/***************************************************************************
video.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "driver.h"
UINT8 *bankp_videoram2;
UINT8 *bankp_colorram2;
static int scroll_x;
static int priority;
static tilemap *bg_tilemap, *fg_tilemap;
static colortable *bankp_colortable;
/***************************************************************************
Convert the color PROMs into a more useable format.
Bank Panic has a 32x8 palette PROM (I'm not sure whether the second 16
bytes are used - they contain the same colors as the first 16 with only
one different) and two 256x4 lookup table PROMs (one for charset #1, one
for charset #2 - only the first 128 nibbles seem to be used).
I don't know for sure how the palette PROM is connected to the RGB output,
but it's probably the usual:
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( bankp )
{
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])
/* allocate the colortable */
bankp_colortable = colortable_alloc(machine, 32);
for (i = 0;i < 32;i++)
{
int bit0,bit1,bit2,r,g,b;
/* red component */
bit0 = (*color_prom >> 0) & 0x01;
bit1 = (*color_prom >> 1) & 0x01;
bit2 = (*color_prom >> 2) & 0x01;
r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* green component */
bit0 = (*color_prom >> 3) & 0x01;
bit1 = (*color_prom >> 4) & 0x01;
bit2 = (*color_prom >> 5) & 0x01;
g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
/* blue component */
bit0 = 0;
bit1 = (*color_prom >> 6) & 0x01;
bit2 = (*color_prom >> 7) & 0x01;
b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
colortable_palette_set_color(bankp_colortable,i,MAKE_RGB(r,g,b));
color_prom++;
}
/* color_prom now points to the beginning of the lookup table */
/* charset #1 lookup table */
for (i = 0;i < machine->gfx[0]->total_colors * machine->gfx[0]->color_granularity;i++)
colortable_entry_set_value(bankp_colortable, machine->gfx[0]->color_base + i, *color_prom++ & 0x0f);
color_prom += 128; /* skip the bottom half of the PROM - seems to be not used */
/* charset #2 lookup table */
for (i = 0;i < machine->gfx[1]->total_colors * machine->gfx[1]->color_granularity;i++)
colortable_entry_set_value(bankp_colortable, machine->gfx[1]->color_base + i, *color_prom++ & 0x0f);
/* the bottom half of the PROM seems to be not used */
}
WRITE8_HANDLER( bankp_scroll_w )
{
scroll_x = data;
}
WRITE8_HANDLER( bankp_videoram_w )
{
videoram[offset] = data;
tilemap_mark_tile_dirty(fg_tilemap, offset);
}
WRITE8_HANDLER( bankp_colorram_w )
{
colorram[offset] = data;
tilemap_mark_tile_dirty(fg_tilemap, offset);
}
WRITE8_HANDLER( bankp_videoram2_w )
{
bankp_videoram2[offset] = data;
tilemap_mark_tile_dirty(bg_tilemap, offset);
}
WRITE8_HANDLER( bankp_colorram2_w )
{
bankp_colorram2[offset] = data;
tilemap_mark_tile_dirty(bg_tilemap, offset);
}
WRITE8_HANDLER( bankp_out_w )
{
/* bits 0-1 are playfield priority */
/* TODO: understand how this works */
priority = data & 0x03;
/* bits 2-3 unknown (2 is used) */
/* bit 4 controls NMI */
interrupt_enable_w(0,(data & 0x10)>>4);
/* bit 5 controls screen flip */
flip_screen_set(data & 0x20);
/* bits 6-7 unknown */
}
static TILE_GET_INFO( get_bg_tile_info )
{
int code = bankp_videoram2[tile_index] + 256 * (bankp_colorram2[tile_index] & 0x07);
int color = bankp_colorram2[tile_index] >> 4;
int flags = (bankp_colorram2[tile_index] & 0x08) ? TILE_FLIPX : 0;
SET_TILE_INFO(1, code, color, flags);
tileinfo->group = color;
}
static TILE_GET_INFO( get_fg_tile_info )
{
int code = videoram[tile_index] + 256 * ((colorram[tile_index] & 3) >> 0);
int color = colorram[tile_index] >> 3;
int flags = (colorram[tile_index] & 0x04) ? TILE_FLIPX : 0;
SET_TILE_INFO(0, code, color, flags);
tileinfo->group = color;
}
VIDEO_START( bankp )
{
bg_tilemap = tilemap_create(get_bg_tile_info, tilemap_scan_rows,
TILEMAP_TYPE_PEN, 8, 8, 32, 32);
fg_tilemap = tilemap_create(get_fg_tile_info, tilemap_scan_rows,
TILEMAP_TYPE_PEN, 8, 8, 32, 32);
colortable_configure_tilemap_groups(bankp_colortable, bg_tilemap, machine->gfx[1], 0);
colortable_configure_tilemap_groups(bankp_colortable, fg_tilemap, machine->gfx[0], 0);
}
VIDEO_UPDATE( bankp )
{
if (flip_screen)
{
tilemap_set_scrollx(fg_tilemap, 0, -scroll_x);
tilemap_set_scrollx(bg_tilemap, 0, 0);
}
else
{
tilemap_set_scrollx(fg_tilemap, 0, scroll_x);
tilemap_set_scrollx(bg_tilemap, 0, 0);
}
// only one bit matters?
switch (priority)
{
case 0: // combat hawk uses this
tilemap_draw(bitmap, cliprect, bg_tilemap, TILEMAP_DRAW_OPAQUE, 0);
tilemap_draw(bitmap, cliprect, fg_tilemap, 0, 0);
break;
case 1:
tilemap_draw(bitmap, cliprect, bg_tilemap, TILEMAP_DRAW_OPAQUE, 0);
tilemap_draw(bitmap, cliprect, fg_tilemap, 0, 0);
break;
case 2:
tilemap_draw(bitmap, cliprect, fg_tilemap, TILEMAP_DRAW_OPAQUE, 0);
tilemap_draw(bitmap, cliprect, bg_tilemap, 0, 0);
break;
case 3:
tilemap_draw(bitmap, cliprect, fg_tilemap, TILEMAP_DRAW_OPAQUE, 0); // just a guess
tilemap_draw(bitmap, cliprect, bg_tilemap, 0, 0);
break;
}
return 0;
}