OpenGLUT 0.6.3 development - OpenGLUT: dof.c File Reference
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# dof.c File Reference

## Detailed Description

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.

    /* 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     * Unpublished-- rights reserved under the copyright laws of the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.
     */

    #include <GL/openglut.h>
    #include <stdlib.h>
    #include <math.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. */
    }

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