/***************************************************************************
video.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
int yiear_nmi_enable;
static tilemap *bg_tilemap;
/***************************************************************************
Convert the color PROMs into a more useable format.
Yie Ar Kung-Fu has one 32x8 palette PROM, connected to the RGB output this
way:
bit 7 -- 220 ohm resistor -- BLUE
-- 470 ohm resistor -- BLUE
-- 220 ohm resistor -- GREEN
-- 470 ohm resistor -- GREEN
-- 1 kohm resistor -- GREEN
-- 220 ohm resistor -- RED
-- 470 ohm resistor -- RED
bit 0 -- 1 kohm resistor -- RED
***************************************************************************/
PALETTE_INIT( yiear )
{
int i;
for (i = 0;i < machine->drv->total_colors;i++)
{
int bit0,bit1,bit2,r,g,b;
/* red component */
bit0 = (*color_prom >> 0) & 0x01;
bit1 = (*color_prom >> 1) & 0x01;
bit2 = (*color_prom >> 2) & 0x01;
r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (*color_prom >> 3) & 0x01;
bit1 = (*color_prom >> 4) & 0x01;
bit2 = (*color_prom >> 5) & 0x01;
g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = 0;
bit1 = (*color_prom >> 6) & 0x01;
bit2 = (*color_prom >> 7) & 0x01;
b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
palette_set_color(machine,i,MAKE_RGB(r,g,b));
color_prom++;
}
}
WRITE8_HANDLER( yiear_videoram_w )
{
videoram[offset] = data;
tilemap_mark_tile_dirty(bg_tilemap, offset / 2);
}
WRITE8_HANDLER( yiear_control_w )
{
/* bit 0 flips screen */
if (flip_screen != (data & 0x01))
{
flip_screen_set(data & 0x01);
tilemap_mark_all_tiles_dirty(ALL_TILEMAPS);
}
/* bit 1 is NMI enable */
yiear_nmi_enable = data & 0x02;
/* bit 2 is IRQ enable */
interrupt_enable_w(0, data & 0x04);
/* bits 3 and 4 are coin counters */
coin_counter_w(0, data & 0x08);
coin_counter_w(1, data & 0x10);
}
static TILE_GET_INFO( get_bg_tile_info )
{
int offs = tile_index * 2;
int attr = videoram[offs];
int code = videoram[offs + 1] | ((attr & 0x10) << 4);
// int color = (attr & 0xf0) >> 4;
int flags = ((attr & 0x80) ? TILE_FLIPX : 0) | ((attr & 0x40) ? TILE_FLIPY : 0);
SET_TILE_INFO(0, code, 0, flags);
}
VIDEO_START( yiear )
{
bg_tilemap = tilemap_create(get_bg_tile_info, tilemap_scan_rows,
TILEMAP_TYPE_PEN, 8, 8, 32, 32);
}
static void draw_sprites(running_machine *machine, mame_bitmap *bitmap, const rectangle *cliprect)
{
int offs;
for (offs = spriteram_size - 2;offs >= 0;offs -= 2)
{
int attr = spriteram[offs];
int code = spriteram_2[offs + 1] + 256 * (attr & 0x01);
int color = 0;
int flipx = ~attr & 0x40;
int flipy = attr & 0x80;
int sy = 240 - spriteram[offs + 1];
int sx = spriteram_2[offs];
if (flip_screen)
{
sy = 240 - sy;
flipy = !flipy;
}
if (offs < 0x26)
{
sy++; /* fix title screen & garbage at the bottom of the screen */
}
drawgfx(bitmap, machine->gfx[1],
code, color,
flipx, flipy,
sx, sy,
cliprect,
TRANSPARENCY_PEN, 0);
}
}
VIDEO_UPDATE( yiear )
{
tilemap_draw(bitmap, cliprect, bg_tilemap, 0, 0);
draw_sprites(machine, bitmap, cliprect);
return 0;
}