/*
 *  light.java
 *  This program demonstrates the use of the OpenGL lighting
 *  model.  A sphere is drawn using a grey material characteristic.
 *  A single light source illuminates the object.
 */

import jgl.GL;
import jgl.GLApplet;

public class light extends GLApplet {

    /*
     *  Initialize material property, light source, lighting model,
     *  and depth buffer.
     */
    private void myinit () {
	float mat_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
	float mat_shininess[] = { 50.0f };
	float light_position[] = { 1.0f, 1.0f, 1.0f, 0.0f };

	myGL.glClearColor (0.0f, 0.0f, 0.0f, 0.0f);
	myGL.glShadeModel (GL.GL_SMOOTH);

	myGL.glMaterialfv (GL.GL_FRONT, GL.GL_SPECULAR, mat_specular);
	myGL.glMaterialfv (GL.GL_FRONT, GL.GL_SHININESS, mat_shininess);
	myGL.glLightfv (GL.GL_LIGHT0, GL.GL_POSITION, light_position);

	myGL.glEnable (GL.GL_LIGHTING);
	myGL.glEnable (GL.GL_LIGHT0);
	myGL.glEnable (GL.GL_DEPTH_TEST);
    }

    public void display () {
	myGL.glClear (GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
	myUT.glutSolidSphere (1.0, 20, 16);
	myGL.glFlush ();
    }

    public void myReshape (int w, int h) {
        myGL.glViewport (0, 0, w, h);
        myGL.glMatrixMode (GL.GL_PROJECTION);
        myGL.glLoadIdentity ();
        if (w <= h) {
            myGL.glOrtho (-1.5f,   1.5f, 
	    		  -1.5f*(float)h/(float)w, 
			   1.5f*(float)h/(float)w,
			  -10.0f, 10.0f);
        } else {
            myGL.glOrtho ( -1.5f*(float)w/(float)h,
	    		    1.5f*(float)w/(float)h,
			   -1.5f,  1.5f,
			  -10.0f, 10.0f);
        }
        myGL.glMatrixMode (GL.GL_MODELVIEW);
	myGL.glLoadIdentity ();
    }

    public void init () {
	myUT.glutInitWindowSize (500, 500);
	myUT.glutInitWindowPosition (0, 0);
	myUT.glutCreateWindow (this);
	myinit ();
	myUT.glutDisplayFunc ("display");
	myUT.glutReshapeFunc ("myReshape");
	myUT.glutMainLoop ();
    }

}