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// license:BSD-3-Clause
// copyright-holders:Manuel Abadia
#include "emu.h"
#include "includes/xorworld.h"
/***************************************************************************
Convert the color PROMs into a more useable format.
Xor World has three 256x4 palette PROMs (one per gun).
The palette PROMs are connected to the RGB output this way:
bit 3 -- 220 ohm resistor -- RED/GREEN/BLUE
-- 460 ohm resistor -- RED/GREEN/BLUE
-- 1 kohm resistor -- RED/GREEN/BLUE
bit 0 -- 2.2kohm resistor -- RED/GREEN/BLUE
***************************************************************************/
void xorworld_state::xorworld_palette(palette_device &palette) const
{
const uint8_t *color_prom = memregion("proms")->base();
for (int i = 0; i < palette.entries(); i++)
{
int bit0, bit1, bit2, bit3;
// red component
bit0 = BIT(color_prom[0], 0);
bit1 = BIT(color_prom[0], 1);
bit2 = BIT(color_prom[0], 2);
bit3 = BIT(color_prom[0], 3);
int const r = 0x0e*bit0 + 0x1e*bit1 + 0x44*bit2 + 0x8f*bit3;
// green component
bit0 = BIT(color_prom[palette.entries()], 0);
bit1 = BIT(color_prom[palette.entries()], 1);
bit2 = BIT(color_prom[palette.entries()], 2);
bit3 = BIT(color_prom[palette.entries()], 3);
int const g = 0x0e*bit0 + 0x1e*bit1 + 0x44*bit2 + 0x8f*bit3;
// blue component
bit0 = BIT(color_prom[2 * palette.entries()], 0);
bit1 = BIT(color_prom[2 * palette.entries()], 1);
bit2 = BIT(color_prom[2 * palette.entries()], 2);
bit3 = BIT(color_prom[2 * palette.entries()], 3);
int const b = 0x0e*bit0 + 0x1e * bit1 + 0x44*bit2 + 0x8f*bit3;
palette.set_pen_color(i, rgb_t(r, g, b));
color_prom++;
}
}
void xorworld_state::videoram_w(offs_t offset, uint16_t data, uint16_t mem_mask)
{
COMBINE_DATA(&m_videoram[offset]);
m_bg_tilemap->mark_tile_dirty(offset);
}
/*
Tile format
-----------
Word | Bit(s) | Description
-----+-FEDCBA98-76543210-+--------------------------
0 | ----xxxx xxxxxxxx | code
0 | xxxx---- -------- | color
*/
TILE_GET_INFO_MEMBER(xorworld_state::get_bg_tile_info)
{
int data = m_videoram[tile_index];
int code = data & 0x0fff;
tileinfo.set(0, code, data >> 12, 0);
}
void xorworld_state::video_start()
{
m_bg_tilemap = &machine().tilemap().create(
*m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(xorworld_state::get_bg_tile_info)), TILEMAP_SCAN_ROWS,
8, 8, 32, 32);
}
/*
Sprite Format
-------------
Word | Bit(s) | Description
-----+-FEDCBA98-76543210-+--------------------------
0 | -------- xxxxxxxx | x position
0 | xxxxxxxx -------- | y position
1 | -------- ------xx | flipxy? (not used)
1 | ----xxxx xxxxxx-- | sprite number
1 | xxxx---- -------- | sprite color
*/
void xorworld_state::draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect )
{
for (int i = 0; i < 0x40; i += 2)
{
int sx = m_spriteram[i] & 0x00ff;
int sy = 240 - (((m_spriteram[i] & 0xff00) >> 8) & 0xff);
int code = (m_spriteram[i+1] & 0x0ffc) >> 2;
int color = (m_spriteram[i+1] & 0xf000) >> 12;
m_gfxdecode->gfx(1)->transpen(bitmap,cliprect, code, color, 0, 0, sx, sy, 0);
}
}
uint32_t xorworld_state::screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
draw_sprites(bitmap, cliprect);
return 0;
}
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