#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>
#include <string.h>
//g++ main.cpp -lGL -lglut -lGLU
using namespace std;

float droll=0; //Yes, badly named, I know.
float dpitch=0;
int KeyDown[256];

void init(void) {
  glClearColor (0.0, 0.0, 0.0, 0.0);
  glShadeModel (GL_FLAT);
}

void display(void) {
/* Check this stuff out, yo.
http://gamedev.stackexchange.com/questions/12885/help-understanding-glulookat
WhatisthisIdon'teven.*/
  glClear (GL_COLOR_BUFFER_BIT);
  glColor3f (1.0, 1.0, 1.0);
  glLoadIdentity ();             /* clear the matrix */
          /* viewing transformation  */
  gluLookAt (0.0, 0.0, 6.0, 0.0, 0.0+dpitch, 0.0+droll, 0.0, 1.0, 0.0);
  glScalef (1.0, 1.0, 1.0);      /* modeling transformation */
  glutWireCube (1.0);
  glFlush ();
}
void reshape (int w, int h) {
  glViewport (0, 0, (GLsizei) w, (GLsizei) h);
  glMatrixMode (GL_PROJECTION);
  glLoadIdentity ();
  glFrustum (-1.0, 1.0, -1.0, 1.0, 1.5, 200.0);
  glMatrixMode (GL_MODELVIEW);
}

void mousefunc(int button,int state,int x,int y) {
  switch(button) {
    case GLUT_LEFT_BUTTON:
      glutPostRedisplay();
      break;
    case GLUT_RIGHT_BUTTON:
      glutPostRedisplay();
      break;
  }
}
void keyboardfunc(unsigned char key,int x,int y) {
  KeyDown[key]=1;
}
void keyboardUpfunc(unsigned char key,int x,int y) {
  KeyDown[key]=0;
}
void idlefunc() {
  if(KeyDown['a']) {
    droll-=0.01;
  }
  else if(KeyDown['d']) {
    droll+=0.01;
  }
  else if(KeyDown['s']) {
    dpitch-=0.01;
  }
  else if(KeyDown['w']) {
    dpitch+=0.01;
  }
  glutPostRedisplay();
}

int main(int argc, char** argv) {
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
  glutInitWindowSize(500, 500);
  glutInitWindowPosition(100, 100);
  glutCreateWindow(argv[0]);
  init();

  glutDisplayFunc(display);
  glutReshapeFunc(reshape);

  memset(KeyDown,0,sizeof(KeyDown));
  glutMouseFunc(mousefunc);
  glutKeyboardFunc(keyboardfunc);
  glutKeyboardUpFunc(keyboardUpfunc);
  glutIdleFunc(idlefunc);
  glutMainLoop();
  return 0;
}