www.pudn.com > openglbk.rar > accpersp.c

/* 
 * Copyright (c) 1993-1999, Silicon Graphics, Inc. 
 * ALL RIGHTS RESERVED  
 * Permission to use, copy, modify, and distribute this software for  
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 * the name of Silicon Graphics, Inc. not be used in advertising 
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 * written prior permission.  
 * 
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 * 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, 
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 *  
 * 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 * Unpublished-- rights reserved under the copyright laws of the 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. 
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 * OpenGL(R) is a registered trademark of Silicon Graphics, Inc. 
 */ 
 
/*  accpersp.c 
 *  Use the accumulation buffer to do full-scene antialiasing 
 *  on a scene with perspective projection, using the special 
 *  routines accFrustum() and accPerspective(). 
 */ 
#include  
#include  
#include  
#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 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); 
} 
 
/*  Initialize lighting and other values. 
 */ 
void init(void) 
{ 
   GLfloat mat_ambient[] = { 1.0, 1.0, 1.0, 1.0 }; 
   GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 }; 
   GLfloat light_position[] = { 0.0, 0.0, 10.0, 1.0 }; 
   GLfloat lm_ambient[] = { 0.2, 0.2, 0.2, 1.0 }; 
 
   glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient); 
   glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular); 
   glMaterialf(GL_FRONT, GL_SHININESS, 50.0); 
   glLightfv(GL_LIGHT0, GL_POSITION, light_position); 
   glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lm_ambient); 
     
   glEnable(GL_LIGHTING); 
   glEnable(GL_LIGHT0); 
   glEnable(GL_DEPTH_TEST); 
   glShadeModel (GL_FLAT); 
 
   glClearColor(0.0, 0.0, 0.0, 0.0); 
   glClearAccum(0.0, 0.0, 0.0, 0.0); 
} 
 
void displayObjects(void)  
{ 
   GLfloat torus_diffuse[] = { 0.7, 0.7, 0.0, 1.0 }; 
   GLfloat cube_diffuse[] = { 0.0, 0.7, 0.7, 1.0 }; 
   GLfloat sphere_diffuse[] = { 0.7, 0.0, 0.7, 1.0 }; 
   GLfloat octa_diffuse[] = { 0.7, 0.4, 0.4, 1.0 }; 
     
   glPushMatrix (); 
   glTranslatef (0.0, 0.0, -5.0);  
   glRotatef (30.0, 1.0, 0.0, 0.0); 
 
   glPushMatrix (); 
   glTranslatef (-0.80, 0.35, 0.0);  
   glRotatef (100.0, 1.0, 0.0, 0.0); 
   glMaterialfv(GL_FRONT, GL_DIFFUSE, torus_diffuse); 
   glutSolidTorus (0.275, 0.85, 16, 16); 
   glPopMatrix (); 
 
   glPushMatrix (); 
   glTranslatef (-0.75, -0.50, 0.0);  
   glRotatef (45.0, 0.0, 0.0, 1.0); 
   glRotatef (45.0, 1.0, 0.0, 0.0); 
   glMaterialfv(GL_FRONT, GL_DIFFUSE, cube_diffuse); 
   glutSolidCube (1.5); 
   glPopMatrix (); 
 
   glPushMatrix (); 
   glTranslatef (0.75, 0.60, 0.0);  
   glRotatef (30.0, 1.0, 0.0, 0.0); 
   glMaterialfv(GL_FRONT, GL_DIFFUSE, sphere_diffuse); 
   glutSolidSphere (1.0, 16, 16); 
   glPopMatrix (); 
 
   glPushMatrix (); 
   glTranslatef (0.70, -0.90, 0.25);  
   glMaterialfv(GL_FRONT, GL_DIFFUSE, octa_diffuse); 
   glutSolidOctahedron (); 
   glPopMatrix (); 
 
   glPopMatrix (); 
} 
 
#define ACSIZE	8 
 
void display(void) 
{ 
   GLint viewport[4]; 
   int jitter; 
 
   glGetIntegerv (GL_VIEWPORT, viewport); 
 
   glClear(GL_ACCUM_BUFFER_BIT); 
   for (jitter = 0; jitter < ACSIZE; jitter++) { 
      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
      accPerspective (50.0,  
         (GLdouble) viewport[2]/(GLdouble) viewport[3],  
         1.0, 15.0, j8[jitter].x, j8[jitter].y, 0.0, 0.0, 1.0); 
      displayObjects (); 
      glAccum(GL_ACCUM, 1.0/ACSIZE); 
   } 
   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 (250, 250); 
   glutInitWindowPosition (100, 100); 
   glutCreateWindow (argv[0]); 
   init(); 
   glutReshapeFunc(reshape); 
   glutDisplayFunc(display); 
   glutKeyboardFunc(keyboard); 
   glutMainLoop(); 
   return 0; 
}