/***************************************************************************
video.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "includes/gundealr.h"
/***************************************************************************
Callbacks for the TileMap code
***************************************************************************/
static TILE_GET_INFO( get_bg_tile_info )
{
gundealr_state *state = machine.driver_data<gundealr_state>();
UINT8 attr = state->m_bg_videoram[2 * tile_index + 1];
SET_TILE_INFO(
0,
state->m_bg_videoram[2 * tile_index] + ((attr & 0x07) << 8),
(attr & 0xf0) >> 4,
0);
}
static TILEMAP_MAPPER( gundealr_scan )
{
/* logical (col,row) -> memory offset */
return (row & 0x0f) + ((col & 0x3f) << 4) + ((row & 0x10) << 6);
}
static TILE_GET_INFO( get_fg_tile_info )
{
gundealr_state *state = machine.driver_data<gundealr_state>();
UINT8 attr = state->m_fg_videoram[2 * tile_index + 1];
SET_TILE_INFO(
1,
state->m_fg_videoram[2 * tile_index] + ((attr & 0x03) << 8),
(attr & 0xf0) >> 4,
0);
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
VIDEO_START( gundealr )
{
gundealr_state *state = machine.driver_data<gundealr_state>();
state->m_bg_tilemap = tilemap_create(machine, get_bg_tile_info, tilemap_scan_cols, 8, 8, 32, 32);
state->m_fg_tilemap = tilemap_create(machine, get_fg_tile_info, gundealr_scan, 16, 16, 64, 32);
tilemap_set_transparent_pen(state->m_fg_tilemap, 15);
}
/***************************************************************************
Memory handlers
***************************************************************************/
WRITE8_HANDLER( gundealr_bg_videoram_w )
{
gundealr_state *state = space->machine().driver_data<gundealr_state>();
state->m_bg_videoram[offset] = data;
tilemap_mark_tile_dirty(state->m_bg_tilemap, offset / 2);
}
WRITE8_HANDLER( gundealr_fg_videoram_w )
{
gundealr_state *state = space->machine().driver_data<gundealr_state>();
state->m_fg_videoram[offset] = data;
tilemap_mark_tile_dirty(state->m_fg_tilemap, offset / 2);
}
WRITE8_HANDLER( gundealr_paletteram_w )
{
gundealr_state *state = space->machine().driver_data<gundealr_state>();
int r,g,b,val;
state->m_paletteram[offset] = data;
val = state->m_paletteram[offset & ~1];
r = (val >> 4) & 0x0f;
g = (val >> 0) & 0x0f;
val = state->m_paletteram[offset | 1];
b = (val >> 4) & 0x0f;
/* TODO: the bottom 4 bits are used as well, but I'm not sure about the meaning */
palette_set_color_rgb(space->machine(), offset / 2, pal4bit(r), pal4bit(g), pal4bit(b));
}
WRITE8_HANDLER( gundealr_fg_scroll_w )
{
gundealr_state *state = space->machine().driver_data<gundealr_state>();
state->m_scroll[offset] = data;
tilemap_set_scrollx(state->m_fg_tilemap, 0, state->m_scroll[1] | ((state->m_scroll[0] & 0x03) << 8));
tilemap_set_scrolly(state->m_fg_tilemap, 0, state->m_scroll[3] | ((state->m_scroll[2] & 0x03) << 8));
}
WRITE8_HANDLER( yamyam_fg_scroll_w )
{
gundealr_state *state = space->machine().driver_data<gundealr_state>();
state->m_scroll[offset] = data;
tilemap_set_scrollx(state->m_fg_tilemap, 0, state->m_scroll[0] | ((state->m_scroll[1] & 0x03) << 8));
tilemap_set_scrolly(state->m_fg_tilemap, 0, state->m_scroll[2] | ((state->m_scroll[3] & 0x03) << 8));
}
WRITE8_HANDLER( gundealr_flipscreen_w )
{
gundealr_state *state = space->machine().driver_data<gundealr_state>();
state->m_flipscreen = data;
tilemap_set_flip_all(space->machine(), state->m_flipscreen ? (TILEMAP_FLIPY | TILEMAP_FLIPX) : 0);
}
/***************************************************************************
Display refresh
***************************************************************************/
SCREEN_UPDATE( gundealr )
{
gundealr_state *state = screen->machine().driver_data<gundealr_state>();
tilemap_draw(bitmap, cliprect, state->m_bg_tilemap, 0, 0);
tilemap_draw(bitmap, cliprect, state->m_fg_tilemap, 0, 0);
return 0;
}