#include "..\glut.h"
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <iostream.h>

/* global variable declarations */

int plusOrMinus = 1;
int xYorZ = 4;
GLfloat myX = 30.0, myY = 20.0, myZ = 100.0;
float matSpecular[] = {1.0, 1.0, 1.0, 1.0};
float matAmbient[] = {1.0, 1.0, 1.0, 1.0};
float matDiffuse[] = {1.0, 1.0, 1.0, 1.0};
float matShininess = 50.0;
/* function declarations ----------------------------------*/

void myInit(){

    glClearColor(0.0, 0.0, 0.0, 1.0);
    glColor3f(1.0, 1.0, 1.0);

	glEnable(GL_DEPTH_TEST);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-100.0, 100.0, -100.0, 100.0, -100.0, 100.0);

} // end of myInit()

/* --------------------------------------------------------*/

void myDisplay()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
    gluLookAt(myX, myY, myZ, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

    // positive axes in blue
	glColor3f(0.0, 0.6, 0.8);
	glBegin(GL_LINES);
	    glVertex3f(100.0, 0.0, 0.0);
		glVertex3f(0.0, 0.0, 0.0);
		glVertex3f(0.0, 100.0, 0.0);
		glVertex3f(0.0, 0.0, 0.0);
		glVertex3f(0.0, 0.0, 100.0);
	    glVertex3f(0.0, 0.0, 0.0);
	glEnd();
    
    // negative axes in orange
	glColor3f(1.0, 0.4, 0.2);
	glBegin(GL_LINES);
	    glVertex3f(-100.0, 0.0, 0.0);
		glVertex3f(0.0, 0.0, 0.0);
		glVertex3f(0.0, -100.0, 0.0);
		glVertex3f(0.0, 0.0, 0.0);
		glVertex3f(0.0, 0.0, -100.0);
	    glVertex3f(0.0, 0.0, 0.0);
	glEnd();
    
    // 5 lightgreen tetrahedra
    for (int t = -2; t <= 2; t++) {

    glColor3f(0.6, 1.0, 0.8);
	glBegin(GL_POLYGON);
        glVertex3f(40.0*t, 30.0, 0.0);
		glVertex3f(40.0*t-10, 0.0, 0.0);
		glVertex3f(40.0*t+10, 0.0, 0.0);
	glEnd();
    glColor3f(0.0, 0.8, 0.6);
	glBegin(GL_POLYGON);
        glVertex3f(40.0*t, 30.0, 0.0);
		glVertex3f(40.0*t-10, 0.0, 0.0);
		glVertex3f(40.0*t, 0.0, 20.0);
	glEnd();
    glColor3f(0.2, 1.0, 0.8);
	glBegin(GL_POLYGON);
        glVertex3f(40.0*t, 30.0, 0.0);
		glVertex3f(40.0*t+10, 0.0, 0.0);
		glVertex3f(40.0*t, 0.0, 20.0);
	glEnd();
    glColor3f(0.2, 0.8, 0.4);
	glBegin(GL_POLYGON);
        glVertex3f(40.0*t, 0.0, 20.0);
		glVertex3f(40.0*t-10, 0.0, 0.0);
		glVertex3f(40.0*t+10, 0.0, 0.0);
	glEnd();

	} // end of for loop

	glutSwapBuffers();
} // end of myDisplay()

/* --------------------------------------------------------*/

void spinDisplay() {

	if (xYorZ == 1)
		myX += plusOrMinus*0.05;
	if (xYorZ == 2)
		myY += plusOrMinus*0.05;
	if (xYorZ == 3)
		myZ += plusOrMinus*0.05;

	// orbit around y axis from current position
	if (xYorZ == 4) {

		float oldX = myX;
        myX = cos(.314159/180)*myX - sin(.314159/180)*myZ;
		myZ = sin(.314159/180)*oldX + cos(.314159/180)*myZ;

	} // end of orbit code

	glutPostRedisplay();
}

/* --------------------------------------------------------*/

void myKeyboard(unsigned char key, int x, int y) {
    if (key == 'X' || key == 'x')
		xYorZ = 1;
    if (key == 'Y' || key == 'y')
		xYorZ = 2;
    if (key == 'Z' || key == 'z')
		xYorZ = 3;
    if (key == 'O' || key == 'o')
		xYorZ = 4;

	if (key == 'Q' || key == 'q')
		exit(0);
}

/* --------------------------------------------------------*/

void myMouse(int button, int state, int x, int y) {
	if (state == GLUT_DOWN) plusOrMinus *= -1;
}	

/* --------------------------------------------------------*/

void quit_menu(int id) {
	float lightPosition[] = {-30.0, 30.0, 30.0, 0.0};
	float lightDiffuseColor[] = {1.0, 0.0, 0.0, 1.0};
	float lightSpecularColor[] = {1.0, 1.0, 0.0, 1.0};
	float lightAmbientColor[] = {0.2, 0.2, 0.2, 1.0};

	switch (id) {
	    case 1:	xYorZ = 1; break;
        case 2:	xYorZ = 2; break;
        case 3:	xYorZ = 3; break;
		case 4: xYorZ = 4; break;
		case 5: xYorZ = 0; break;
		case 6: glEnable(GL_LIGHTING);
			    glEnable(GL_LIGHT0);
				glMatrixMode(GL_MODELVIEW);
				glLoadIdentity();
				glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
				glLightfv(GL_LIGHT0, GL_DIFFUSE, lightDiffuseColor);
				glLightfv(GL_LIGHT0, GL_SPECULAR, lightSpecularColor);
				glLightfv(GL_LIGHT0, GL_AMBIENT, lightAmbientColor);
				break;
        case 7: glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, matSpecular);
		        glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, matAmbient);
		        glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, matDiffuse);
		        glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, matShininess);
			    break;
		case 8: glDisable(GL_LIGHTING);
			    glDisable(GL_LIGHT0);
				break;
        default: exit(0);
	}	
	
}

/* --------------------------------------------------------*/
void myReshape(int w, int h) {
	
	glViewport(0, 0, w, h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(60.0, (double)w/h, 10.0, 200.0);
}

/* --------------------------------------------------------*/

int main(int argc, char **argv)
{
	glutInit(&argc, argv);

    /* set up display window */

    glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(400, 400);
    glutInitWindowPosition(150, 100);
    glutCreateWindow("Always Looking at the Origin");

    /* register callback functions */
    glutReshapeFunc( myReshape );
    glutDisplayFunc( myDisplay );
	glutKeyboardFunc( myKeyboard );
	glutIdleFunc( spinDisplay );
	glutMouseFunc( myMouse );

	/* add a menu! */
	glutCreateMenu(quit_menu);
    glutAddMenuEntry("move along x axis", 1);
    glutAddMenuEntry("move along y axis", 2);
    glutAddMenuEntry("move along z axis", 3);
	glutAddMenuEntry("orbit arount y axis", 4);
	glutAddMenuEntry("pause movement", 5);
	glutAddMenuEntry("turn lights on", 6);
	glutAddMenuEntry("turn on material properties", 7);
	glutAddMenuEntry("turn lights off", 8);
	glutAddMenuEntry("quit", 9);
	glutAttachMenu(GLUT_RIGHT_BUTTON);

    /* start the event loop */
    myInit();
    glutMainLoop();

    return 0;
} // end of main