/* File: step2.c
   Author: Katia Oleinik

   This example demonstrates 

   - optional call-back routines
   - adjusting the viewport based on window size 

    Solution to the assignment: 
   1. Enable a Keyboard callback routine that prints the pressed key in the command window
   2. Make program exit when "q" or "Q" is pressed
   3. Enable a Mouse callback routine that prints on the screen the information about which mouse button was pressed

*/

#include <stdio.h>
#include <stdlib.h>
#include <GL/glut.h>

/* user defined functions declarations */
void keypress( unsigned char key, int x, int y);
void specialkeys(int key, int x, int y);
void mousepress( int button, int state, int x, int y);
void resize(int width, int height);
void mydraw(void);
void display(void);
void init(void);


/* keyboard callback routine */
void keypress( unsigned char key, int x, int y) 
{
  // output the key
  printf(" The ASCII code for \'%c\' is %i\n",key, key);

  if (key == 'q' || key =='Q' || key ==27)exit(0);   // exit
}

/* handle special keys */
void specialkeys(int key, int x, int y)
{
	switch (key)
	{
	case GLUT_KEY_LEFT:
		printf(" Left\n");
		break;
	case GLUT_KEY_RIGHT:
		printf(" Right\n");
		break;
	}
}

/* mouse click callback routine */
void mousepress( int button, int state, int x, int y)
{
  if (state != GLUT_DOWN)return;
  switch (button)
    {
    case GLUT_LEFT_BUTTON:
      printf("Left mouse button pressed\n");
      break;
    case GLUT_MIDDLE_BUTTON:
      printf("Middle mouse button pressed\n");
      break;
    case GLUT_RIGHT_BUTTON:
      printf("Right mouse button pressed\n");
      break;
    }

  printf( " Mouse coordinates: %d %d\n",x,y);
}


/* callback routine to respond on resize of the window */
void resize(int width, int height)
{
  double aspect;

  /* Reset the viewport */
  glViewport(0,0,width,height);
  
  /* compute aspect */
  aspect = (double)width / (double)height;

  /* Set up the perspective matrix accordingly */
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity(); //reset projection matrix

  /* make sure that the clipping planes are set to the original values 
     in the smallest direction */
  if (aspect < 1.0) glOrtho(-4., 4., -4./aspect, 4./aspect, 1., 10.);
  else glOrtho(-4.*aspect, 4.*aspect, -4., 4., 1., 10.);

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();

  /* Set Camera Position */
  gluLookAt(0., 0., 5., 0., 0., 0., 0., 1., 0.);
  
}

/* drawing routine, called by display every animated frame */
void mydraw(void)
{
  glColor3f( 1.0, 0.5, 0.0);    // orange color
  glutSolidSphere(1., 24, 24);  //draw sphere
}

/* display is called by the glut main loop once for every animated frame */
void display(void)
{
  /* initialize color and depth buffers */
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  /* call the routine that actually draws what you want */
  mydraw();

  /* show the just-filled frame buffer */
  glutSwapBuffers();
}

/* called once to set up basic opengl state */
void init(void)
{
  /* Use depth buffering for hidden surface elimination. */
  glEnable(GL_DEPTH_TEST);

  /* Set up the perspective matrix */
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();

  /* Define perspective matrix */
  glOrtho(-4., 4., -4., 4., 1, 10.);

  /* Set up the model view matrix */
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();

  /* Define Camera Position */
  gluLookAt(0., 0., 5., 0., 0., 0., 0., 1., 0.);
}

int main(int argc, char **argv)
{

  /* GLUT Configuration */
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
  glutInitWindowSize(500,500); 
  glutInitWindowPosition(100,100);

  /* Create Window */
  glutCreateWindow("Orange Ball");

  /* Set display as a callback for the current window */
  glutDisplayFunc(display);

  /* Set callback function that respond to resizing the window */
  glutReshapeFunc(resize);

  /* Set callback function that responds on keyboard pressing */
  glutKeyboardFunc (keypress);

  /* Set callback function to respond to special keys pressing */
  glutSpecialFunc(specialkeys);

  /* Set callback function that responds on the mouse click */
  glutMouseFunc(mousepress); 

  /* Set basic openGL states */
  init();

  /* Enter GLUT event processing loop */
  glutMainLoop();

  /* Exit the program */
  return 0;
}