/*
 * (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);

    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 CALLBACK myReshape(GLsizei w, GLsizei h)
{
    h = (h == 0) ? 1 : 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_SINGLE | AUX_RGB
            | AUX_ACCUM | AUX_DEPTH16);
    auxInitPosition (0, 0, 250, 250);
    auxInitWindow ("Scene Antialiasing");
    myinit();
    auxReshapeFunc (myReshape);
    auxMainLoop(display);
    return(0);
}
