//-------------------------------------------------------------------
//	gpmslide.cpp
//
//	programmer: ALLAN CRUSE
//	written on: 21 AUG 2003
//	revised on: 22 OCT 2003
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <fcntl.h>	// for open() 
#include <stdlib.h>	// for exit() 
#include <unistd.h>	// for close() 
#include <termios.h>	// for tcgetattr(), tcsetattr() 
#include <sys/mman.h>	// for mmap() 
#include <sys/io.h>	// for iopl() 
#include <gpm.h>	// for Gpm_Open()

#define VRAM_BASE_ADDRESS 0xA0000000 
#define VGA_MEMORY_LENGTH ( 4 << 20) 
#define ESCAPE_KEY 0x1B

unsigned char *vram = (unsigned char*)VRAM_BASE_ADDRESS; 
const int display_mode = 0x4101, hres = 640, vres = 480; 

// global variables (for control of the slider)
int	minx = 100, maxx = 340, locy = 236;
int	wide = 200, high = 8, bgcolor = 0;
int	curr = 220, prev = 220, fgcolor = 10;

void draw_rectangle( int x, int y, int h, int v, int color ) 
{
	int	minx = 0, miny = 0, maxx = hres-1, maxy = vres-1; 

	do { vram[ y*hres + x ] = color; ++x; } while ( x < maxx ); 
	do { vram[ y*hres + x ] = color; ++y; } while ( y < maxy ); 
	do { vram[ y*hres + x ] = color; --x; } while ( x > minx ); 
	do { vram[ y*hres + x ] = color; --y; } while ( y > miny ); 
}

void fill_rectangle( int x, int y, int h, int v, int color )
{
	int	minx = x, maxx = x+h-1, miny = y, maxy = y+v-1;

	for (y = miny; y <= maxy; y++) 
		for (x = minx; x <= maxx; x++)
			vram[ y*hres + x ] = color;
}	

int map_system_memory( int base, int size ) 
{
	int	fd = open( "/dev/vram", O_RDWR ); 
	if ( fd < 0 ) { perror( "/dev/vram" ); return -1; } 
	int	prot = PROT_READ | PROT_WRITE; 
	int	flag = MAP_FIXED | MAP_SHARED; 
	void	*mm = (void*)base; 
	if ( mmap( mm, size, prot, flag, fd, 0 ) == MAP_FAILED ) 
		{ perror( "mmap" ); return -1; } 
	close( fd ); 
}


int my_handler( Gpm_Event *evt, void *data )
{
	if ( evt->type != GPM_MOVE ) return 0;
	
	prev = curr;
	curr += 2*evt->dx;

	if ( curr < minx ) curr = minx;	
	if ( curr > maxx ) curr = maxx;	

	if ( curr != prev ) 
		{
		fill_rectangle( prev, locy, wide, high, bgcolor );
		fill_rectangle( curr, locy, wide, high, fgcolor );
		}
	return	0;
}	


int main( void )
{
	if ( iopl( 3 ) ) { perror( "iopl" ); exit(1); }
	system( "/sbin/insmod vram.o" ); 
	map_system_memory( VRAM_BASE_ADDRESS, VGA_MEMORY_LENGTH ); 

	struct termios	otty; 
	tcgetattr( 0, &otty ); 
	struct termios	tty = otty; 
	tty.c_lflag &= ~( ICANON | ECHO | ISIG ); 
	tty.c_cc[ VMIN ] = 1; 
	tty.c_cc[ VTIME ] = 0; 
	tcsetattr( 0, TCSAFLUSH, &tty ); 

	char	command[ 40 ]; 
	sprintf( command, " clear ; mode3 %d ", display_mode ); 
	system( command ); 

	int	bordercolor = 15; 
	draw_rectangle( 0, 0, hres, vres, bordercolor ); 
	fill_rectangle( curr, locy, wide, high, fgcolor );

	Gpm_Connect	conn;
	conn.eventMask = ~0;	
	conn.defaultMask = 0;
	conn.minMod = 0;
	conn.maxMod = ~0;
	if ( Gpm_Open( &conn, 0 ) != -1 ) 
		{
		int	c;
		gpm_handler = my_handler;
		while ( ( c = Gpm_Getc( stdin ) ) != ESCAPE_KEY );
		Gpm_Close();
		}
	
	system( " mode3 3 " ); 
	tcsetattr( 0, TCSAFLUSH, &otty ); 
}