/***************************************************************************
video.c
Traverse USA
L Taylor
J Clegg
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
UINT8 *travrusa_videoram;
static tilemap *bg_tilemap;
/***************************************************************************
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;
#define TOTAL_COLORS(gfxn) (machine->gfx[gfxn]->total_colors * machine->gfx[gfxn]->color_granularity)
#define COLOR(gfxn,offs) (colortable[machine->drv->gfxdecodeinfo[gfxn].color_codes_start + offs])
/* character palette */
for (i = 0;i < 128;i++)
{
int bit0,bit1,bit2,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;
palette_set_color(machine,i,MAKE_RGB(r,g,b));
}
color_prom += 256;
/* sprite palette */
for (i = 0;i < 16;i++)
{
int bit0,bit1,bit2,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;
palette_set_color(machine,i+128,MAKE_RGB(r,g,b));
}
color_prom += 32;
/* color_prom now points to the beginning of the lookup table */
/* sprite lookup table */
for (i = 0;i < TOTAL_COLORS(1);i++)
COLOR(1,i) = (color_prom[i] & 0x0f) + 128;
}
PALETTE_INIT( shtrider )
{
int i;
#define TOTAL_COLORS(gfxn) (machine->gfx[gfxn]->total_colors * machine->gfx[gfxn]->color_granularity)
#define COLOR(gfxn,offs) (colortable[machine->drv->gfxdecodeinfo[gfxn].color_codes_start + offs])
/* character palette */
for (i = 0;i < 128;i++)
{
int bit0,bit1,bit2,r,g,b;
/* red component */
bit0 = 0;
bit1 = (color_prom[i] >> 2) & 0x01;
bit2 = (color_prom[i] >> 3) & 0x01;
r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (color_prom[i+256] >> 3) & 0x01;
bit1 = (color_prom[i] >> 0) & 0x01;
bit2 = (color_prom[i] >> 1) & 0x01;
g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = (color_prom[i+256] >> 0) & 0x01;
bit1 = (color_prom[i+256] >> 1) & 0x01;
bit2 = (color_prom[i+256] >> 2) & 0x01;
b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
palette_set_color(machine,i,MAKE_RGB(r,g,b));
}
color_prom += 512;
/* color_prom now points to the beginning of the sprite palette */
/* sprite palette */
for (i = 0;i < 16;i++)
{
int bit0,bit1,bit2,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;
palette_set_color(machine,i+128,MAKE_RGB(r,g,b));
}
color_prom += 32;
/* color_prom now points to the beginning of the sprite lookup table */
/* sprite lookup table */
for (i = 0;i < TOTAL_COLORS(1);i++)
COLOR(1,i) = (color_prom[i] & 0x0f) + 128;
}
/***************************************************************************
Callbacks for the TileMap code
***************************************************************************/
static TILE_GET_INFO( get_tile_info )
{
UINT8 attr = travrusa_videoram[2*tile_index+1];
int flags = TILE_FLIPXY((attr & 0x30) >> 4);
tileinfo->group = ((attr & 0x0f) == 0x0f) ? 1 : 0; /* tunnels */
SET_TILE_INFO(
0,
travrusa_videoram[2*tile_index] + ((attr & 0xc0) << 2),
attr & 0x0f,
flags);
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
VIDEO_START( travrusa )
{
bg_tilemap = tilemap_create(get_tile_info,tilemap_scan_rows,TILEMAP_TYPE_PEN,8,8,64,32);
tilemap_set_transmask(bg_tilemap,0,0xff,0x00); /* split type 0 is totally transparent in front half */
tilemap_set_transmask(bg_tilemap,1,0x3f,0xc0); /* split type 1 has pens 6 and 7 opaque - tunnels */
tilemap_set_scroll_rows(bg_tilemap,4);
}
/***************************************************************************
Memory handlers
***************************************************************************/
WRITE8_HANDLER( travrusa_videoram_w )
{
travrusa_videoram[offset] = data;
tilemap_mark_tile_dirty(bg_tilemap,offset/2);
}
static int scrollx[2];
static void set_scroll(void)
{
int i;
for (i = 0;i <= 2;i++)
tilemap_set_scrollx(bg_tilemap,i,scrollx[0] + 256 * scrollx[1]);
tilemap_set_scrollx(bg_tilemap,3,0);
}
WRITE8_HANDLER( travrusa_scroll_x_low_w )
{
scrollx[0] = data;
set_scroll();
}
WRITE8_HANDLER( travrusa_scroll_x_high_w )
{
scrollx[1] = data;
set_scroll();
}
WRITE8_HANDLER( travrusa_flipscreen_w )
{
/* screen flip is handled both by software and hardware */
data ^= ~readinputport(4) & 1;
flip_screen_set(data & 1);
coin_counter_w(0,data & 0x02);
coin_counter_w(1,data & 0x20);
}
/***************************************************************************
Display refresh
***************************************************************************/
static void draw_sprites(running_machine *machine, mame_bitmap *bitmap,const rectangle *cliprect)
{
int offs;
static rectangle spritevisiblearea =
{
1*8, 31*8-1,
0*8, 24*8-1
};
static rectangle spritevisibleareaflip =
{
1*8, 31*8-1,
8*8, 32*8-1
};
rectangle clip = *cliprect;
if (flip_screen)
sect_rect(&clip, &spritevisibleareaflip);
else
sect_rect(&clip, &spritevisiblearea);
for (offs = spriteram_size - 4;offs >= 0;offs -= 4)
{
int sx = ((spriteram[offs + 3] + 8) & 0xff) - 8;
int sy = 240 - spriteram[offs];
int code = spriteram[offs + 2];
int attr = spriteram[offs + 1];
int flipx = attr & 0x40;
int flipy = attr & 0x80;
if (flip_screen)
{
sx = 240 - sx;
sy = 240 - sy;
flipx = !flipx;
flipy = !flipy;
}
drawgfx(bitmap,machine->gfx[1],
code,
attr & 0x0f,
flipx,flipy,
sx,sy,
&clip,TRANSPARENCY_PEN,0);
}
}
VIDEO_UPDATE( travrusa )
{
tilemap_draw(bitmap,cliprect,bg_tilemap,TILEMAP_DRAW_LAYER1,0);
draw_sprites(machine, bitmap,cliprect);
tilemap_draw(bitmap,cliprect,bg_tilemap,TILEMAP_DRAW_LAYER0,0);
return 0;
}