/*
 * (c) Copyright 1993, Silicon Graphics, Inc.
 *               1993, 1994 Microsoft Corporation
 *
 * ALL RIGHTS RESERVED
 *
 * Please refer to OpenGL/readme.txt for additional information
 *
 */

/*
 *  antiindex.c 
 *  The program draws a wireframe icosahedron with 
 *  antialiased lines, in color index mode.
 */
#include "glos.h"

#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glaux.h>

void myinit(void);
void CALLBACK myReshape(GLsizei w, GLsizei h);
void CALLBACK display(void);

#define RAMPSIZE 16
#define RAMPSTART 32

/*  Initialize antialiasing for color index mode, 
 *  including loading a grey color ramp starting 
 *  at RAMPSTART, which must be a multiple of 16.
 */
void myinit(void)
{
    int i;

    for (i = 0; i < RAMPSIZE; i++) {
    GLfloat shade;
    shade = (GLfloat) i/(GLfloat) RAMPSIZE;
    auxSetOneColor(RAMPSTART+(GLint)i, shade, shade, shade);
    }

    glEnable (GL_LINE_SMOOTH);
    glHint (GL_LINE_SMOOTH_HINT, GL_DONT_CARE);
    glLineWidth (1.5);

    glClearIndex ((GLfloat) RAMPSTART);
    glShadeModel(GL_FLAT);
    glDepthFunc(GL_LESS);
    glEnable(GL_DEPTH_TEST);
}

/*  display() draws an icosahedron.
 */
void CALLBACK display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glIndexi(RAMPSTART);
    auxWireIcosahedron(1.0);
    glFlush();
}

void CALLBACK myReshape(GLsizei w, GLsizei h)
{
    h = (h == 0) ? 1 : h;
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective (45.0, (GLfloat) w/(GLfloat) h, 3.0, 5.0);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity ();
    glTranslatef (0.0, 0.0, -4.0);  /*  move object into view   */
}

/*  Main Loop
 *  Open window with initial window size, title bar, 
 *  color index display mode, depth buffer, 
 *  and handle input events.
 */
int main(int argc, char** argv)
{
    auxInitDisplayMode (AUX_SINGLE | AUX_INDEX | AUX_DEPTH16);
    auxInitPosition (0, 0, 400, 400);
    auxInitWindow ("Antialiased Lines Using Color Index");
    myinit();
    auxReshapeFunc (myReshape);
    auxMainLoop(display);
    return(0);
}
