/*
 * License Applicability. Except to the extent portions of this file are
 * made subject to an alternative license as permitted in the SGI Free
 * Software License B, Version 1.1 (the "License"), the contents of this
 * file are subject only to the provisions of the License. You may not use
 * this file except in compliance with the License. You may obtain a copy
 * of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
 * Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
 * 
 * http://oss.sgi.com/projects/FreeB
 * 
 * Note that, as provided in the License, the Software is distributed on an
 * "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
 * DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
 * CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
 * PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
 * 
 * Original Code. The Original Code is: OpenGL Sample Implementation,
 * Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
 * Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
 * Copyright in any portions created by third parties is as indicated
 * elsewhere herein. All Rights Reserved.
 * 
 * Additional Notice Provisions: The application programming interfaces
 * established by SGI in conjunction with the Original Code are The
 * OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
 * April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
 * 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
 * Window System(R) (Version 1.3), released October 19, 1998. This software
 * was created using the OpenGL(R) version 1.2.1 Sample Implementation
 * published by SGI, but has not been independently verified as being
 * compliant with the OpenGL(R) version 1.2.1 Specification.
 *
 */

/*
 *  alpha3D.c
 *  This program demonstrates how to intermix opaque and
 *  alpha blended polygons in the same scene, by using 
 *  glDepthMask.  Press the 'a' key to animate moving the 
 *  transparent object through the opaque object.  Press 
 *  the 'r' key to reset the scene.
 */
#include <stdlib.h>
#include <stdio.h>
#include "ug.h"

#define MAXZ 8.0
#define MINZ -8.0
#define ZINC 0.4

static float solidZ = MAXZ;
static float transparentZ = MINZ;

static void init(void)
{
   GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 0.15 };
   GLfloat mat_shininess[] = { 100.0 };
   GLfloat position[] = { 0.5, 0.5, 1.0, 0.0 };

   glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, mat_specular);
   glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, mat_shininess);
   glLightfv(GL_LIGHT0, GL_POSITION, position);

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

static void display(UGWindow uwin)
{
   GLfloat mat_solid[] = { 0.75, 0.75, 0.0, 1.0 };
   GLfloat mat_zero[] = { 0.0, 0.0, 0.0, 1.0 };
   GLfloat mat_transparent[] = { 0.0, 0.8, 0.8, 0.6 };
   GLfloat mat_emission[] = { 0.0, 0.3, 0.3, 0.6 };

   glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

   glPushMatrix ();
      glTranslatef (-0.15, -0.15, solidZ);
      glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, mat_zero);
      glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, mat_solid);
      ugSolidSpheref(0.4, 32, 32);
   glPopMatrix ();

   glPushMatrix ();
      glTranslatef (0.15, 0.15, transparentZ);
      glRotatef (15.0, 1.0, 1.0, 0.0);
      glRotatef (30.0, 0.0, 1.0, 0.0);
      glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, mat_emission);
      glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, mat_transparent);
      glEnable (GL_BLEND);
      glDepthMask (GL_FALSE);
	  glBlendFunc (GL_SRC_ALPHA, GL_ONE);
      ugSolidCubef(0.6);
	  glDepthMask (GL_TRUE);
      glDisable (GL_BLEND);
   glPopMatrix ();

   ugSwapBuffers(uwin);
}

static void reshape(UGWindow uwin, int w, int h)
{
   glViewport(0, 0, (GLint) w, (GLint) h);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   if (w <= h)
      glOrthof(-1.5, 1.5, -1.5*(GLfloat)h/(GLfloat)w,
               1.5*(GLfloat)h/(GLfloat)w, -10.0, 10.0);
   else
      glOrthof(-1.5*(GLfloat)w/(GLfloat)h,
               1.5*(GLfloat)w/(GLfloat)h, -1.5, 1.5, -10.0, 10.0);
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
}

static void animate(UGWindow uwin)
{
   if (solidZ <= MINZ || transparentZ >= MAXZ)
      ugIdleFunc(ugCtxFromWin(uwin), NULL);
   else {
      solidZ -= ZINC;
      transparentZ += ZINC;
      ugPostRedisplay(uwin);
   }
}

static void keyboard(UGWindow uwin, int key, int x, int y)
{
   switch (key) {
      case 'a':
      case 'A':
         solidZ = MAXZ;
         transparentZ = MINZ;
         ugIdleFunc(ugCtxFromWin(uwin), animate);
         break;
      case 'r':
      case 'R':
         solidZ = MAXZ;
         transparentZ = MINZ;
         ugPostRedisplay(uwin);
         break;
      case 27:
        exit(0);
    }
}

#ifdef FTK_AS_PLUGIN
#include "ftk_app_demo.h"
FTK_HIDE int FTK_MAIN(int argc, char* argv[]);
FtkApp* ftk_app_demo_alpha3D_create()
{
	return ftk_app_demo_create(_("alpha3D"), ftk_main);
}
#else
#define FTK_HIDE extern
#endif /*FTK_AS_PLUGIN*/

FTK_HIDE int FTK_MAIN(int argc, char* argv[])
{
   UGCtx ug = ugInit();
   UGWindow uwin = ugCreateWindow (ug, "", "alpha3D", 500, 500, 100, 100);
   init();
   ugDisplayFunc(uwin, display); 
   ugReshapeFunc(uwin, reshape);
   ugKeyboardFunc(uwin, keyboard);
   ugIdleFunc(ugCtxFromWin(uwin), animate);

#ifndef FTK_AS_PLUGIN
   ugMainLoop(ug);
#endif

   return 0;
}