/*
 * (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 * Unpublished-- rights reserved under the copyright laws of the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.
 */
/*
 *  alpha3D.c
 *  This program demonstrates how to intermix opaque and
 *  alpha blended polygons in the same scene, by using glDepthMask.
 *  Pressing the left mouse button toggles the eye position.
 */
#include <GL/gl.h>
#include <GL/glu.h>
#include <stdlib.h>
#include <GL/glaux.h>

void myinit(void)
{
  GLfloat mat_ambient[] =
  {0.0, 0.0, 0.0, 0.15};
  GLfloat mat_specular[] =
  {1.0, 1.0, 1.0, 0.15};
  GLfloat mat_shininess[] =
  {15.0};

  glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);
  glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
  glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);

  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
}

GLboolean eyePosition = GL_FALSE;

void toggleEye(AUX_EVENTREC * event)
{
  if (eyePosition)
    eyePosition = GL_FALSE;
  else
    eyePosition = GL_TRUE;
}

void display(void)
{
  GLfloat position[] =
  {0.0, 0.0, 1.0, 1.0};
  GLfloat mat_torus[] =
  {0.75, 0.75, 0.0, 1.0};
  GLfloat mat_cylinder[] =
  {0.0, 0.75, 0.75, 0.15};

  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glLightfv(GL_LIGHT0, GL_POSITION, position);
  glPushMatrix();
  if (eyePosition)
    gluLookAt(0.0, 0.0, 9.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
  else
    gluLookAt(0.0, 0.0, -9.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
  glPushMatrix();
  glTranslatef(0.0, 0.0, 1.0);
  glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_torus);
  auxSolidTorus(0.275, 0.85);
  glPopMatrix();

  glEnable(GL_BLEND);
  glDepthMask(GL_FALSE);
  glBlendFunc(GL_SRC_ALPHA, GL_ONE);
  glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_cylinder);
  glTranslatef(0.0, 0.0, -1.0);
  auxSolidCylinder(1.0, 2.0);
  glDepthMask(GL_TRUE);
  glDisable(GL_BLEND);
  glPopMatrix();

  glFlush();
}

void myReshape(int w, int h)
{
  glViewport(0, 0, w, h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(30.0, (GLfloat) w / (GLfloat) h, 1.0, 20.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

/*
 * Main Loop
 * *  Open window with initial window size, title bar, 
 * *  RGBA display mode, and handle input events.
 */
int main(int argc, char **argv)
{
  auxInitDisplayMode(AUX_SINGLE | AUX_RGB | AUX_DEPTH);
  auxInitPosition(0, 0, 500, 500);
  if (!auxInitWindow(argv[0]))
    auxQuit();
  auxMouseFunc(AUX_LEFTBUTTON, AUX_MOUSEDOWN, toggleEye);
  myinit();
  auxReshapeFunc(myReshape);
  auxMainLoop(display);
  return 0;
}