/***************************************************************************
video.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "includes/citycon.h"
/***************************************************************************
Callbacks for the TileMap code
***************************************************************************/
static TILEMAP_MAPPER( citycon_scan )
{
/* logical (col,row) -> memory offset */
return (col & 0x1f) + ((row & 0x1f) << 5) + ((col & 0x60) << 5);
}
static TILE_GET_INFO( get_fg_tile_info )
{
citycon_state *state = machine.driver_data<citycon_state>();
SET_TILE_INFO(
0,
state->m_videoram[tile_index],
(tile_index & 0x03e0) >> 5, /* color depends on scanline only */
0);
}
static TILE_GET_INFO( get_bg_tile_info )
{
citycon_state *state = machine.driver_data<citycon_state>();
UINT8 *rom = machine.region("gfx4")->base();
int code = rom[0x1000 * state->m_bg_image + tile_index];
SET_TILE_INFO(
3 + state->m_bg_image,
code,
rom[0xc000 + 0x100 * state->m_bg_image + code],
0);
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
VIDEO_START( citycon )
{
citycon_state *state = machine.driver_data<citycon_state>();
state->m_fg_tilemap = tilemap_create(machine, get_fg_tile_info, citycon_scan, 8, 8, 128, 32);
state->m_bg_tilemap = tilemap_create(machine, get_bg_tile_info, citycon_scan, 8, 8, 128, 32);
tilemap_set_transparent_pen(state->m_fg_tilemap, 0);
tilemap_set_scroll_rows(state->m_fg_tilemap, 32);
}
/***************************************************************************
Memory handlers
***************************************************************************/
WRITE8_HANDLER( citycon_videoram_w )
{
citycon_state *state = space->machine().driver_data<citycon_state>();
state->m_videoram[offset] = data;
tilemap_mark_tile_dirty(state->m_fg_tilemap, offset);
}
WRITE8_HANDLER( citycon_linecolor_w )
{
citycon_state *state = space->machine().driver_data<citycon_state>();
state->m_linecolor[offset] = data;
}
WRITE8_HANDLER( citycon_background_w )
{
citycon_state *state = space->machine().driver_data<citycon_state>();
/* bits 4-7 control the background image */
if (state->m_bg_image != (data >> 4))
{
state->m_bg_image = (data >> 4);
tilemap_mark_all_tiles_dirty(state->m_bg_tilemap);
}
/* bit 0 flips screen */
/* it is also used to multiplex player 1 and player 2 controls */
flip_screen_set(space->machine(), data & 0x01);
/* bits 1-3 are unknown */
// if ((data & 0x0e) != 0) logerror("background register = %02x\n", data);
}
static void draw_sprites( running_machine &machine, bitmap_t *bitmap, const rectangle *cliprect )
{
citycon_state *state = machine.driver_data<citycon_state>();
int offs;
for (offs = state->m_spriteram_size - 4; offs >= 0; offs -= 4)
{
int sx, sy, flipx;
sx = state->m_spriteram[offs + 3];
sy = 239 - state->m_spriteram[offs];
flipx = ~state->m_spriteram[offs + 2] & 0x10;
if (flip_screen_get(machine))
{
sx = 240 - sx;
sy = 238 - sy;
flipx = !flipx;
}
drawgfx_transpen(bitmap, cliprect, machine.gfx[state->m_spriteram[offs + 1] & 0x80 ? 2 : 1],
state->m_spriteram[offs + 1] & 0x7f,
state->m_spriteram[offs + 2] & 0x0f,
flipx,flip_screen_get(machine),
sx, sy, 0);
}
}
INLINE void changecolor_RRRRGGGGBBBBxxxx( running_machine &machine, int color, int indx )
{
int data = machine.generic.paletteram.u8[2 * indx | 1] | (machine.generic.paletteram.u8[2 * indx] << 8);
palette_set_color_rgb(machine, color, pal4bit(data >> 12), pal4bit(data >> 8), pal4bit(data >> 4));
}
SCREEN_UPDATE( citycon )
{
citycon_state *state = screen->machine().driver_data<citycon_state>();
int offs, scroll;
/* Update the virtual palette to support text color code changing on every scanline. */
for (offs = 0; offs < 256; offs++)
{
int indx = state->m_linecolor[offs];
int i;
for (i = 0; i < 4; i++)
changecolor_RRRRGGGGBBBBxxxx(screen->machine(), 640 + 4 * offs + i, 512 + 4 * indx + i);
}
scroll = state->m_scroll[0] * 256 + state->m_scroll[1];
tilemap_set_scrollx(state->m_bg_tilemap, 0, scroll >> 1);
for (offs = 6; offs < 32; offs++)
tilemap_set_scrollx(state->m_fg_tilemap, offs, scroll);
tilemap_draw(bitmap, cliprect, state->m_bg_tilemap, 0, 0);
tilemap_draw(bitmap, cliprect, state->m_fg_tilemap, 0, 0);
draw_sprites(screen->machine(), bitmap, cliprect);
return 0;
}