/*****************************************************************************
             Main Program for CS480 Programming Assignment 2
******************************************************************************
    Author: Stan Sclaroff
            Boston University Computer Science Dept.
            February 15, 1995
******************************************************************************
Description: 
             This is the main program for the transformer program assignment.
	     It opens a GL window in double buffer mode, and opens a slider
	     menu for controlling the transforms. 

             The user interface is through a separate slider menu
             which controls the rotation, translation, scaling,
             shearing, bending of a shape that's been defined as a
             polyline.

	     There are also three main buttons on the slider menu:

	      RESET SLIDERS:  sets sliders all to default values and redraw.
	      PLAY: This button is provided for you to play your animation.
	      QUIT: This button allows you to exit.

	     In addition, there are separate reset buttons for each slider.


******************************************************************************
Comments:    This program has an optional command-line argument for specifying
	     a polyline text file.  For instance, typing

	     animate figure.poly 

	     will load in the polylines contained in the text file "figure.poly"
******************************************************************************/

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <gl/gl.h>
#include <gl/device.h>
#include "forms.h"
#include "menu.h"
#include "draw.h"

/* global variables !!! These are used by the menu call backs */

Polyline *figure;   /* the polyline figure drawn */
Frame *frame;       /* the rectangular clipping frame */
long winid;         /* the drawing window id */

/* these globals are for the sliders themselves */
float slider_values[NUM_SLIDERS] = {0.0,0.0,0.0,100.0,100.0,
				      0.0,0.0,0.0,0.0};

/* the slider default values */
float slider_default_values[NUM_SLIDERS] = {0.0,0.0,0.0,100.0,100.0,
					    0.0,0.0,0.0,0.0};

/* the slider min/max values */
float slider_min_values[NUM_SLIDERS] = {0.0,
					  -SCREEN_WIDTH/2,-SCREEN_HEIGHT/2,
					  0.0,0.0,
					  -5.0,-5.0,
					  -5.0,-5.0};

float slider_max_values[NUM_SLIDERS] = {360.0,
					  SCREEN_WIDTH/2,SCREEN_HEIGHT/2,
					  SCREEN_WIDTH,SCREEN_HEIGHT,
					  5.0,5.0,
					  5.0,5.0};


/* the animation tool's main program */
main(argc, argv)
int argc;
char **argv;
{
  int i,j;
  float w,h,min_x,min_y,max_x,max_y,x,y;
  Device event;
  Screencoord mouse_pos[2];

  /* a polyline file can be specified as an input argument */
  if(argc > 1)
    figure = read_polyline_file(argv[1],YELLOW);

  /* if none is provided, use default: a box */
  else
    figure = read_polyline_file("box.poly",YELLOW);
    
  /* failed to open a polyline file, so close up */
  if(figure == 0)
    exit(EXIT_SUCCESS);

  /* create the clipping frame */
  frame = create_frame((float)FRAME_XMIN,(float)FRAME_YMIN,(float)FRAME_XMAX,(float)FRAME_YMAX,RED);

  /* open the menu forms: slider window */
  create_the_forms();  

  /* open the GL graphics window */
  winid = open_window(SCREEN_WIDTH,SCREEN_HEIGHT,"Animation Window"); 

  /* set up the sliders on the slider menu and then activate them */
  setup_sliders();
  activate_forms();

  /* first time around draw twice: once to the front buffer and then
     once to the back buffer...this buffer switching happens
     automatically */

  redraw(winid,figure,slider_values,frame);
  redraw(winid,figure,slider_values,frame);

  /* the inner loop: let the slider menu take control */
  do
    fl_check_forms();      
  while(TRUE);

}

/* the call back routine for playing an animation */
/* this routine gets called every time the "play" button */
/* on the menu is pressed */
#define T_STEP 0.1
#define TOLERANCE 0.001
#define DAMPING_FACTOR 0.04
#define AMPLITUDE 5.0

void playCB(obj,arg)
FL_OBJECT *obj;
long arg;
{
  float theta,val,t,dt,d_theta,vale;
  int i;

  for(i=0;i<NUM_SLIDERS;++i)
    slider_values[i] = slider_default_values[i];

  dt = T_STEP;
  d_theta = PI/dt;
  val = 1.0;
  for(theta=t=0.0;fabs(val)>TOLERANCE;t+=dt,theta+=d_theta)
    {
      val = AMPLITUDE*cos(t)*exp(-t*t*DAMPING_FACTOR);
      slider_values[BEND_Y] = val;
      slider_values[TRANSLATE_Y] += val;
      redraw(winid,figure,slider_values,frame);
    }
      
}

/* the call back routine for quiting the program */
/* gets called when the quit button is pushed */
void quitCB(obj,arg)
FL_OBJECT *obj;
long arg;
{
  /* cleanup */
  free_polyline(figure);
  free_frame(frame);
  close_window(winid);

  exit(EXIT_SUCCESS);
}
  
/* this routine sets up the sliders default and min/max values */
void setup_sliders()
{
  int i;

  /* set each slider's default value and min/max */
  for(i=0;i<NUM_SLIDERS;++i)
    {
      fl_set_slider_bounds(sliders[i],slider_min_values[i],slider_max_values[i]);
      fl_set_slider_step(sliders[i],0.25);
      slider_values[i] = slider_default_values[i];
      fl_set_slider_value(sliders[i],slider_default_values[i]);
    }
}

/* the call back routine for moving a slider */
void sliderCB(obj,arg)
FL_OBJECT *obj;
long arg;
{
  /* get the new slider value, and then redraw */
  slider_values[arg] = fl_get_slider_value(sliders[arg]);
  redraw(winid,figure,slider_values,frame);
}

/* reset all the sliders to their default value */
void resetslidersCB(obj,arg)
FL_OBJECT *obj;
long arg;
{
  int i;

  /* reset all the sliders to their default values */
  for(i=0;i<NUM_SLIDERS;++i)
    {
      fl_set_slider_value(sliders[i],slider_default_values[i]);
      slider_values[i] = slider_default_values[i];
    }
  
  /* redraw */
  redraw(winid,figure,slider_values,frame);
}

/* reset a slider to it's default value */
void resetsliderCB(obj,arg)
FL_OBJECT *obj;
long arg;
{
  /* reset a particular slider  to its default value */
  fl_set_slider_value(sliders[arg],slider_default_values[arg]);
  slider_values[arg] = slider_default_values[arg];
  
  /* redraw */
  redraw(winid,figure,slider_values,frame);
}