/*
 * Copyright (c) 2002-2004, Adam Dunkels.
 * All rights reserved. 
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met: 
 * 1. Redistributions of source code must retain the above copyright 
 *    notice, this list of conditions and the following disclaimer. 
 * 2. Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials provided
 *    with the distribution. 
 * 3. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior
 *    written permission.  
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  
 *
 * This file is part of the Contiki desktop environment
 *
 * $Id: ssfire.c,v 1.1 2006/06/17 22:41:25 adamdunkels Exp $
 *
 */

#include <stdlib.h>

#include "ctk/ctk.h"
#include "ctk/ctk-draw.h"
#include "ctk/ctk-mouse.h"
#include "contiki.h"
#include "sys/loader.h"

PROCESS(ssfire_process, "Fire screensaver");

static unsigned char flames[8*17];


static const unsigned char flamecolors[16] =
  {COLOR_BLACK,    COLOR_BLACK,  COLOR_BLACK, COLOR_RED,
   COLOR_LIGHTRED, COLOR_YELLOW, COLOR_WHITE, COLOR_WHITE,
   COLOR_WHITE,    COLOR_WHITE,  COLOR_WHITE, COLOR_WHITE,
   COLOR_WHITE,    COLOR_WHITE,  COLOR_WHITE, COLOR_WHITE};
   

/*---------------------------------------------------------------------------*/
static void
fire_init(void)
{
  unsigned char *ptr, *cptr;
  
  /* Fill screen with inverted spaces. */
  cptr = COLOR_RAM;
  for(ptr = (unsigned char *)0x0400;
      ptr != (unsigned char *)0x07e8;
      ++ptr) {
    *ptr = 0xa0;
    *cptr++ = 0x00;
  }

  SID.v3.freq = 0xffff;
  SID.v3.ctrl = 0x80;
  SID.amp = 0;  

  VIC.ctrl1 = 0x1b;  /* $D011 */
  VIC.addr  = 0x17;  /* $D018 */
  VIC.ctrl2 = 0xc8;  /* $D016 */
  VIC.bordercolor = 0x00; /* $D020 */
  VIC.bgcolor0 = 0x00; /* $D021 */  
  CIA2.pra  = 0x03;  /* $DD00 */
}
/*---------------------------------------------------------------------------*/
#pragma optimize(push, off)
static void
fire_burn(void)
{
  /* Calculate new flames. */
  asm("ldy #$00");
loop1:
  asm("lda %v+7,y", flames);
  asm("clc");
  asm("adc %v+8,y", flames);
  asm("adc %v+9,y", flames);
  asm("adc %v+16,y", flames);
  asm("lsr");
  asm("lsr");
  asm("sta %v,y", flames);
  asm("iny");
  asm("cpy #(8*15)");
  asm("bne %g", loop1);

  /* Fill last line with pseudo-random data from noise generator on
     voice 3. */
  asm("ldy #$05");
loop2:
  asm("ldx #$20");
delay:
  asm("dex");
  asm("bne %g", delay);
  asm("lda $D41B");
  asm("and #$0F");
  asm("sta %v+8*15+1,y", flames);
  asm("dey");
  asm("bpl %g", loop2);
}
#pragma optimize(pop)
/*---------------------------------------------------------------------------*/
static unsigned char *flameptr, *colorptr1, *colorptr2;
static unsigned char x, y;

static void
pollhandler(void)
{

  if(ctk_mode_get() == CTK_MODE_SCREENSAVER) {
  
    fire_burn();
  
    /* Display flames on screen. */  
    flameptr = flames;
    colorptr1 = COLOR_RAM + 40*10;
    colorptr2 = colorptr1 + 0x20;
    for(y = 0; y < 15; ++y) {
      for(x = 0; x < 8; ++x) {
	colorptr1[x] = colorptr2[x] = flamecolors[flameptr[x]];
      }
      colorptr1 += 0x28;
      colorptr2 += 0x28;
      flameptr += 8;
    }
  }
}
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(ssfire_process, ev, data)
{
  PROCESS_POLLHANDLER(pollhandler());
  
  PROCESS_BEGIN();
  
  ctk_mode_set(CTK_MODE_SCREENSAVER);
  ctk_mouse_hide();
  fire_init();

  
  PROCESS_WAIT_EVENT_UNTIL(ev == ctk_signal_screensaver_stop ||
			   ev == PROCESS_EVENT_EXIT);

  ctk_draw_init();
  ctk_desktop_redraw(NULL);

  PROCESS_END();
}
/*---------------------------------------------------------------------------*/