/*************************************************************/
/* */
/* Lazer Command video handler */
/* */
/*************************************************************/
#include "emu.h"
#include "includes/lazercmd.h"
/* scale a markers vertical position */
/* the following table shows how the markers */
/* vertical position worked in hardware */
/* marker_y lines marker_y lines */
/* 0 0 + 1 8 10 + 11 */
/* 1 2 + 3 9 12 + 13 */
/* 2 4 + 5 10 14 + 15 */
/* 3 6 + 7 11 16 + 17 */
/* 4 8 + 9 12 18 + 19 */
static int vert_scale(int data)
{
return ((data & 0x07) << 1) + ((data & 0xf8) >> 3) * VERT_CHR;
}
/* plot a bitmap marker */
/* hardware has 2 marker sizes 2x2 and 4x2 selected by jumper */
/* meadows lanes normaly use 2x2 pixels and lazer command uses either */
static void plot_pattern( running_machine &machine, bitmap_t *bitmap, int x, int y )
{
int xbit, ybit, size;
size = 2;
if (input_port_read(machine, "DSW") & 0x40)
{
size = 4;
}
for (ybit = 0; ybit < 2; ybit++)
{
if (y + ybit < 0 || y + ybit >= VERT_RES * VERT_CHR)
return;
for (xbit = 0; xbit < size; xbit++)
{
if (x + xbit < 0 || x + xbit >= HORZ_RES * HORZ_CHR)
continue;
*BITMAP_ADDR16(bitmap, y + ybit, x + xbit) = 4;
}
}
}
SCREEN_UPDATE( lazercmd )
{
lazercmd_state *state = screen->machine().driver_data<lazercmd_state>();
int i, x, y;
int video_inverted = input_port_read(screen->machine(), "DSW") & 0x20;
/* The first row of characters are invisible */
for (i = 0; i < (VERT_RES - 1) * HORZ_RES; i++)
{
int sx, sy;
sx = i % HORZ_RES;
sy = i / HORZ_RES;
sx *= HORZ_CHR;
sy *= VERT_CHR;
drawgfx_opaque(bitmap, cliprect,screen->machine().gfx[0],
state->m_videoram[i], video_inverted ? 1 : 0,
0,0,
sx,sy);
}
x = state->m_marker_x - 1; /* normal video lags marker by 1 pixel */
y = vert_scale(state->m_marker_y) - VERT_CHR; /* first line used as scratch pad */
plot_pattern(screen->machine(), bitmap, x, y);
return 0;
}