// license:BSD-3-Clause
// copyright-holders:Brad Oliver
/***************************************************************************
tankbatt.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "includes/tankbatt.h"
/***************************************************************************
Convert the color PROMs into a more useable format.
***************************************************************************/
PALETTE_INIT_MEMBER(tankbatt_state, tankbatt)
{
const uint8_t *color_prom = memregion("proms")->base();
int i;
#define RES_1 0xc0 /* this is a guess */
#define RES_2 0x3f /* this is a guess */
/* create a lookup table for the palette */
for (i = 0; i < 0x100; i++)
{
int bit0, bit1, bit2, bit3;
int r, g, b;
bit0 = (color_prom[i] >> 0) & 0x01; /* intensity */
bit1 = (color_prom[i] >> 1) & 0x01; /* red */
bit2 = (color_prom[i] >> 2) & 0x01; /* green */
bit3 = (color_prom[i] >> 3) & 0x01; /* blue */
/* red component */
r = RES_1 * bit1;
if (bit1) r += RES_2 * bit0;
/* green component */
g = RES_1 * bit2;
if (bit2) g += RES_2 * bit0;
/* blue component */
b = RES_1 * bit3;
if (bit3) b += RES_2 * bit0;
palette.set_indirect_color(i, rgb_t(r, g, b));
}
for (i = 0; i < 0x200; i += 2)
{
palette.set_pen_indirect(i + 0, 0);
palette.set_pen_indirect(i + 1, i >> 1);
}
}
WRITE8_MEMBER(tankbatt_state::videoram_w)
{
m_videoram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset);
}
TILE_GET_INFO_MEMBER(tankbatt_state::get_bg_tile_info)
{
int code = m_videoram[tile_index];
int color = m_videoram[tile_index] | 0x01;
SET_TILE_INFO_MEMBER(0, code, color, 0);
}
void tankbatt_state::video_start()
{
m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(FUNC(tankbatt_state::get_bg_tile_info),this), TILEMAP_SCAN_ROWS, 8, 8, 32, 32);
}
void tankbatt_state::draw_bullets(bitmap_ind16 &bitmap, const rectangle &cliprect)
{
for (int offs = 0;offs < m_bulletsram.bytes();offs += 2)
{
int color = 0xff; /* cyan, same color as the tanks */
int x = m_bulletsram[offs + 1];
int y = 255 - m_bulletsram[offs] - 2;
m_gfxdecode->gfx(1)->opaque(bitmap,cliprect,
0, /* this is just a square, generated by the hardware */
color,
0,0,
x,y);
}
}
uint32_t tankbatt_state::screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
draw_bullets(bitmap, cliprect);
return 0;
}