/***************************************************************************
video/aeroboto.c
***************************************************************************/
#include "emu.h"
#include "includes/aeroboto.h"
// how the starfield ROM is interpreted: 0=256x256x1 linear bitmap, 1=8x8x1x1024 tilemap
#define STARS_LAYOUT 1
// scroll speed of the stars: 1=normal, 2=half, 3=one-third...etc.(possitive integers only)
#define SCROLL_SPEED 1
/***************************************************************************
Callbacks for the TileMap code
***************************************************************************/
static TILE_GET_INFO( get_tile_info )
{
aeroboto_state *state = machine.driver_data<aeroboto_state>();
UINT8 code = state->m_videoram[tile_index];
SET_TILE_INFO(
0,
code + (state->m_charbank << 8),
state->m_tilecolor[code],
(state->m_tilecolor[code] >= 0x33) ? 0 : TILE_FORCE_LAYER0);
}
// transparency should only affect tiles with color 0x33 or higher
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
VIDEO_START( aeroboto )
{
aeroboto_state *state = machine.driver_data<aeroboto_state>();
state->m_bg_tilemap = tilemap_create(machine, get_tile_info, tilemap_scan_rows, 8, 8, 32, 64);
tilemap_set_transparent_pen(state->m_bg_tilemap, 0);
tilemap_set_scroll_rows(state->m_bg_tilemap, 64);
state->save_item(NAME(state->m_charbank));
state->save_item(NAME(state->m_starsoff));
state->save_item(NAME(state->m_sx));
state->save_item(NAME(state->m_sy));
state->save_item(NAME(state->m_ox));
state->save_item(NAME(state->m_oy));
#if STARS_LAYOUT
{
UINT8 *temp;
int i;
temp = auto_alloc_array(machine, UINT8, state->m_stars_length);
memcpy(temp, state->m_stars_rom, state->m_stars_length);
for (i = 0; i < state->m_stars_length; i++)
state->m_stars_rom[(i & ~0xff) + (i << 5 & 0xe0) + (i >> 3 & 0x1f)] = temp[i];
auto_free(machine, temp);
}
#endif
}
/***************************************************************************
Memory handlers
***************************************************************************/
READ8_HANDLER( aeroboto_in0_r )
{
return input_port_read(space->machine(), flip_screen_get(space->machine()) ? "P2" : "P1");
}
WRITE8_HANDLER( aeroboto_3000_w )
{
aeroboto_state *state = space->machine().driver_data<aeroboto_state>();
/* bit 0 selects both flip screen and player1/player2 controls */
flip_screen_set(space->machine(), data & 0x01);
/* bit 1 = char bank select */
if (state->m_charbank != ((data & 0x02) >> 1))
{
tilemap_mark_all_tiles_dirty(state->m_bg_tilemap);
state->m_charbank = (data & 0x02) >> 1;
}
/* bit 2 = disable star field? */
state->m_starsoff = data & 0x4;
}
WRITE8_HANDLER( aeroboto_videoram_w )
{
aeroboto_state *state = space->machine().driver_data<aeroboto_state>();
state->m_videoram[offset] = data;
tilemap_mark_tile_dirty(state->m_bg_tilemap,offset);
}
WRITE8_HANDLER( aeroboto_tilecolor_w )
{
aeroboto_state *state = space->machine().driver_data<aeroboto_state>();
if (state->m_tilecolor[offset] != data)
{
state->m_tilecolor[offset] = data;
tilemap_mark_all_tiles_dirty(state->m_bg_tilemap);
}
}
/***************************************************************************
Display refresh
***************************************************************************/
static void draw_sprites( running_machine &machine, bitmap_t *bitmap, const rectangle *cliprect )
{
aeroboto_state *state = machine.driver_data<aeroboto_state>();
int offs;
for (offs = 0; offs < state->m_spriteram_size; offs += 4)
{
int x = state->m_spriteram[offs + 3];
int y = 240 - state->m_spriteram[offs];
if (flip_screen_get(machine))
{
x = 248 - x;
y = 240 - y;
}
drawgfx_transpen(bitmap, cliprect, machine.gfx[1],
state->m_spriteram[offs + 1],
state->m_spriteram[offs + 2] & 0x07,
flip_screen_get(machine), flip_screen_get(machine),
((x + 8) & 0xff) - 8, y, 0);
}
}
SCREEN_UPDATE( aeroboto )
{
aeroboto_state *state = screen->machine().driver_data<aeroboto_state>();
static const rectangle splitrect1 = { 0, 255, 0, 39 };
static const rectangle splitrect2 = { 0, 255, 40, 255 };
UINT8 *src_base, *src_colptr, *src_rowptr;
int src_offsx, src_colmask, sky_color, star_color, x, y, i, j, pen;
sky_color = star_color = *state->m_bgcolor << 2;
// the star field is supposed to be seen through tile pen 0 when active
if (!state->m_starsoff)
{
if (star_color < 0xd0)
{
star_color = 0xd0;
sky_color = 0;
}
star_color += 2;
bitmap_fill(bitmap, cliprect, sky_color);
// actual scroll speed is unknown but it can be adjusted by changing the SCROLL_SPEED constant
state->m_sx += (char)(*state->m_starx - state->m_ox);
state->m_ox = *state->m_starx;
x = state->m_sx / SCROLL_SPEED;
if (*state->m_vscroll != 0xff)
state->m_sy += (char)(*state->m_stary - state->m_oy);
state->m_oy = *state->m_stary;
y = state->m_sy / SCROLL_SPEED;
src_base = state->m_stars_rom;
for (i = 0; i < 256; i++)
{
src_offsx = (x + i) & 0xff;
src_colmask = 1 << (src_offsx & 7);
src_offsx >>= 3;
src_colptr = src_base + src_offsx;
pen = star_color + ((i + 8) >> 4 & 1);
for (j = 0; j < 256; j++)
{
src_rowptr = src_colptr + (((y + j) & 0xff) << 5 );
if (!((unsigned)*src_rowptr & src_colmask))
*BITMAP_ADDR16(bitmap, j, i) = pen;
}
}
}
else
{
state->m_sx = state->m_ox = *state->m_starx;
state->m_sy = state->m_oy = *state->m_stary;
bitmap_fill(bitmap, cliprect, sky_color);
}
for (y = 0; y < 64; y++)
tilemap_set_scrollx(state->m_bg_tilemap, y, state->m_hscroll[y]);
// the playfield is part of a splitscreen and should not overlap with status display
tilemap_set_scrolly(state->m_bg_tilemap, 0, *state->m_vscroll);
tilemap_draw(bitmap, &splitrect2, state->m_bg_tilemap, 0, 0);
draw_sprites(screen->machine(), bitmap, cliprect);
// the status display behaves more closely to a 40-line splitscreen than an overlay
tilemap_set_scrolly(state->m_bg_tilemap, 0, 0);
tilemap_draw(bitmap, &splitrect1, state->m_bg_tilemap, 0, 0);
return 0;
}