// license:BSD-3-Clause
// copyright-holders:Pierpaolo Prazzoli
/***************************************************************************
video.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "includes/gng.h"
/***************************************************************************
Callbacks for the TileMap code
***************************************************************************/
TILE_GET_INFO_MEMBER(gng_state::get_fg_tile_info)
{
uint8_t attr = m_fgvideoram[tile_index + 0x400];
SET_TILE_INFO_MEMBER(0,
m_fgvideoram[tile_index] + ((attr & 0xc0) << 2),
attr & 0x0f,
TILE_FLIPYX((attr & 0x30) >> 4));
}
TILE_GET_INFO_MEMBER(gng_state::get_bg_tile_info)
{
uint8_t attr = m_bgvideoram[tile_index + 0x400];
SET_TILE_INFO_MEMBER(1,
m_bgvideoram[tile_index] + ((attr & 0xc0) << 2),
attr & 0x07,
TILE_FLIPYX((attr & 0x30) >> 4));
tileinfo.group = (attr & 0x08) >> 3;
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
void gng_state::video_start()
{
m_fg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(gng_state::get_fg_tile_info)), TILEMAP_SCAN_ROWS, 8, 8, 32, 32);
m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(gng_state::get_bg_tile_info)), TILEMAP_SCAN_COLS, 16, 16, 32, 32);
m_fg_tilemap->set_transparent_pen(3);
m_bg_tilemap->set_transmask(0, 0xff, 0x00); // split type 0 is totally transparent in front half
m_bg_tilemap->set_transmask(1, 0x41, 0xbe); // split type 1 has pens 0 and 6 transparent in front half
}
/***************************************************************************
Memory handlers
***************************************************************************/
WRITE8_MEMBER(gng_state::gng_fgvideoram_w)
{
m_fgvideoram[offset] = data;
m_fg_tilemap->mark_tile_dirty(offset & 0x3ff);
}
WRITE8_MEMBER(gng_state::gng_bgvideoram_w)
{
m_bgvideoram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset & 0x3ff);
}
WRITE8_MEMBER(gng_state::gng_bgscrollx_w)
{
m_scrollx[offset] = data;
m_bg_tilemap->set_scrollx(0, m_scrollx[0] + 256 * m_scrollx[1]);
}
WRITE8_MEMBER(gng_state::gng_bgscrolly_w)
{
m_scrolly[offset] = data;
m_bg_tilemap->set_scrolly(0, m_scrolly[0] + 256 * m_scrolly[1]);
}
WRITE_LINE_MEMBER(gng_state::flipscreen_w)
{
flip_screen_set(!state);
}
/***************************************************************************
Display refresh
***************************************************************************/
void gng_state::draw_sprites( bitmap_ind16 &bitmap, const rectangle &cliprect )
{
uint8_t *buffered_spriteram = m_spriteram->buffer();
gfx_element *gfx = m_gfxdecode->gfx(2);
int offs;
for (offs = m_spriteram->bytes() - 4; offs >= 0; offs -= 4)
{
uint8_t attributes = buffered_spriteram[offs + 1];
int sx = buffered_spriteram[offs + 3] - 0x100 * (attributes & 0x01);
int sy = buffered_spriteram[offs + 2];
int flipx = attributes & 0x04;
int flipy = attributes & 0x08;
if (flip_screen())
{
sx = 240 - sx;
sy = 240 - sy;
flipx = !flipx;
flipy = !flipy;
}
gfx->transpen(bitmap,cliprect,
buffered_spriteram[offs] + ((attributes << 2) & 0x300),
(attributes >> 4) & 3,
flipx,flipy,
sx,sy,15);
}
}
uint32_t gng_state::screen_update_gng(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
m_bg_tilemap->draw(screen, bitmap, cliprect, TILEMAP_DRAW_LAYER1, 0);
draw_sprites(bitmap, cliprect);
m_bg_tilemap->draw(screen, bitmap, cliprect, TILEMAP_DRAW_LAYER0, 0);
m_fg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
return 0;
}