  glClipPlane(GL_CLIP_PLANE0,equ0);
  glClipPlane(GL_CLIP_PLANE1,equ1);
  glPopMatrix();
  auxSolidSphere(8.0);
  glPopMatrix();
  glFlush();
  auxSwapBuffers();
}

void myinit (void) {
  glLightModeli(GL_LIGHT_MODEL_TWO_SIDE,1);
  GLfloat specularFront[] = { 1.0,1.0,1.0,1.0 };
  GLfloat shininesFront[] = { 50.0 };
  glClearColor(0.5,0.5,1.0,1.0) ;
  glMaterialfv(GL_FRONT,GL_SPECULAR,specularFront);
  glMaterialfv(GL_FRONT,GL_SHININESS,shininesFront);
  GLfloat specularBack[] = { 1.0,1.0,1.0,1.0 };
  GLfloat diffuseBack[] = { 1.0,0.0,0.0,1.0 };
  GLfloat shininesBack[] = { 50.0 };
  glMaterialfv(GL_BACK,GL_SPECULAR,specularBack);
  glMaterialfv(GL_BACK,GL_SHININESS,shininesBack);
  glMaterialfv(GL_BACK,GL_DIFFUSE,diffuseBack);
  GLfloat l_pos0[] = { 1.0,1.0,1.0,0.0 };
  glLightfv(GL_LIGHT0,GL_POSITION,l_pos0);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
  glShadeModel(GL_SMOOTH);
  glEnable(GL_CLIP_PLANE0);
  glEnable(GL_CLIP_PLANE1);
}

void CALLBACK myReshape(int w, int h) {
  glViewport(0,0,w,h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glOrtho(-10,10,-10/(double) w*h,10/(double) w*h,-10.0,10.0);
  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 CALLBACK space(void) {
  clip = 1 - clip ;
}

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