dof.c

OpenGL学习资料

/*
 * Copyright (c) 1993-1999, 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
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 * 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 * Unpublished-- rights reserved under the copyright laws of the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(R) is a registered 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 <GL/glut.h>
#include <stdlib.h>
#include <math.h>
#include "jitter.h"

#define PI_ 3.14159265358979323846

GLuint teapotList;

/* 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 zNear, GLdouble zFar, 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*zNear/focus);
   dy = -(pixdy*ywsize/(GLdouble) viewport[3] + eyedy*zNear/focus);
	
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glFrustum (left + dx, right + dx, bottom + dy, top + dy, zNear, zFar);
   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 zNear, GLdouble zFar, GLdouble pixdx, GLdouble pixdy, 
   GLdouble eyedx, GLdouble eyedy, GLdouble focus)
{
   GLdouble fov2,left,right,bottom,top;

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

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

   right = top * aspect;
   left = -right;

   accFrustum (left, right, bottom, top, zNear, zFar,
               pixdx, pixdy, eyedx, eyedy, focus);
}

void init(void)
{
   GLfloat ambient[] = { 0.0, 0.0, 0.0, 1.0 };
   GLfloat diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
   GLfloat specular[] = { 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 };

   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);
   glEnable(GL_DEPTH_TEST);

   glClearColor(0.0, 0.0, 0.0, 0.0);
   glClearAccum(0.0, 0.0, 0.0, 0.0); 
/*  make teapot display list */
   teapotList = glGenLists(1);
   glNewList (teapotList, GL_COMPILE);
   glutSolidTeapot (0.5);
   glEndList ();
}

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)
{
   GLfloat 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);
   glCallList(teapotList);
   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 reshape(int w, int h)
{
   glViewport(0, 0, (GLsizei) w, (GLsizei) h);
}

void keyboard(unsigned char key, int x, int y)
{
   switch (key) {
      case 27:
         exit(0);
         break;
   }
}

/*  Main Loop
 *  Be certain you request an accumulation buffer.
 */
int main(int argc, char** argv)
{
   glutInit(&argc, argv);
   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB
			| GLUT_ACCUM | GLUT_DEPTH); 
   glutInitWindowSize (400, 400);
   glutInitWindowPosition (100, 100);
   glutCreateWindow (argv[0]);
   init();
   glutReshapeFunc(reshape);
   glutDisplayFunc(display);
   glutKeyboardFunc(keyboard);
   glutMainLoop();
   return 0;
}