// copyright Min Zhong, cs838 proj2, April, 2000


// $Header: /p/graphics/CVS/638/Web/Examples/GL/RunButton.cpp,v 1.1 1999/10/20 16:25:05 gleicher Exp $
//
// CS638 Example code - this provides a utility routine to help with animation
// written October, 1999 by Michael L. Gleicher
//
// This file implements a "play" button. The idea is that you creat a window that
// does your drawing. When redrawing, this window looks at a slider to see what
// time it is, so it knows what part of the animation to draw.
//
// The slider must call the window's redraw function whenever the time changes.
//
// The play button, when pressed, advances the slider forward a timestep continually.
// In order to do this, it installs itself in the FlTk "Idle" loop so it gets called
// periodically.
//

#include "RunButton.H"
#include "viewer.h"


// this is the regular fltk callback for run button
void runCB(Fl_Widget* wid, Fl_Widget* o)
{
	o->damage(1);
}



// the slider constructor
RunSlider::RunSlider(Fl_Widget* dr, int length,
					 int x, int y, int w, int h) : Fl_Value_Slider(x,y,w,h)
{

	// set up slider parameters
	value(0);
	range(0,length-1);
	step(1);
	type(5);				// horizontal, "nice"
	when(FL_WHEN_CHANGED);	// update whenever it changes

	callback((Fl_Callback*) runSliderCB, dr);
}


// 
// this callback function is the "guts" of the RunButton -
// notice that it is an "idle" callback, not a widget callback
//
// another nice problem to have - most likely, we'll be too fast
// don't draw more than 30 times per second
void runButtonCB(RunButton* b)
{
	int cur_ticks	= (int) clock();	// cur time in ticks

	if (b->value()) {	// only advance time if appropriate

		long ticks_so_far = (cur_ticks - b->firstRedraw) % (long) (b->ticks_tot);
		long ticks_since_last = (cur_ticks - b->lastRedraw);
		int	frame_to_draw;

			// need to draw a frame
		if (b->mode == REAL_TIME) {
			if ( ticks_since_last > b->ticks_per_frame) {
		
				b->lastRedraw	= cur_ticks;	// update lastRedraw time
				frame_to_draw	= (int) (ticks_so_far / b->ticks_tot * b->frame_cnt)
							+ (int) b->slider->minimum();
				b->slider->value(frame_to_draw);
				// when the value is changed internally
				(b->slider->callback())(b->slider,b->slider->user_data());
	
			}
		}
		else if (b->mode == CONST_SPD) {
			if ( ticks_since_last > CLOCKS_PER_SEC / 30) {

				int frame_max = (int) b->slider->maximum();				
				frame_to_draw = (int) b->slider->value();
				frame_to_draw ++;
				if (frame_to_draw > frame_max) 
					frame_to_draw = (int) b->slider->minimum();	// wrap around

				b->slider->value(frame_to_draw);
				// note: FlTk doesn't have the slider call its callback
				// when the value is changed internally
				(b->slider->callback())(b->slider,b->slider->user_data());
			}
		} // if need to draw
	}
}

// create the run button - the main thing it does is install the idle
// handler
RunButton::RunButton(Fl_Slider* timeS, 
					 int x, int y, int w, int h, 
					 double in_frame_time, PLAYMODE in_mode)
					 : Fl_Light_Button(x,y,w,h,"Play")
{
	slider = timeS;
	init_ticks(in_frame_time, in_mode);
}


// init tick counters, called every time a new first motion file loaded
RunButton::init_ticks(double in_frame_time, PLAYMODE in_mode)
{
	Fl::remove_idle((void (*)(void*))runButtonCB,this);

	lastRedraw	= 0;
	firstRedraw = 0;
	ticks_per_frame = (in_frame_time * CLOCKS_PER_SEC);
	frame_cnt	= ((int) slider->maximum() - (int)slider->minimum() + 1);
	ticks_tot	= ticks_per_frame * frame_cnt;
	mode		= in_mode;

	Fl::add_idle((void (*)(void*))runButtonCB,this);

}


RunButton::~RunButton()
{
	Fl::remove_idle((void (*)(void*))runButtonCB,this);
}