ACCPERSP.C

/* 
* (c) Copyright 1993, Silicon Graphics, Inc.
* 1993-1995 Microsoft Corporation
*
* ALL RIGHTS RESERVED
*
* Please refer to OpenGL/readme.txt for additional information
*
*/

/* accpersp.c
*/
#include "glos.h"

#include <GL/gl.h>
#include <GL/glu.h>
#include <math.h>
#include <GL/glaux.h>
#include "jitter.h"

void myinit(void);
void accFrustum(GLdouble left, GLdouble right, GLdouble bottom, GLdouble top,
GLdouble znear, GLdouble zfar, GLdouble pixdx, GLdouble pixdy,
GLdouble eyedx, GLdouble eyedy, GLdouble focus);
void accPerspective(GLdouble fovy, GLdouble aspect,
GLdouble znear, GLdouble zfar, GLdouble pixdx, GLdouble pixdy,
GLdouble eyedx, GLdouble eyedy, GLdouble focus);
void displayObjects(void);
void CALLBACK myReshape(GLsizei w, GLsizei h);
void CALLBACK display(void);


#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 myinit(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);
glDepthFunc(GL_LESS);
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);
auxSolidTorus (0.275, 0.85);
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);
auxSolidCube (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);
auxSolidSphere (1.0);
glPopMatrix ();

glPushMatrix ();
glTranslatef (0.70, -0.90, 0.25);
glMaterialfv(GL_FRONT, GL_DIFFUSE, octa_diffuse);
auxSolidOctahedron (1.0);
glPopMatrix ();

glPopMatrix ();
}

#define ACSIZE 8

void CALLBACK display(void)
{
GLint viewport[4];
int jitter;

glGetIntegerv (GL_VIEWPORT, viewport);

if(!viewport[3]) return;

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

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

/* Main Loop
* Open window with initial window size, title bar,
* RGBA display mode, and handle input events.
*/
int main(int argc, char** argv)
{
auxInitDisplayMode (AUX_DOUBLE | AUX_RGB
| AUX_ACCUM | AUX_DEPTH16);
auxInitPosition (0, 0, 250, 250);
auxInitWindow ("Scene Antialiasing");
myinit();
auxReshapeFunc (myReshape);
auxMainLoop(display);
return(0);
}