/***************************************************************************
video.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "includes/seicross.h"
/***************************************************************************
Convert the color PROMs into a more useable format.
Seicross has two 32x8 palette PROMs, connected to the RGB output this way:
bit 7 -- 220 ohm resistor -- BLUE
-- 470 ohm resistor -- BLUE
-- 220 ohm resistor -- GREEN
-- 470 ohm resistor -- GREEN
-- 1 kohm resistor -- GREEN
-- 220 ohm resistor -- RED
-- 470 ohm resistor -- RED
bit 0 -- 1 kohm resistor -- RED
***************************************************************************/
PALETTE_INIT( seicross )
{
int i;
for (i = 0;i < machine.total_colors();i++)
{
int bit0,bit1,bit2,r,g,b;
/* red component */
bit0 = (color_prom[i] >> 0) & 0x01;
bit1 = (color_prom[i] >> 1) & 0x01;
bit2 = (color_prom[i] >> 2) & 0x01;
r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (color_prom[i] >> 3) & 0x01;
bit1 = (color_prom[i] >> 4) & 0x01;
bit2 = (color_prom[i] >> 5) & 0x01;
g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = (color_prom[i] >> 6) & 0x01;
bit1 = (color_prom[i] >> 7) & 0x01;
b = 0x4f * bit0 + 0xa8 * bit1;
palette_set_color(machine,i,MAKE_RGB(r,g,b));
}
}
WRITE8_HANDLER( seicross_videoram_w )
{
seicross_state *state = space->machine().driver_data<seicross_state>();
state->m_videoram[offset] = data;
tilemap_mark_tile_dirty(state->m_bg_tilemap, offset);
}
WRITE8_HANDLER( seicross_colorram_w )
{
/* bit 5 of the address is not used for color memory. There is just */
/* 512k of memory; every two consecutive rows share the same memory */
/* region. */
seicross_state *state = space->machine().driver_data<seicross_state>();
offset &= 0xffdf;
state->m_colorram[offset] = data;
state->m_colorram[offset + 0x20] = data;
tilemap_mark_tile_dirty(state->m_bg_tilemap, offset);
tilemap_mark_tile_dirty(state->m_bg_tilemap, offset + 0x20);
}
static TILE_GET_INFO( get_bg_tile_info )
{
seicross_state *state = machine.driver_data<seicross_state>();
int code = state->m_videoram[tile_index] + ((state->m_colorram[tile_index] & 0x10) << 4);
int color = state->m_colorram[tile_index] & 0x0f;
int flags = ((state->m_colorram[tile_index] & 0x40) ? TILE_FLIPX : 0) | ((state->m_colorram[tile_index] & 0x80) ? TILE_FLIPY : 0);
SET_TILE_INFO(0, code, color, flags);
}
VIDEO_START( seicross )
{
seicross_state *state = machine.driver_data<seicross_state>();
state->m_bg_tilemap = tilemap_create(machine, get_bg_tile_info, tilemap_scan_rows,
8, 8, 32, 32);
tilemap_set_scroll_cols(state->m_bg_tilemap, 32);
}
static void draw_sprites(running_machine &machine, bitmap_t *bitmap, const rectangle *cliprect )
{
seicross_state *state = machine.driver_data<seicross_state>();
UINT8 *spriteram = state->m_spriteram;
UINT8 *spriteram_2 = state->m_spriteram2;
int offs;
for (offs = state->m_spriteram_size - 4; offs >= 0; offs -= 4)
{
int x = spriteram[offs + 3];
drawgfx_transpen(bitmap,cliprect,machine.gfx[1],
(spriteram[offs] & 0x3f) + ((spriteram[offs + 1] & 0x10) << 2) + 128,
spriteram[offs + 1] & 0x0f,
spriteram[offs] & 0x40,spriteram[offs] & 0x80,
x,240-spriteram[offs + 2],0);
if(x>0xf0)
drawgfx_transpen(bitmap,cliprect,machine.gfx[1],
(spriteram[offs] & 0x3f) + ((spriteram[offs + 1] & 0x10) << 2) + 128,
spriteram[offs + 1] & 0x0f,
spriteram[offs] & 0x40,spriteram[offs] & 0x80,
x-256,240-spriteram[offs + 2],0);
}
for (offs = state->m_spriteram2_size - 4; offs >= 0; offs -= 4)
{
int x = spriteram_2[offs + 3];
drawgfx_transpen(bitmap,cliprect,machine.gfx[1],
(spriteram_2[offs] & 0x3f) + ((spriteram_2[offs + 1] & 0x10) << 2),
spriteram_2[offs + 1] & 0x0f,
spriteram_2[offs] & 0x40,spriteram_2[offs] & 0x80,
x,240-spriteram_2[offs + 2],0);
if(x>0xf0)
drawgfx_transpen(bitmap,cliprect,machine.gfx[1],
(spriteram_2[offs] & 0x3f) + ((spriteram_2[offs + 1] & 0x10) << 2),
spriteram_2[offs + 1] & 0x0f,
spriteram_2[offs] & 0x40,spriteram_2[offs] & 0x80,
x-256,240-spriteram_2[offs + 2],0);
}
}
SCREEN_UPDATE( seicross )
{
seicross_state *state = screen->machine().driver_data<seicross_state>();
int col;
for (col = 0; col < 32; col++)
tilemap_set_scrolly(state->m_bg_tilemap, col, state->m_row_scroll[col]);
tilemap_draw(bitmap, cliprect, state->m_bg_tilemap, 0, 0);
draw_sprites(screen->machine(), bitmap, cliprect);
return 0;
}