/***************************************************************************
video.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
static UINT8 background_image;
static tilemap *fg_tilemap, *bg_tilemap;
WRITE8_HANDLER( bombjack_videoram_w )
{
videoram[offset] = data;
tilemap_mark_tile_dirty(fg_tilemap, offset);
}
WRITE8_HANDLER( bombjack_colorram_w )
{
colorram[offset] = data;
tilemap_mark_tile_dirty(fg_tilemap, offset);
}
WRITE8_HANDLER( bombjack_background_w )
{
if (background_image != data)
{
background_image = data;
tilemap_mark_all_tiles_dirty(bg_tilemap);
}
}
WRITE8_HANDLER( bombjack_flipscreen_w )
{
if (flip_screen != (data & 0x01))
{
flip_screen_set(data & 0x01);
tilemap_mark_all_tiles_dirty(ALL_TILEMAPS);
}
}
static TILE_GET_INFO( get_bg_tile_info )
{
UINT8 *tilerom = memory_region(REGION_GFX4);
int offs = (background_image & 0x07) * 0x200 + tile_index;
int code = (background_image & 0x10) ? tilerom[offs] : 0;
int attr = tilerom[offs + 0x100];
int color = attr & 0x0f;
int flags = (attr & 0x80) ? TILE_FLIPY : 0;
SET_TILE_INFO(1, code, color, flags);
}
static TILE_GET_INFO( get_fg_tile_info )
{
int code = videoram[tile_index] + 16 * (colorram[tile_index] & 0x10);
int color = colorram[tile_index] & 0x0f;
SET_TILE_INFO(0, code, color, 0);
}
VIDEO_START( bombjack )
{
bg_tilemap = tilemap_create(get_bg_tile_info, tilemap_scan_rows,
TILEMAP_TYPE_PEN, 16, 16, 16, 16);
fg_tilemap = tilemap_create(get_fg_tile_info, tilemap_scan_rows,
TILEMAP_TYPE_PEN, 8, 8, 32, 32);
tilemap_set_transparent_pen(fg_tilemap, 0);
state_save_register_global(background_image);
}
static void draw_sprites(running_machine *machine, mame_bitmap *bitmap, const rectangle *cliprect)
{
int offs;
for (offs = spriteram_size - 4; offs >= 0; offs -= 4)
{
/*
abbbbbbb cdefgggg hhhhhhhh iiiiiiii
a use big sprites (32x32 instead of 16x16)
bbbbbbb sprite code
c x flip
d y flip (used only in death sequence?)
e ? (set when big sprites are selected)
f ? (set only when the bonus (B) materializes?)
gggg color
hhhhhhhh x position
iiiiiiii y position
*/
int sx,sy,flipx,flipy;
sx = spriteram[offs+3];
if (spriteram[offs] & 0x80)
sy = 225-spriteram[offs+2];
else
sy = 241-spriteram[offs+2];
flipx = spriteram[offs+1] & 0x40;
flipy = spriteram[offs+1] & 0x80;
if (flip_screen)
{
if (spriteram[offs+1] & 0x20)
{
sx = 224 - sx;
sy = 224 - sy;
}
else
{
sx = 240 - sx;
sy = 240 - sy;
}
flipx = !flipx;
flipy = !flipy;
}
drawgfx(bitmap,machine->gfx[(spriteram[offs] & 0x80) ? 3 : 2],
spriteram[offs] & 0x7f,
spriteram[offs+1] & 0x0f,
flipx,flipy,
sx,sy,
cliprect,TRANSPARENCY_PEN,0);
}
}
VIDEO_UPDATE( bombjack )
{
tilemap_draw(bitmap, cliprect, bg_tilemap, 0, 0);
tilemap_draw(bitmap, cliprect, fg_tilemap, 0, 0);
draw_sprites(machine, bitmap, cliprect);
return 0;
}