/*
** Name:      Colourlist Example
** Author:    Adam Dawes and Paul Manias
** Copyright: DreamWorld Productions (c) 1996.  Freely Distributable.
** SAS/C:     1> sc ColourBars.c link startup=LIB:gms.o data=far nostackcheck
**  Dice:     1> dcc -l0 -mD gms.o ColourBars.c -o ColourBars
**
** Colourlists are those nice colour gradients used in demos and games,
** usually  sitting in the background of your screen.  Colourlists are mostly
** good for getting more colours on screen than what is really available.
** Although  GMS allows you to do other screen effects based on raster lines,
** we'll just stick to changing colours in this demo.
** 
** You can move the green colour bar by moving the mouse up and down.
** You will notice that if you move the green bar into the upper red bar,
** your bar will disappear and leave some green lines at the end of the red
** bar.  This is because:
** 
**   WAITLINE  95        ;Wait for line 95
**   WAITLINE 100        ;Wait for line 100
**   WAITLINE  90        ;Wait for line 90 <--Error! 
** 
** Is illegal.  The monitor beam travels down the screen, and so the
** UpdateRasterlist() routine will expect all lines to be in sequential order.
** Moving two colourbars into each other breaks this rule, causing the wait
** command to be ignored.  If you want to get around this (green bar appears
** on top of red bar), you will have to have just one large colourlist and
** sort your colours before each call to UpdateRasterlist().
** 
** Similarly if you move the colour bar too far down the screen the hardware
** won't like it because lines > 311 don't exist.  It's up to you to be
** responsible enough to stop this from happening!
** 
** Press the left mouse button to exit the demo.
*/

#include <proto/games.h>

extern struct GMSBase *GMSBase;
APTR   PREFSNAME = DEFAULT;

LONG ColourBar1[] = {
     0x100000,0x200000,0x300000,0x400000,0x500000,0x600000,0x700000,0x800000,0x900000,0xa00000,
     0xb00000,0xc00000,0xd00000,0xe00000,0xe00000,0xe00000,0xd00000,0xc00000,0xb00000,0xa00000,
     0x900000,0x800000,0x700000,0x600000,0x500000,0x400000,0x300000,0x200000,0x100000,0x000000,
     -1
};

LONG ColourBar2[] = {
     0x001000,0x002000,0x003000,0x004000,0x005000,0x006000,0x007000,0x008000,0x009000,0x00a000,
     0x00b000,0x00c000,0x00d000,0x00e000,0x00f000,0x00e000,0x00d000,0x00c000,0x00b000,0x00a000,
     0x009000,0x008000,0x007000,0x006000,0x005000,0x004000,0x003000,0x002000,0x001000,0x000000,
     -1
};

LONG ColourBar3[] = {
     0x000010,0x000020,0x000030,0x000040,0x000050,0x000060,0x000070,0x000080,0x000090,0x0000a0,
     0x0000b0,0x0000c0,0x0000d0,0x0000e0,0x0000f0,0x0000e0,0x0000d0,0x0000c0,0x0000b0,0x0000a0,
     0x000090,0x000080,0x000070,0x000060,0x000050,0x000040,0x000030,0x000020,0x000010,0x000000,
     -1
};

ULONG Rasterlist[] = {
     COLOURLIST(000,3,00,&ColourBar1),   /* Line, Skip, Colnum, ColourList */
     COLOURLIST(160,1,00,&ColourBar2),   /* Line, Skip, Colnum, ColourList */
     COLOURLIST(230,1,00,&ColourBar3),   /* Line, Skip, Colnum, ColourList */
     RASTEND
};

void main(void)
{
   struct GameScreen *GameScreen;
   WORD   barpos = 160;
   ULONG  mouse;

   if (GameScreen = AddScreenTags(TAGS_GAMESCREEN,NULL,
       GSA_Rasterlist,&Rasterlist,
       GSA_Planes,1,
       GSA_Attrib,BLKBDR,
       TAGEND)) {

      ShowScreen(GameScreen);
      InitJoyPorts();

      do {
         mouse = ReadJoyPort(JPORT1,JT_ZBXY);
         barpos += (BYTE)mouse;
         if (barpos < 0) barpos = 0;
         if (barpos > 226) barpos = 226;
         Rasterlist[4] = (Rasterlist[4] & 0xffff0000)|barpos;
         UpdateRasterLines(GameScreen);
         WaitVBL();
      } while (!(mouse & MB_LMB));

   DeleteScreen(GameScreen);
   }
}