// BOX Movement using up-down-left-right key of the keyboard.
#include <gl/glut.h>
#include <stdio.h>
#include <math.h>

// Initial size of graphics window.
int WIDTH  = 800;
int HEIGHT = 600;

// Current size of window.
int width  = WIDTH;
int height = HEIGHT;

int noOfDisplayCalls=0;
float offset = 0;
int dir = 0;
int noOfTimer=0;

/**
  * TIMERSEC int
  * the amount of time (in milisecond) after which animate function is called
  */
const int TIMERMSECS = 5000;

const int BOX_WIDTH = 100;
const int BOX_HEIGHT = 30;

int boxleft = 350, boxtop=200;



void display ()
{
    // printf("calling display(%d)\n",++noOfDisplayCalls);
	// Function that clears the window. If you don't want to clear the view window, don't call glClear function. make it as a comment statement.
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	// --------------
	// YOUR CODE ...
	// --------------

	glColor3f(.5, .7, .1);
	glLineWidth(1);
	glBegin(GL_TRIANGLES);
          //if (dir==1)
	      glVertex2f(width/(double)WIDTH*100+offset,height/(double)HEIGHT*310);
	      //else
	      //glVertex2f(width/(double)WIDTH*30+offset,height/(double)HEIGHT*50+offset);

          glVertex2f(width/(double)WIDTH*100+offset,height/(double)HEIGHT*290);
          glVertex2f(width/(double)WIDTH*350,height/(double)HEIGHT*300);
          //glVertex2f(400+offset,600);//

    glBegin(GL_TRIANGLES);
          //if (dir==1)
	      glVertex2f(width/(double)WIDTH*360,height/(double)HEIGHT*100+offset);
	      //else
	      //glVertex2f(width/(double)WIDTH*30+offset,height/(double)HEIGHT*50+offset);

          glVertex2f(width/(double)WIDTH*340,height/(double)HEIGHT*100+offset);
          glVertex2f(width/(double)WIDTH*350,height/(double)HEIGHT*300);

	glEnd();

	glutSwapBuffers();
}


void mouseMovement(int mx, int my)
{
	// --------------
	// YOUR CODE ...
	// --------------
	//printf("(%d,%d)\n",mx,my);

	glutPostRedisplay();
}


void mouseAction(int button, int state, int x, int z)
  // Record cursor position in response to mouse button action
{
  switch(button){
  case GLUT_LEFT_BUTTON:
    if (state == GLUT_DOWN) {
              printf("Clicked\n");
    }
    else if(state==GLUT_UP){
         printf("Released\n");
    }
    break;
  }
} // end mouse

// Respond to window resizing, preserving proportions.
// Parameters give new window size in pixels.
void reshapeMainWindow (int newWidth, int newHeight)
{
     printf("Calling Reshape()\n");
	// ----------------------------
	// DO NOT ALTER THIS FUNCTION ...
	// ----------------------------

	glMatrixMode( GL_PROJECTION );
	glLoadIdentity();
	glOrtho( 0, newWidth, 0, newHeight, 0, 1 );
	glViewport( 0, 0, newWidth, newHeight );
	width = newWidth;
	height = newHeight;
    glMatrixMode(GL_MODELVIEW);
    //glutDisplayFunc(display);//
	glutPostRedisplay();
}


// Respond to graphic character keys.
// Parameters give key code and mouse coordinates.
void graphicKeys (unsigned char key, int x, int y)
{
     printf("Calling graphicKeys()\n");
	switch (key) {
           case 'p':{
                     offset++;
                     break;

                }
		case 'h':
			// --------------
			// YOUR CODE ...
			// --------------
			break;
		case 27: // Escape
			exit(0);
		default:
			printf("%c\n",key);
	}
	glutPostRedisplay();
}

// Respond to function keys.
// Parameters give key code and mouse coordinates.
void functionKeys (int key, int x, int y)
{
	switch (key)
	{

		case GLUT_KEY_UP:
			boxtop +=10;
			break;
		case GLUT_KEY_DOWN:
			boxtop -=10;
			break;
		case GLUT_KEY_LEFT:
			boxleft -= 10;
			break;
		case GLUT_KEY_RIGHT:
			boxleft += 10;
			break;
	}
	glutPostRedisplay();
}


void timer(int value) {
    printf("calling timer(%d)\n",++noOfTimer);
	// --------------
	// YOUR CODE ...
	// --------------

    glutTimerFunc(500, timer, 0);
	glutPostRedisplay();
}


void doThisAlways()
{
     //printf("Calling doThisAlways()\n");

     if(dir==1)
     {
        if(offset==500)
        {
           dir=0;
        }
        offset+=2.5;
     }
     else if(dir==0)
     {
         if(offset==0)
         {
            dir=1;
         }
         offset-=2.5;
     }

     glutPostRedisplay();
}

int main()
{
	// GLUT initialization.
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
	glutInitWindowSize(width, height);
	glutCreateWindow("GLUT Skeleton Program");

	// Register call backs.
	glutDisplayFunc(display);
	glutReshapeFunc(reshapeMainWindow);
	glutKeyboardFunc(graphicKeys);
    glutSpecialFunc(functionKeys);
    glutPassiveMotionFunc(mouseMovement);
    glutMouseFunc(mouseAction);
    glutIdleFunc(doThisAlways);
    glutTimerFunc(500, timer, 0);

	// Enter GLUT loop.
	glutMainLoop();
	return 0;
}