/***************************************************************************
video.c
Traverse USA
L Taylor
J Clegg
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "includes/travrusa.h"
/***************************************************************************
Convert the color PROMs into a more useable format.
Traverse USA has one 256x8 character palette PROM (some versions have two
256x4), one 32x8 sprite palette PROM, and one 256x4 sprite color lookup
table PROM.
I don't know for sure how the palette PROMs are connected to the RGB
output, but it's probably something like this; note that RED and BLUE
are swapped wrt the usual configuration.
bit 7 -- 220 ohm resistor -- RED
-- 470 ohm resistor -- RED
-- 220 ohm resistor -- GREEN
-- 470 ohm resistor -- GREEN
-- 1 kohm resistor -- GREEN
-- 220 ohm resistor -- BLUE
-- 470 ohm resistor -- BLUE
bit 0 -- 1 kohm resistor -- BLUE
***************************************************************************/
PALETTE_INIT( travrusa )
{
int i;
/* allocate the colortable */
machine.colortable = colortable_alloc(machine, 0x90);
/* create a lookup table for the palette */
for (i = 0; i < 0x80; i++)
{
int bit0, bit1, bit2;
int r, g, b;
/* red component */
bit0 = 0;
bit1 = (color_prom[i] >> 6) & 0x01;
bit2 = (color_prom[i] >> 7) & 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] >> 0) & 0x01;
bit1 = (color_prom[i] >> 1) & 0x01;
bit2 = (color_prom[i] >> 2) & 0x01;
b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
colortable_palette_set_color(machine.colortable, i, MAKE_RGB(r, g, b));
}
for (i = 0x80; i < 0x90; i++)
{
int bit0, bit1, bit2;
int r, g, b;
/* red component */
bit0 = 0;
bit1 = (color_prom[(i - 0x80) + 0x200] >> 6) & 0x01;
bit2 = (color_prom[(i - 0x80) + 0x200] >> 7) & 0x01;
r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (color_prom[(i - 0x80) + 0x200] >> 3) & 0x01;
bit1 = (color_prom[(i - 0x80) + 0x200] >> 4) & 0x01;
bit2 = (color_prom[(i - 0x80) + 0x200] >> 5) & 0x01;
g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = (color_prom[(i - 0x80) + 0x200] >> 0) & 0x01;
bit1 = (color_prom[(i - 0x80) + 0x200] >> 1) & 0x01;
bit2 = (color_prom[(i - 0x80) + 0x200] >> 2) & 0x01;
b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
colortable_palette_set_color(machine.colortable, i, MAKE_RGB(r, g, b));
}
/* color_prom now points to the beginning of the lookup table */
color_prom += 0x220;
/* characters */
for (i = 0; i < 0x80; i++)
colortable_entry_set_value(machine.colortable, i, i);
/* sprites */
for (i = 0x80; i < 0x100; i++)
{
UINT8 ctabentry = (color_prom[i - 0x80] & 0x0f) | 0x80;
colortable_entry_set_value(machine.colortable, i, ctabentry);
}
}
PALETTE_INIT( shtrider )
{
int i;
/* allocate the colortable */
machine.colortable = colortable_alloc(machine, 0x90);
/* create a lookup table for the palette */
for (i = 0; i < 0x80; i++)
{
int bit0, bit1, bit2;
int r, g, b;
/* red component */
bit0 = 0;
bit1 = (color_prom[i + 0x000] >> 2) & 0x01;
bit2 = (color_prom[i + 0x000] >> 3) & 0x01;
r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (color_prom[i + 0x100] >> 3) & 0x01;
bit1 = (color_prom[i + 0x000] >> 0) & 0x01;
bit2 = (color_prom[i + 0x000] >> 1) & 0x01;
g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = (color_prom[i + 0x100] >> 0) & 0x01;
bit1 = (color_prom[i + 0x100] >> 1) & 0x01;
bit2 = (color_prom[i + 0x100] >> 2) & 0x01;
b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
colortable_palette_set_color(machine.colortable, i, MAKE_RGB(r, g, b));
}
for (i = 0x80; i < 0x90; i++)
{
int bit0, bit1, bit2;
int r, g, b;
/* red component */
bit0 = 0;
bit1 = (color_prom[(i - 0x80) + 0x200] >> 6) & 0x01;
bit2 = (color_prom[(i - 0x80) + 0x200] >> 7) & 0x01;
r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (color_prom[(i - 0x80) + 0x200] >> 3) & 0x01;
bit1 = (color_prom[(i - 0x80) + 0x200] >> 4) & 0x01;
bit2 = (color_prom[(i - 0x80) + 0x200] >> 5) & 0x01;
g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = (color_prom[(i - 0x80) + 0x200] >> 0) & 0x01;
bit1 = (color_prom[(i - 0x80) + 0x200] >> 1) & 0x01;
bit2 = (color_prom[(i - 0x80) + 0x200] >> 2) & 0x01;
b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
colortable_palette_set_color(machine.colortable, i, MAKE_RGB(r, g, b));
}
/* color_prom now points to the beginning of the lookup table */
color_prom += 0x220;
/* characters */
for (i = 0; i < 0x80; i++)
colortable_entry_set_value(machine.colortable, i, i);
/* sprites */
for (i = 0x80; i < 0x100; i++)
{
UINT8 ctabentry = (color_prom[i - 0x80] & 0x0f) | 0x80;
colortable_entry_set_value(machine.colortable, i, ctabentry);
}
}
/***************************************************************************
Callbacks for the TileMap code
***************************************************************************/
static TILE_GET_INFO( get_tile_info )
{
travrusa_state *state = machine.driver_data<travrusa_state>();
UINT8 attr = state->m_videoram[2 * tile_index + 1];
int flags = TILE_FLIPXY((attr & 0x30) >> 4);
tileinfo->group = ((attr & 0x0f) == 0x0f) ? 1 : 0; /* tunnels */
SET_TILE_INFO(
0,
state->m_videoram[2 * tile_index] + ((attr & 0xc0) << 2),
attr & 0x0f,
flags);
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
VIDEO_START( travrusa )
{
travrusa_state *state = machine.driver_data<travrusa_state>();
state->save_item(NAME(state->m_scrollx));
state->m_bg_tilemap = tilemap_create(machine, get_tile_info, tilemap_scan_rows, 8, 8, 64, 32);
tilemap_set_transmask(state->m_bg_tilemap, 0, 0xff, 0x00); /* split type 0 is totally transparent in front half */
tilemap_set_transmask(state->m_bg_tilemap, 1, 0x3f, 0xc0); /* split type 1 has pens 6 and 7 opaque - tunnels */
tilemap_set_scroll_rows(state->m_bg_tilemap, 4);
}
/***************************************************************************
Memory handlers
***************************************************************************/
WRITE8_HANDLER( travrusa_videoram_w )
{
travrusa_state *state = space->machine().driver_data<travrusa_state>();
state->m_videoram[offset] = data;
tilemap_mark_tile_dirty(state->m_bg_tilemap, offset / 2);
}
static void set_scroll( running_machine &machine )
{
travrusa_state *state = machine.driver_data<travrusa_state>();
int i;
for (i = 0; i <= 2; i++)
tilemap_set_scrollx(state->m_bg_tilemap, i, state->m_scrollx[0] + 256 * state->m_scrollx[1]);
tilemap_set_scrollx(state->m_bg_tilemap, 3, 0);
}
WRITE8_HANDLER( travrusa_scroll_x_low_w )
{
travrusa_state *state = space->machine().driver_data<travrusa_state>();
state->m_scrollx[0] = data;
set_scroll(space->machine());
}
WRITE8_HANDLER( travrusa_scroll_x_high_w )
{
travrusa_state *state = space->machine().driver_data<travrusa_state>();
state->m_scrollx[1] = data;
set_scroll(space->machine());
}
WRITE8_HANDLER( travrusa_flipscreen_w )
{
/* screen flip is handled both by software and hardware */
data ^= ~input_port_read(space->machine(), "DSW2") & 1;
flip_screen_set(space->machine(), data & 1);
coin_counter_w(space->machine(), 0, data & 0x02);
coin_counter_w(space->machine(), 1, data & 0x20);
}
/***************************************************************************
Display refresh
***************************************************************************/
static void draw_sprites(running_machine &machine, bitmap_t *bitmap,const rectangle *cliprect)
{
travrusa_state *state = machine.driver_data<travrusa_state>();
int offs;
static const rectangle spritevisiblearea =
{
1*8, 31*8-1,
0*8, 24*8-1
};
static const rectangle spritevisibleareaflip =
{
1*8, 31*8-1,
8*8, 32*8-1
};
rectangle clip = *cliprect;
if (flip_screen_get(machine))
sect_rect(&clip, &spritevisibleareaflip);
else
sect_rect(&clip, &spritevisiblearea);
for (offs = state->m_spriteram_size - 4; offs >= 0; offs -= 4)
{
int sx = ((state->m_spriteram[offs + 3] + 8) & 0xff) - 8;
int sy = 240 - state->m_spriteram[offs];
int code = state->m_spriteram[offs + 2];
int attr = state->m_spriteram[offs + 1];
int flipx = attr & 0x40;
int flipy = attr & 0x80;
if (flip_screen_get(machine))
{
sx = 240 - sx;
sy = 240 - sy;
flipx = !flipx;
flipy = !flipy;
}
drawgfx_transpen(bitmap, &clip, machine.gfx[1],
code,
attr & 0x0f,
flipx, flipy,
sx, sy, 0);
}
}
SCREEN_UPDATE( travrusa )
{
travrusa_state *state = screen->machine().driver_data<travrusa_state>();
tilemap_draw(bitmap, cliprect, state->m_bg_tilemap, TILEMAP_DRAW_LAYER1, 0);
draw_sprites(screen->machine(), bitmap,cliprect);
tilemap_draw(bitmap, cliprect, state->m_bg_tilemap, TILEMAP_DRAW_LAYER0, 0);
return 0;
}