//
////////////////////////////////////////////////////////

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

#define DRAW_POINT 1

int drawing_mode = 1;

int width=500, height = 500; // display window width and height

int press_x, press_y;
int release_x, release_y;

int   type_list[200];       // primitive buffer
                            // 200: max number of primitives allowed
float vertex_list_x[1000];  // x buffer
float vertex_list_y[1000];  // y buffer

int   nop = 0; // number of primitives
int   nov = 0; // number of vertices

/////////////////////////////////////////////

void display_all()
{
  float x, y;
  int p_idx, next_primitive; int v_idx = 0;

  if (nop!=0) {  // there primitive buffer is not empty

    for (p_idx = 0; p_idx <nop; p_idx++) {

      next_primitive = type_list[p_idx];

      if (next_primitive==1) glColor3f(1,1,1);     // point: white

      if (next_primitive==1){
		glPointSize(3);
		glBegin(GL_POINTS);
		  x = vertex_list_x[v_idx];
		  y = vertex_list_y[v_idx];
		  glVertex2f(x,y);
		glEnd();
		glPointSize(1);
		v_idx++;
      }
      glFlush();  // force OpenGL to draw all the objects 
    }
  }
}

/////////////////////////////////////////////

void display()
{
  // clear the screen
  glClearColor(0,0,0,1);  //  background color - black
  glClear(GL_COLOR_BUFFER_BIT);

  // set the world window
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluOrtho2D(0, 499, 0, 499);  // here I just hard-wire the world window 

  // now call the real drawing function
  display_all();

}

//////////////////////////////////////////////////
//
//  The callback functions
//
//////////////////////////////////////////////////

void mymouse(int button, int state, int x, int y)
{
  if (drawing_mode == DRAW_POINT){
    if (state == GLUT_UP) {
      // insert to both the primitive and vertex buffers
      type_list[nop++] = 1; // 1: point
      vertex_list_x[nov] = x;
      vertex_list_y[nov++] = height - y;  // GLUT and GL define the
                                          // origin at different positions
    }
  }
  glutPostRedisplay(); // now display everything in the buffers
}

void mymenu(int value){
  if (value == 1) drawing_mode = DRAW_POINT;
}

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

////////////////////////////////////////////////////

void resize(int w, int h)
{
  // this is really just the default GLUT behavior. you should change it for the lab1
  glViewport(0,0,w,h); 
  glutPostRedisplay(); 
}

////////////////////////////////////////////////////
void myInit() {
  // did not really do much here 
  // set the viewport
  glViewport(0,0,width, height);
}


//////////////////////////////////////////////////////////

int main(int argc, char** argv)
{
  // init glut drawing window
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_RGB|GLUT_SINGLE);
  glutInitWindowSize(width,height);
  glutCreateWindow("Han-Wei Shen's simple program");

  myInit();   // my own OpenGL initialization

  // register callbacks
  glutDisplayFunc(display);
  glutReshapeFunc(resize);
  glutMouseFunc(mymouse);
  glutKeyboardFunc(mykey);

  // create menu
  glutCreateMenu(mymenu);
  glutAddMenuEntry("Point", 1);
  glutAttachMenu(GLUT_RIGHT_BUTTON);

  // enter the event loop
  glutMainLoop();
}