오픈GL 질감및 간단한 빛 설정 ....

// This program shows a simple tracball control
#include <math.h>
#include <iostream>
#include <GL/glut.h>
 
//for texture mapping 
//#include <GL/glext.h>
 
#ifndef M_PI
#define M_PI 3.14159
#endif
 
int winWidth, winHeight;
float trans[] = {0, 0, 0};
float rot_x = 0, rot_y = 0;
int last_x = 0, last_y = 0;
 
// draw a unit sphere
GLfloat s_red = 1.0, s_green = 1.0, s_blue = 1.0;  // 빛의 광원의 색 결정 
 
GLfloat d_red = 1.0, d_green = 1.0, d_blue = 1.0;  //물체의 색 결정
GLfloat a_red = 1.0, a_green = 1.0, a_blue = 1.0;   //
 
// MENU CONSTRUCTION
int menu; // for menu
 
int menu_parameter;
 
// sphere can be considered as a surface of revolution
void draw_sphere()
{
	const int ntheta = 40;
	const int nphi = 20;
 
	double delta_theta = 2.0 * M_PI / (ntheta-1);
	double delta_phi = M_PI / (nphi-1);
 
	double theta = 0, phi = 0;
 
	glBegin(GL_QUADS);
	for(int i=0; i<nphi-1; i++, phi += delta_phi)
	{
		for(int j=0; j<ntheta-1; j++, theta+=delta_theta)
		{
			float x1 = cos(theta)*sin(phi);
			float y1 = sin(theta)*sin(phi);
			float z1 = cos(phi);
 
			float x2 = cos(theta)*sin(phi+delta_phi);
			float y2 = sin(theta)*sin(phi+delta_phi);
			float z2 = cos(phi+delta_phi);
 
			float x3 = cos(theta+delta_theta)*sin(phi+delta_phi);
			float y3 = sin(theta+delta_theta)*sin(phi+delta_phi);
			float z3 = cos(phi+delta_phi);
 
			float x4 = cos(theta+delta_theta)*sin(phi);
			float y4 = sin(theta+delta_theta)*sin(phi);
			float z4 = cos(phi);
 
			float nx = (y3-y2)*(z1-z2) - (y1-y2)*(z3-z2);
			float ny = (x1-x2)*(z3-z2) - (x3-x2)*(z1-z2);
			float nz = (x3-x2)*(y1-y2) - (x1-x2)*(y3-y2);
 
			float mag = sqrtf(nx*nx+ny*ny+nz*nz);
			glNormal3f(nx/mag, ny/mag, nz/mag);
 
			glVertex3f(x1,y1,z1);
			glVertex3f(x2,y2,z2);
			glVertex3f(x3,y3,z3);
			glVertex3f(x4,y4,z4);
		}
	}
	glEnd();
}
 
 
void display(void)
{
	glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
 
	glPushMatrix(); // Holds current coordinates system
 
	glTranslatef(trans[0],trans[1],-4+trans[2]);
 
	glRotatef(rot_x, 1, 0, 0);
	glRotatef(rot_y, 0, 1, 0);
 
	draw_sphere();
 
	glPopMatrix();  // Set original coordinate system
 
	glutSwapBuffers();
}
 
 
void mouseButton(int button, int state, int x, int y)
{
	if(button==GLUT_LEFT_BUTTON && state==GLUT_DOWN) 
	{
		last_x = x;
		last_y = y;
	} 
}
 
void mouseMotion(int x, int y)
{
	int dx = x - last_x;
	int dy = y - last_y;
 
	last_x = x, last_y = y;
 
	rot_x += dy * 180.0f / winHeight;
	rot_y += dx * 180.0f / winWidth;
 
	if( rot_x > 360 ) rot_x -= 360;
	if( rot_y > 360 ) rot_y -= 360;
 
	glutPostRedisplay();
}
 
void keyboard(unsigned char key, int x, int y)
{
	switch (key) 
	{
	case '.': // for zoom control
		trans[2] += 0.1;
		break;
	case ',':
		trans[2] -= 0.1;
		break;
	case 27:
		exit(0);
		break;
	}
	glutPostRedisplay();
}
 
void special(int key, int x, int y)
{
	switch(key)
	{
	case GLUT_KEY_LEFT:
		trans[0] -= 0.1;
		break;
	case GLUT_KEY_RIGHT:
		trans[0] += 0.1;
		break;
	case GLUT_KEY_UP:
		trans[1] += 0.1;
		break;
	case GLUT_KEY_DOWN:
		trans[1] -= 0.1;
		break;
	}
	glutPostRedisplay();
}
 
 
void myReshape(int w, int h)
{
	glViewport(0, 0, w, h);
	winWidth = w;
	winHeight = h;
}
 
void menu_selected(int entry)
{
	switch(entry)
	{
	case 1: // Yellow Plastic Mode 
		printf("yellow plastic\n");
		glDisable(GL_LIGHTING);
		glEnable(GL_LIGHTING);
 
		d_red = 1.0;
		d_green = 1.0;
		d_blue = 1.0;  //물체의 색 결정
		draw_sphere();	//re-draw sphere
 
		//glDisable(GL_LIGHTING);
		//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
		break;
	case 2:
		glEnable(GL_LIGHTING);
		glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
		break;
 
 
	case 6:		// QUIT case 
		exit(0);
		break;
	}
	glutPostRedisplay();
}
 
void init(void) 
{
	//GLfloat red = 1.0, green = 1.0, blue = 1.0;
	//Define parameters for the material
	GLfloat mat_specular[]={s_red, s_green, s_blue, 1.0};		// 반사에 대한 반사값
	GLfloat mat_diffuse[]={d_red, d_green, d_blue, 1.0};	//	분산광에 대한 반사값
	GLfloat mat_ambient[]={a_red, a_green, a_blue, 1.0};	//주변광에 대한 반사값
	GLfloat mat_shininess={100.0};					// 광택 
 
	//Define parameters for the light
	GLfloat light_ambient[]={0.0, 0.0, 0.0, 1.0};  //주변광의 강도
	GLfloat light_diffuse[]={0.5, 0.5, 0.5, 1.0};	// 분산광의 강도
	GLfloat light_specular[]={1.0, 1.0, 1.0, 1.0};	// 반사광의 강도
 
	//Not used yet 
	//GLfloat lit_pos[4]={6.0, 6.0, -9.0, 1.0};// 광원의 위치
 
	//Set ambient, diffuse, and specular components for light 0 
	glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
	glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
	glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
 
	// Position of GL LIGHT 
	//glLightfv(GL_LIGHT0, GL_POSITION, lit_pos);
 
	//Set material proerties for front face of all polygons 
	glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
	glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);
	glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
	glMaterialf(GL_FRONT, GL_SHININESS, mat_shininess);
 
	//Enable the various shading features
	glEnable(GL_FLAT);      // enable smooth shading 
	glEnable(GL_LIGHTING);    // enable lighting 
	glEnable(GL_LIGHT0);      // enable light 0 
	glEnable(GL_DEPTH_TEST);  // enable z buffer 
	glEnable(GL_CULL_FACE);
 
	glMatrixMode(GL_PROJECTION);
	gluPerspective(50, 1, 0.1, 100);
 
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
 
	//build a submenu
	glutCreateMenu(menu_selected);
	glutAddMenuEntry("PARAMETER",0);
	glutAddMenuEntry("YELLOW PLASTIC",1);
	glutAddMenuEntry("BRASS METAL",2);
	glutAddMenuEntry("Texture Map",3);
	glutAddMenuEntry("Environment Map",4);
	glutAddMenuEntry("MOVE EYE/LIGHT",5);
	glutAddMenuEntry("QUIT",6);
	glutAttachMenu(GLUT_RIGHT_BUTTON);
 
	//Build a submenu : Parameter 
 
 
}
 
 
void main(int argc, char **argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
	glutInitWindowSize(500, 500);
	glutCreateWindow("simple tracball demo");
	glutReshapeFunc(myReshape);
	glutDisplayFunc(display);
 
	glutMouseFunc(mouseButton);
	glutMotionFunc(mouseMotion);
 
	glutKeyboardFunc(keyboard);
	glutSpecialFunc(special);
 
	init();
 
	glutMainLoop();
}