/* Basic i/o libraries */
#include <stdio.h>
#include <stdlib.h>

/* OpenGL defines/includes */
#define GLUT_DISABLE_ATEXIT_HACK
#include <stdarg.h>
#include <GL\gl.h>
#include <GL\glu.h>
#include <GL\glut.h>

void MakeWindow(void);

void WindowDisplay(void);

void WindowKeyboard(unsigned char key, int x, int y);

void WindowReshape(int w, int h);

void DrawTrajectory(int x, int y, int v, float t);

int xcalc(float v, float t, float ti);

int ycalc(float v, float t, float ti);

void DrawTank(int x,int y);

float DR(float x);

int wnd;

int main(int argc, char *argv[])
{
  glutInit(&argc, argv); /* Initialize glut */
  
  MakeWindow();
  
  glutMainLoop();
  return 0;
}

void MakeWindow(void)
{
  glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
  glutInitWindowSize(500,500);

  wnd = glutCreateWindow("Draw");
  glClearColor(1,1,1,0);		/* set clear color to white */

  glutDisplayFunc(WindowDisplay);
  glutKeyboardFunc(WindowKeyboard);
  glutReshapeFunc(WindowReshape);
}

void WindowDisplay(void)
{
  DrawTrajectory(5,5,60,45);
  glutSwapBuffers();
}

void WindowKeyboard(unsigned char key, int x, int y)
{
  if( key == 'q' || key == 'Q' ) exit(0);
}

void WindowReshape(int w, int h)
{
  glViewport(0, 0, w, h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluOrtho2D(0, w, h, 0);
  glMatrixMode(GL_MODELVIEW);
}

int xcalc(float v, float t, float ti)
{
    return (int) (v*ti)*cos(t);
}

int ycalc(float v, float t, float ti)
{
    return (int) (v*ti)*sin(t)-4.905*(ti*ti);
}

void DrawTrajectory(int x, int y, int v, float t){
  float time=.01; int tx=0,ty=0;
  printf("Drawing Trajectory: From Point (%d,%d); Velocity %d; Angle %d\n", x,y,v,t);
  t = DR(t);
  printf("Angle: %d", t);
  glClear(GL_COLOR_BUFFER_BIT);
  glColor3f(0,0,0);
  glBegin(GL_POINTS);
  while (ty>=0) {
        tx=xcalc((float)v,(float)t,time);
        ty=ycalc((float)v,(float)t,time);
        printf("Point drawn at (%d,%d)\n",tx,ty);
        glVertex2i(tx,ty);
        time=time+.01;
  }
  
  glEnd();
}

void DrawTank(int x,int y){

  glColor3f(1,0,0);
  glBegin(GL_POLYGON);
  glVertex2i(x,y);
  glVertex2i(x,25+y);
  glVertex2i(50+x,25+y);
  glVertex2i(50+x,y);
  glEnd();
}

float DR(float x){
     return x * (3.14/180);
}