#include <GL/gl.h>
#include <GL/glu.h>
#include "aux.h"

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


	GLfloat light1_ambient[] = { 0.2, 0.2, 0.2, 1.0 };
	GLfloat light1_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
	GLfloat light1_specular[] = { 1.0, 1.0, 1.0, 1.0 };
	GLfloat light1_position[] = { -2.0, 2.0, 1.0, 1.0 };
	GLfloat spot_direction[] = { 1.0, -1.0, 0.0 }; 


	glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
	glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);
	glLightfv(GL_LIGHT0, GL_POSITION, light_position);
	glLightfv(GL_LIGHT1, GL_AMBIENT, light1_ambient);
	glLightfv(GL_LIGHT1, GL_DIFFUSE, light1_diffuse);
	glLightfv(GL_LIGHT1, GL_SPECULAR, light1_specular);
	glLightfv(GL_LIGHT1, GL_POSITION, light1_position);
	glLightf(GL_LIGHT1, GL_CONSTANT_ATTENUATION, 1.5);
	glLightf(GL_LIGHT1, GL_LINEAR_ATTENUATION, 0.0);
	glLightf(GL_LIGHT1, GL_QUADRATIC_ATTENUATION, 0.0); 

	glLightf(GL_LIGHT1, GL_SPOT_CUTOFF, 45.0);
	glLightfv(GL_LIGHT1, GL_SPOT_DIRECTION, spot_direction);
	glLightf(GL_LIGHT1, GL_SPOT_EXPONENT, 2.0); 


	glEnable(GL_LIGHTING);
	glEnable(GL_LIGHT0); 
	glEnable(GL_LIGHT1);
	glDepthFunc(GL_LESS);
	glEnable(GL_DEPTH_TEST);
}

void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    auxSolidSphere(1.0);
    glFlush();
}

void myReshape(int w, int h)
{
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    if (w <= h) 
	glOrtho (-1.5, 1.5, -1.5*(GLfloat)h/(GLfloat)w, 
	    1.5*(GLfloat)h/(GLfloat)w, -10.0, 10.0);
    else 
	glOrtho (-1.5*(GLfloat)w/(GLfloat)h, 
	    1.5*(GLfloat)w/(GLfloat)h, -1.5, 1.5, -10.0, 10.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

int main(int argc, char** argv)
{
    auxInitDisplayMode (AUX_SINGLE | AUX_RGB | AUX_DEPTH);
    auxInitPosition (0, 0, 500, 500);
    auxInitWindow (argv[0]);
     myinit();
    auxReshapeFunc (myReshape);
    auxMainLoop(display);
}