
/* 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 * Unpublished-- rights reserved under the copyright laws of the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.
 */
/*
 *  dof.c
 *  This program demonstrates use of the accumulation buffer to
 *  create an out-of-focus depth-of-field effect.  The teapots
 *  are drawn several times into the accumulation buffer.  The
 *  viewing volume is jittered, except at the focal point, where
 *  the viewing volume is at the same position, each time.  In
 *  this case, the gold teapot remains in focus.
 */
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>
#include "jitter.h"

#define PI_ 3.14159265358979323846

/*	accFrustum()
 *  The first 6 arguments are identical to the glFrustum() call.
 *
 *  pixdx and pixdy are anti-alias jitter in pixels.
 *  Set both equal to 0.0 for no anti-alias jitter.
 *  eyedx and eyedy are depth-of field jitter in pixels.
 *  Set both equal to 0.0 for no depth of field effects.
 *
 *  focus is distance from eye to plane in focus.
 *  focus must be greater than, but not equal to 0.0.
 *
 *  Note that accFrustum() calls glTranslatef().  You will
 *  probably want to insure that your ModelView matrix has been
 *  initialized to identity before calling accFrustum().
 */
void accFrustum(GLdouble left, GLdouble right, GLdouble bottom,
    GLdouble top, GLdouble nnear, GLdouble ffar, GLdouble pixdx,
    GLdouble pixdy, GLdouble eyedx, GLdouble eyedy, GLdouble focus)
{
    GLdouble xwsize, ywsize;
    GLdouble dx, dy;
    GLint viewport[4];

    glGetIntegerv (GL_VIEWPORT, viewport);

    xwsize = right - left;
    ywsize = top - bottom;

    dx = -(pixdx*xwsize/(GLdouble) viewport[2] + eyedx*nnear/focus);
    dy = -(pixdy*ywsize/(GLdouble) viewport[3] + eyedy*nnear/focus);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glFrustum (left + dx, right + dx, bottom + dy, top + dy, nnear, ffar);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef (-eyedx, -eyedy, 0.0);
}

/*  accPerspective()
 *
 *  The first 4 arguments are identical to the gluPerspective() call.
 *  pixdx and pixdy are anti-alias jitter in pixels.
 *  Set both equal to 0.0 for no anti-alias jitter.
 *  eyedx and eyedy are depth-of field jitter in pixels.
 *  Set both equal to 0.0 for no depth of field effects.
 *
 *  focus is distance from eye to plane in focus.
 *  focus must be greater than, but not equal to 0.0.
 *
 *  Note that accPerspective() calls accFrustum().
 */
void accPerspective(GLdouble fovy, GLdouble aspect,
    GLdouble nnear, GLdouble ffar, GLdouble pixdx, GLdouble pixdy,
    GLdouble eyedx, GLdouble eyedy, GLdouble focus)
{
    GLdouble fov2,left,right,bottom,top;

    fov2 = ((fovy*PI_) / 180.0) / 2.0;

    top = nnear / (cos(fov2) / sin(fov2));
    bottom = -top;

    right = top * aspect;
    left = -right;

    accFrustum (left, right, bottom, top, nnear, ffar,
	pixdx, pixdy, eyedx, eyedy, focus);
}

void myinit(void)
{
    GLfloat ambient[] = { 0.0, 0.0, 0.0, 1.0 };
    GLfloat diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
    GLfloat position[] = { 0.0, 3.0, 3.0, 0.0 };

    GLfloat lmodel_ambient[] = { 0.2, 0.2, 0.2, 1.0 };
    GLfloat local_view[] = { 0.0 };

    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
    glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
    glLightfv(GL_LIGHT0, GL_POSITION, position);

    glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
    glLightModelfv(GL_LIGHT_MODEL_LOCAL_VIEWER, local_view);

    glFrontFace (GL_CW);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_AUTO_NORMAL);
    glEnable(GL_NORMALIZE);

    glMatrixMode (GL_MODELVIEW);
    glLoadIdentity ();

    glClearColor(0.0, 0.0, 0.0, 0.0);
    glClearAccum(0.0, 0.0, 0.0, 0.0);
}

void renderTeapot (GLfloat x, GLfloat y, GLfloat z,
    GLfloat ambr, GLfloat ambg, GLfloat ambb,
    GLfloat difr, GLfloat difg, GLfloat difb,
    GLfloat specr, GLfloat specg, GLfloat specb, GLfloat shine)
{
    float mat[4];

    glPushMatrix();
    glTranslatef (x, y, z);
    mat[0] = ambr; mat[1] = ambg; mat[2] = ambb; mat[3] = 1.0;
    glMaterialfv (GL_FRONT, GL_AMBIENT, mat);
    mat[0] = difr; mat[1] = difg; mat[2] = difb;
    glMaterialfv (GL_FRONT, GL_DIFFUSE, mat);
    mat[0] = specr; mat[1] = specg; mat[2] = specb;
    glMaterialfv (GL_FRONT, GL_SPECULAR, mat);
    glMaterialf (GL_FRONT, GL_SHININESS, shine*128.0);
    glutSolidTeapot(0.5);
    glPopMatrix();
}

/*  display() draws 5 teapots into the accumulation buffer
 *  several times; each time with a jittered perspective.
 *  The focal point is at z = 5.0, so the gold teapot will
 *  stay in focus.  The amount of jitter is adjusted by the
 *  magnitude of the accPerspective() jitter; in this example, 0.33.
 *  In this example, the teapots are drawn 8 times.  See jitter.h
 */
void display(void)
{
    int jitter;
    GLint viewport[4];

    glGetIntegerv (GL_VIEWPORT, viewport);
    glClear(GL_ACCUM_BUFFER_BIT);

    for (jitter = 0; jitter < 8; jitter++) {
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	accPerspective (45.0,
		(GLdouble) viewport[2]/(GLdouble) viewport[3],
		1.0, 15.0, 0.0, 0.0,
		0.33*j8[jitter].x, 0.33*j8[jitter].y, 5.0);
/*	ruby, gold, silver, emerald, and cyan teapots	*/
	renderTeapot (-1.1, -0.5, -4.5, 0.1745, 0.01175, 0.01175,
	    0.61424, 0.04136, 0.04136, 0.727811, 0.626959, 0.626959, 0.6);
	renderTeapot (-0.5, -0.5, -5.0, 0.24725, 0.1995, 0.0745,
	    0.75164, 0.60648, 0.22648, 0.628281, 0.555802, 0.366065, 0.4);
	renderTeapot (0.2, -0.5, -5.5, 0.19225, 0.19225, 0.19225,
	    0.50754, 0.50754, 0.50754, 0.508273, 0.508273, 0.508273, 0.4);
	renderTeapot (1.0, -0.5, -6.0, 0.0215, 0.1745, 0.0215,
	    0.07568, 0.61424, 0.07568, 0.633, 0.727811, 0.633, 0.6);
	renderTeapot (1.8, -0.5, -6.5, 0.0, 0.1, 0.06, 0.0, 0.50980392,
	    0.50980392, 0.50196078, 0.50196078, 0.50196078, .25);
	glAccum (GL_ACCUM, 0.125);
    }

    glAccum (GL_RETURN, 1.0);
    glFlush();
}

void myReshape(int w, int h)
{
    glViewport(0, 0, w, h);
}

static void
key(unsigned char k, int x, int y)
{
  switch (k) {
  case 27:  /* Escape */
    exit(0);
    break;
  default:
    return;
  }
  glutPostRedisplay();
}

/*  Main Loop
 *  Open window with initial window size, title bar,
 *  RGBA display mode, depth buffer, and handle input events.
 */
int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB
			| GLUT_ACCUM | GLUT_DEPTH);
    glutCreateWindow (argv[0]);
    myinit();
    glutReshapeFunc(myReshape);
    glutDisplayFunc(display);
    glutKeyboardFunc(key);
    glutMainLoop();
    return 0;             /* ANSI C requires main to return int. */
}
