#include <iostream>
#include <GL/glew.h>
#include <GL/freeglut.h>
#include <GL/glext.h>

#include <cmath>
#include <sstream>

using namespace std;

void Projection();

// moving the objects about
GLfloat Sun_X_POS,
        Sun_Y_POS,
	Sun_Z_POS,
	Sun_Radius,
	Sun_Angle1,
	Sun_Angle2,
        Sun_Rotation,
	Planet_X_POS,
	Planet_Z_POS,
	Planet_Radius,
	Planet_Angle,
	Planet_Rotation;

// moving the camera about
GLfloat EyeX,
        EyeY,
	EyeZ;

// controling the projection
GLfloat FOV, ASPECT;

void DisplayString(void * font, string s) {
    int i;

    for(i=0; i < s.size(); i++) {
        glutStrokeCharacter(font, s[i]);
    }

    return;
}

void display() {

   stringstream s;

   s << "Current Position (" << EyeX << ", " << EyeY << ", " << EyeZ << ")";

   glClear(GL_COLOR_BUFFER_BIT);

   glLoadIdentity();
   glPushMatrix();
   glTranslatef(-1.3,1.3,-3);
   glScalef(0.001, 0.001, 0.001);
   DisplayString(GLUT_STROKE_ROMAN,s.str());
   glPopMatrix();

   gluLookAt(EyeX,EyeY,EyeZ,0,0,0,0,1,0);

   glColor3f(1,0,0);


   // put the sun up in the sky
   glPushMatrix();
   glTranslatef(Sun_X_POS,Sun_Y_POS,Sun_Z_POS);
   // spin the sun.
   glRotatef(Sun_Rotation, 0,1,0);
   // I don't like the original orientation of the sun, so spin it.
   glRotatef(60, 1,1,0);
   glutWireSphere(2,12,12);

   // put a planet near the sun
   glTranslatef(Planet_X_POS,0,Planet_Z_POS);
   glRotatef(Planet_Rotation, 0,1,0);
   glutWireSphere(.5,5,5);
   
   glPopMatrix();

   glColor3f(0.2, 0.8, 0.5);
   glutWireTeapot(.25);

   glColor3f(0.7, 0.2, 0.9);
   glutWireCube(10);

   glColor3f(0.7, 0.2, 0.9);
   glScalef(.001, .001, .001);
   glPushMatrix();
   DisplayString(GLUT_STROKE_ROMAN,"This is the X axis");
   glPopMatrix();
   glPushMatrix();
   glRotatef(90,0,0,1);
   DisplayString(GLUT_STROKE_ROMAN,"This is the Y axis");
   glPopMatrix();

   glFlush();
   return;
}

void reset() {

   Sun_Rotation = 0;
   Sun_Angle1 = 90;
   Sun_Angle2 = 90;
   Sun_Radius = 8;
   Sun_X_POS = Sun_Radius*cos(Sun_Angle1)*sin(Sun_Angle2);
   Sun_Y_POS = Sun_Radius*sin(Sun_Angle1)*sin(Sun_Angle2);
   Sun_Z_POS = Sun_Radius*cos(Sun_Angle2);

   Planet_Angle = 0;
   Planet_Radius = 3;
   Planet_X_POS = Planet_Radius * cos(Planet_Angle);
   Planet_Z_POS = Planet_Radius * sin(Planet_Angle);
   Planet_Rotation = 0;
   EyeX = 0;
   EyeY = 0;
   EyeZ = 10;

   FOV = 60;
   ASPECT = 1;
   Projection();
   return;
}

void idle() {
   Sun_X_POS = Sun_Radius*cos(Sun_Angle1)*sin(Sun_Angle2);
   Sun_Y_POS = Sun_Radius*sin(Sun_Angle1)*sin(Sun_Angle2);
   Sun_Z_POS = Sun_Radius*cos(Sun_Angle2);

   Sun_Angle1 += .001;
   Sun_Angle2 += .002;

   Sun_Rotation += 0.1;
   if (Sun_Rotation > 360) {
       Sun_Rotation -= 360;
   }
  
   Planet_Angle += 0.01;
   Planet_X_POS = Planet_Radius*cos(Planet_Angle);
   Planet_Z_POS = Planet_Radius*sin(Planet_Angle);
   Planet_Rotation += 0.5;
   if (Planet_Rotation > 360) {
       Planet_Rotation -= 360;
   }

   glutPostRedisplay();

   return;
}

void setup() {
   reset();
   glClearColor(1,1,1,1);

   return;
}

void Projection() {

   cout << "Aspect " << ASPECT << endl;
   cout << "FOV " << FOV << endl;
   cout << endl;

   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   gluPerspective(FOV,ASPECT,1, 30);
   //glFrustum(-1.0, 1.0, -1.0, 1.0, 1, 20);
   glMatrixMode(GL_MODELVIEW);

   return;
}


void resize(int w, int h) {
   glViewport(0, 0, w, h);
   Projection();
   glLoadIdentity();

   return;
}



void  keypress (unsigned char key, int x, int y) {

   GLfloat increment = 0.25;

   switch(key) {
     case 'a':
         ASPECT -= 0.1;
         Projection();
	 break;
     case 'A':
         ASPECT += 0.1;
         Projection();
	 break;
     case 'f':
         FOV -= 2;
         Projection();
	 break;
     case 'F':
         FOV += 2;
         Projection();
	 break;
     case 'i':
         EyeY += increment; 
	 break;
     case 'n':
         EyeY -= increment; 
	 break;
     case 'h':
         EyeX -= increment; 
	 break;
     case 'j':
         EyeZ -= increment; 
	 break;
     case 'k':
         EyeZ += increment; 
	 break;
     case 'l':
         EyeX += increment; 
	 break;
     case 'r': 
         reset();
	 break;
     case 'q':
          exit(0);
   }
   glutPostRedisplay();
   return;
}

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

   glutInitContextVersion(3, 0);
   glutInitContextProfile(GLUT_COMPATIBILITY_PROFILE);

   glutInitDisplayMode(GLUT_SINGLE | GLUT_RGBA);
   glutInitWindowSize(500, 500);
   glutCreateWindow("A Demo");
   glutDisplayFunc(display);
   glutReshapeFunc(resize);
   glutKeyboardFunc(keypress);

   glutIdleFunc(idle);
   glewExperimental = GL_TRUE;
   glewInit();

   setup();

   glutMainLoop();
}