/*  planet.c
 *
 *  Derived from:  planet.c   in
 *  Jeff Molofee's OpenGL Windows Tutorials
 *  http://nehe.gamedev.net/
 *
 *  Bruce M. Bolden
 *  October 23, 2001
 */

#include <stdio.h>
/*  for Windows 95/98/NT
#include <windows.h>
#include <gl/Gl.h>
#include <gl/Glu.h>
#include <gl/glut.h>
*/
#include <GLUT/glut.h>   /*  OS X */

    //  Prototypes
void init( void );
void display( void );
void keyboard( unsigned char key, int x, int y );
void reshape( int w, int h );


static int year = 0, day = 0;


void init(void)
{
    glClearColor( 0.0, 0.0, 0.0, 0.0 );
    glShadeModel( GL_FLAT );
}

void display( void )
{
    glClear( GL_COLOR_BUFFER_BIT );  //BB:  added | GL_DEPTH_BUFFER_BIT
    glColor3f( 1.0, 1.0, 1.0 );
    glPushMatrix();
    glutWireSphere( 1.0, 20, 16 ); /* draw sun */
    glRotatef( (GLfloat)year, 0.0, 1.0, 0.0 );
    glTranslatef( 2.0, 0.0, 0.0 );
    glRotatef( (GLfloat)day, 0.0, 1.0, 0.0 );
    glutWireSphere( 0.2, 10, 8 ); /* draw smaller planet */
    glPopMatrix();
    glutSwapBuffers();

    glutPostRedisplay ();   //BB:  added
}


void reshape( int w, int h )
{
    glViewport( 0, 0, (GLsizei)w, (GLsizei)h );
    glMatrixMode( GL_PROJECTION );
    glLoadIdentity();
    gluPerspective( 60.0, (GLfloat)w/(GLfloat)h, 1.0, 20.0 );

    glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();
    gluLookAt( 0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0 );

    glutPostRedisplay();   //BB:  added
}


void keyboard( unsigned char key, int x, int y )
{
    switch ( key )
    {
    case 'd':
        day = (day + 10) % 360;
        break;
    case 'D':
        day = (day - 10) % 360;
        break;
    case 'y':
        year = (year + 5) % 360;
        break;
    case 'Y':
        year = (year - 5) % 360;
        break;
    default:
        break;
    }
    glutPostRedisplay();
}


int main(int argc, char** argv)
{
    glutInit( &argc, argv );
    glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB );  //  added | GLUT_DEPTH
    glutInitWindowSize( 500, 500 );
    glutInitWindowPosition( 100, 100 );
    glutCreateWindow( "Planet" );   //BB:  "Planet" was argv[0]

    init();

    glutDisplayFunc( display );
    glutReshapeFunc( reshape );
    glutKeyboardFunc( keyboard );

    glutMainLoop();

    return 0;
}