/* Copyright (c) Mark J. Kilgard, 1994. */

/**
 * (c) Copyright 1993, Silicon Graphics, Inc.
 * ALL RIGHTS RESERVED 
 * Permission to use, copy, modify, and distribute this software for 
 * any purpose and without fee is hereby granted, provided that the above
 * copyright notice appear in all copies and that both the copyright notice
 * and this permission notice appear in supporting documentation, and that 
 * the name of Silicon Graphics, Inc. not be used in advertising
 * or publicity pertaining to distribution of the software without specific,
 * written prior permission. 
 *
 * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
 * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
 * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
 * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
 * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
 * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
 * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
 * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
 * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
 * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
 * 
 * US Government Users Restricted Rights 
 * Use, duplication, or disclosure by the Government is subject to
 * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
 * (c)(1)(ii) of the Rights in Technical Data and Computer Software
 * clause at DFARS 252.227-7013 and/or in similar or successor
 * clauses in the FAR or the DOD or NASA FAR Supplement.
 * Unpublished-- rights reserved under the copyright laws of the
 * United States.  Contractor/manufacturer is Silicon Graphics,
 * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
 *
 * OpenGL(TM) is a trademark of Silicon Graphics, Inc.
 */
/*
 *  fog.c
 *  This program draws 5 red teapots, each at a different 
 *  z distance from the eye, in different types of fog.  
 *  Pressing the left mouse button chooses between 3 types of 
 *  fog:  exponential, exponential squared, and linear.  
 *  In this program, there is a fixed density value, as well 
 *  as fixed start and end values for the linear fog.
 */

#include "windows.h"

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

#include <stdio.h>

static GLint fogMode;
static float anglex = 0.0F ;
static float angley = 0.0F ;

void CALLBACK cycleFog(AUX_EVENTREC *event) {
  if(fogMode == GL_EXP) {
    fogMode = GL_EXP2;
    printf("Fog mode is GL_EXP2\n"); }
    else
    if(fogMode == GL_EXP2) {
      fogMode = GL_LINEAR;
      printf("Fog mode is GL_LINEAR\n");
      glFogf(GL_FOG_START,1.0);
      glFogf(GL_FOG_END,5.0); }
      else 
      if(fogMode == GL_LINEAR) {
        fogMode = GL_EXP;
        printf("Fog mode is GL_EXP\n"); }
  glFogi(GL_FOG_MODE,fogMode);
}

void myinit(void) {
  GLfloat position[] = { 0.0,3.0,3.0,0.0 };
  GLfloat local_view[] = { 0.0 };
  glEnable(GL_DEPTH_TEST);
  glDepthFunc(GL_LESS);
  glLightfv(GL_LIGHT0,GL_POSITION,position);
  glLightModelfv(GL_LIGHT_MODEL_LOCAL_VIEWER,local_view);
  glFrontFace(GL_CW);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glEnable(GL_AUTO_NORMAL);
  glEnable(GL_NORMALIZE);
  glEnable(GL_FOG);
  GLfloat fogColor[4] = {0.5,0.5,0.5,1.0};
  fogMode = GL_EXP;
  glFogi(GL_FOG_MODE,fogMode);
  glFogfv(GL_FOG_COLOR,fogColor);
  glFogf(GL_FOG_DENSITY,0.35F);
  glHint(GL_FOG_HINT,GL_DONT_CARE);
  glClearColor(0.5,0.5,0.5,1.0);
}

void renderRedTeapot(GLfloat x,GLfloat y,GLfloat z) {
  float mat[4];
  glPushMatrix();
  glTranslatef(x,y,z);
  mat[0] = 0.1745F;
  mat[1] = 0.01175F; 
  mat[2] = 0.01175F; 
  mat[3] = 1.0F;  
  glMaterialfv(GL_FRONT,GL_AMBIENT,mat);
  mat[0] = 0.61424F; 
  mat[1] = 0.04136F; 
  mat[2] = 0.04136F;  
  glMaterialfv(GL_FRONT,GL_DIFFUSE,mat);
  mat[0] = 0.727811F; 
  mat[1] = 0.626959F;
  mat[2] = 0.626959F;
  glMaterialfv(GL_FRONT,GL_SPECULAR,mat);
  glMaterialf(GL_FRONT,GL_SHININESS,0.6F*128.0F);
  glColor3f(1,1,1);
  auxSolidTeapot(1.0);
  glPopMatrix();
}

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) ;
  renderRedTeapot(-4.0,-0.5,-1.0);
  renderRedTeapot(-2.0,-0.5,-2.0);
  renderRedTeapot(0.0,-0.5,-3.0);
  renderRedTeapot(2.0,-0.5,-4.0);
  renderRedTeapot(4.0,-0.5,-5.0);
  glPopMatrix();
  glFlush();
  auxSwapBuffers() ;
}

void CALLBACK myReshape(int w,int h) {
  glViewport(0,0,w,h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  if ( w <=(h*3) )
    glOrtho(-6.0,6.0,-2.0*((GLfloat) h*3)/(GLfloat) w,2.0*((GLfloat) h*3)/(GLfloat) w,-10.0,10.0);
    else
    glOrtho(-6.0*(GLfloat) w/((GLfloat) h*3),6.0*(GLfloat) w/((GLfloat) h*3),-2.0,2.0,-10.0,10.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

void CALLBACK up(void) {
  anglex -= 2 ;
}

void CALLBACK down(void) {
  anglex += 2 ;
}

void CALLBACK left(void) {
  angley -= 2 ;
}

void CALLBACK right(void) {
  angley += 2 ;
}

void main(void) {
  auxInitDisplayMode(AUX_DOUBLE|AUX_RGB|AUX_DEPTH);
  auxInitPosition(0,0,450,150);
  auxInitWindow("Brouillard");
  myinit();
  auxMouseFunc(AUX_LEFTBUTTON,AUX_MOUSEDOWN,cycleFog);
  auxKeyFunc(AUX_UP,up) ;
  auxKeyFunc(AUX_DOWN,down) ;
  auxKeyFunc(AUX_LEFT,left) ;
  auxKeyFunc(AUX_RIGHT,right) ;
  auxReshapeFunc(myReshape);
  auxMainLoop(display);
}