// license:BSD-3-Clause
// copyright-holders:Nicola Salmoria
/***************************************************************************
video.c
Functions to emulate the video hardware of the machine.
***************************************************************************/
#include "emu.h"
#include "includes/crbaloon.h"
/***************************************************************************
Convert the color PROMs into a more useable format.
Crazy Balloon has no PROMs, the color code directly maps to a color:
all bits are inverted
bit 3 HALF (intensity)
bit 2 BLUE
bit 1 GREEN
bit 0 RED
***************************************************************************/
PALETTE_INIT_MEMBER(crbaloon_state, crbaloon)
{
int i;
for (i = 0; i < palette.entries(); i++)
{
uint8_t pen;
int h, r, g, b;
if (i & 0x01)
pen = i >> 1;
else
pen = 0x0f;
h = (~pen & 0x08) ? 0xff : 0x55;
r = h * ((~pen >> 0) & 1);
g = h * ((~pen >> 1) & 1);
b = h * ((~pen >> 2) & 1);
palette.set_pen_color(i, rgb_t(r, g, b));
}
}
WRITE8_MEMBER(crbaloon_state::crbaloon_videoram_w)
{
m_videoram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset);
}
WRITE8_MEMBER(crbaloon_state::crbaloon_colorram_w)
{
m_colorram[offset] = data;
m_bg_tilemap->mark_tile_dirty(offset);
}
TILE_GET_INFO_MEMBER(crbaloon_state::get_bg_tile_info)
{
int code = m_videoram[tile_index];
int color = m_colorram[tile_index] & 0x0f;
SET_TILE_INFO_MEMBER(0, code, color, 0);
}
void crbaloon_state::video_start()
{
m_bg_tilemap = &machine().tilemap().create(*m_gfxdecode, tilemap_get_info_delegate(FUNC(crbaloon_state::get_bg_tile_info),this), TILEMAP_SCAN_ROWS_FLIP_XY, 8, 8, 32, 32);
save_item(NAME(m_collision_address));
save_item(NAME(m_collision_address_clear));
}
uint16_t crbaloon_state::crbaloon_get_collision_address()
{
return m_collision_address_clear ? 0xffff : m_collision_address;
}
void crbaloon_state::crbaloon_set_clear_collision_address(int _crbaloon_collision_address_clear)
{
m_collision_address_clear = !_crbaloon_collision_address_clear; /* active LO */
}
void crbaloon_state::draw_sprite_and_check_collision(bitmap_ind16 &bitmap)
{
int y;
uint8_t code = m_spriteram[0] & 0x0f;
uint8_t color = m_spriteram[0] >> 4;
uint8_t sy = m_spriteram[2] - 32;
uint8_t *gfx = memregion("gfx2")->base() + (code << 7);
if (flip_screen())
sy += 32;
/* assume no collision */
m_collision_address = 0xffff;
for (y = 0x1f; y >= 0; y--)
{
int x;
uint8_t data = 0;
uint8_t sx = m_spriteram[1];
for (x = 0x1f; x >= 0; x--)
{
int bit;
if ((x & 0x07) == 0x07)
/* get next byte to draw, but no drawing in VBLANK */
data = (sy >= 0xe0) ? 0 : gfx[((x >> 3) << 5) | y];
bit = data & 0x80;
/* draw the current pixel, but check collision first */
if (bit)
{
if (bitmap.pix16(sy, sx) & 0x01)
/* compute the collision address -- the +1 is via observation
of the game code, probably wrong for cocktail mode */
m_collision_address = ((((sy ^ 0xff) >> 3) << 5) | ((sx ^ 0xff) >> 3)) + 1;
bitmap.pix16(sy, sx) = (color << 1) | 1;
}
sx = sx + 1;
data = data << 1;
}
sy = sy + 1;
}
}
uint32_t crbaloon_state::screen_update_crbaloon(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
draw_sprite_and_check_collision(bitmap);
return 0;
}