#include "glut.h"void changeSize( int w, int h ){	// Prevent a divide by zero, when window is too short	// (you cant make a window of zero width).	if(h == 0)		h = 1;	float ratio = 1.0f * w / h;	// Reset the coordinate system before modifying	glMatrixMode(GL_PROJECTION);	glLoadIdentity();	// Set the viewport to be the entire window	glViewport(0, 0, w, h);	// Set the clipping volume	gluPerspective( 45, ratio, 1, 1000 );	glMatrixMode( GL_MODELVIEW );	glLoadIdentity();}void initScene() {	glEnable(GL_DEPTH_TEST);}void renderScene(void) {	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	glutSwapBuffers();}void processNormalKeys(unsigned char key, int x, int y) {	if (key == 27) 		exit(0);}void inputKey(int key, int x, int y) {	switch (key) 	{		case GLUT_KEY_LEFT : 			break;		case GLUT_KEY_RIGHT : 			break;		case GLUT_KEY_UP : 			break;		case GLUT_KEY_DOWN : 			break;	}}void processMouse(int button, int state, int x, int y) {	int specialKey = glutGetModifiers();	// if both a mouse button, and the ALT key, are pressed  then	if ((state == GLUT_DOWN) && (specialKey == GLUT_ACTIVE_ALT)) 	{		// set the color to pure red for the left button		// if (button == GLUT_LEFT_BUTTON) 		// set the color to pure green for the middle button		//else if (button == GLUT_MIDDLE_BUTTON) 				// set the color to pure blue for the right button		// else	}}void processMouseActiveMotion(int x, int y) {	//if (specialKey == GLUT_ACTIVE_SHIFT) 	//else if (specialKey == GLUT_ACTIVE_CTRL)	//else if (specialKey == GLUT_ACTIVE_ALT)	//else}void processMousePassiveMotion(int x, int y) {	//if (specialKey == GLUT_ACTIVE_SHIFT) 	//else if (specialKey == GLUT_ACTIVE_CTRL)	//else if (specialKey == GLUT_ACTIVE_ALT)	//else}void processMouseEntry(int state) {	//if ( state == GLUT_LEFT )	//if( state == GLUT_ENTERED )}int main(int argc, char **argv){	glutInit(&argc, argv);	glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);	glutInitWindowPosition(100,100);	glutInitWindowSize(640,360);	glutCreateWindow("GLUT");	initScene();		// Keyboard	glutKeyboardFunc(processNormalKeys);	glutSpecialFunc(inputKey);	// Display and Idle	glutDisplayFunc(renderScene);	glutIdleFunc(renderScene);	glutReshapeFunc(changeSize);	// Mouse stuff	glutMouseFunc(processMouse);	glutMotionFunc(processMouseActiveMotion);	glutPassiveMotionFunc(processMousePassiveMotion);	glutEntryFunc(processMouseEntry);	glutMainLoop();	return(0);}