1 // license:BSD-3-Clause
2 // copyright-holders:Manuel Abadia
3 #include "emu.h"
4 #include "includes/xorworld.h"
5
6
7 /***************************************************************************
8
9 Convert the color PROMs into a more useable format.
10
11 Xor World has three 256x4 palette PROMs (one per gun).
12 The palette PROMs are connected to the RGB output this way:
13
14 bit 3 -- 220 ohm resistor -- RED/GREEN/BLUE
15 -- 460 ohm resistor -- RED/GREEN/BLUE
16 -- 1 kohm resistor -- RED/GREEN/BLUE
17 bit 0 -- 2.2kohm resistor -- RED/GREEN/BLUE
18
19 ***************************************************************************/
20
xorworld_palette(palette_device & palette) const21 void xorworld_state::xorworld_palette(palette_device &palette) const
22 {
23 const uint8_t *color_prom = memregion("proms")->base();
24
25 for (int i = 0; i < palette.entries(); i++)
26 {
27 int bit0, bit1, bit2, bit3;
28
29 // red component
30 bit0 = BIT(color_prom[0], 0);
31 bit1 = BIT(color_prom[0], 1);
32 bit2 = BIT(color_prom[0], 2);
33 bit3 = BIT(color_prom[0], 3);
34 int const r = 0x0e*bit0 + 0x1e*bit1 + 0x44*bit2 + 0x8f*bit3;
35 // green component
36 bit0 = BIT(color_prom[palette.entries()], 0);
37 bit1 = BIT(color_prom[palette.entries()], 1);
38 bit2 = BIT(color_prom[palette.entries()], 2);
39 bit3 = BIT(color_prom[palette.entries()], 3);
40 int const g = 0x0e*bit0 + 0x1e*bit1 + 0x44*bit2 + 0x8f*bit3;
41 // blue component
42 bit0 = BIT(color_prom[2 * palette.entries()], 0);
43 bit1 = BIT(color_prom[2 * palette.entries()], 1);
44 bit2 = BIT(color_prom[2 * palette.entries()], 2);
45 bit3 = BIT(color_prom[2 * palette.entries()], 3);
46 int const b = 0x0e*bit0 + 0x1e * bit1 + 0x44*bit2 + 0x8f*bit3;
47 palette.set_pen_color(i, rgb_t(r, g, b));
48
49 color_prom++;
50 }
51 }
52
videoram_w(offs_t offset,uint16_t data,uint16_t mem_mask)53 void xorworld_state::videoram_w(offs_t offset, uint16_t data, uint16_t mem_mask)
54 {
55 COMBINE_DATA(&m_videoram[offset]);
56 m_bg_tilemap->mark_tile_dirty(offset);
57 }
58
59 /*
60 Tile format
61 -----------
62
63 Word | Bit(s) | Description
64 -----+-FEDCBA98-76543210-+--------------------------
65 0 | ----xxxx xxxxxxxx | code
66 0 | xxxx---- -------- | color
67 */
68
TILE_GET_INFO_MEMBER(xorworld_state::get_bg_tile_info)69 TILE_GET_INFO_MEMBER(xorworld_state::get_bg_tile_info)
70 {
71 int data = m_videoram[tile_index];
72 int code = data & 0x0fff;
73
74 tileinfo.set(0, code, data >> 12, 0);
75 }
76
video_start()77 void xorworld_state::video_start()
78 {
79 m_bg_tilemap = &machine().tilemap().create(
80 *m_gfxdecode, tilemap_get_info_delegate(*this, FUNC(xorworld_state::get_bg_tile_info)), TILEMAP_SCAN_ROWS,
81 8, 8, 32, 32);
82 }
83
84 /*
85 Sprite Format
86 -------------
87
88 Word | Bit(s) | Description
89 -----+-FEDCBA98-76543210-+--------------------------
90 0 | -------- xxxxxxxx | x position
91 0 | xxxxxxxx -------- | y position
92 1 | -------- ------xx | flipxy? (not used)
93 1 | ----xxxx xxxxxx-- | sprite number
94 1 | xxxx---- -------- | sprite color
95 */
96
draw_sprites(bitmap_ind16 & bitmap,const rectangle & cliprect)97 void xorworld_state::draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect )
98 {
99 for (int i = 0; i < 0x40; i += 2)
100 {
101 int sx = m_spriteram[i] & 0x00ff;
102 int sy = 240 - (((m_spriteram[i] & 0xff00) >> 8) & 0xff);
103 int code = (m_spriteram[i+1] & 0x0ffc) >> 2;
104 int color = (m_spriteram[i+1] & 0xf000) >> 12;
105
106 m_gfxdecode->gfx(1)->transpen(bitmap,cliprect, code, color, 0, 0, sx, sy, 0);
107 }
108 }
109
screen_update(screen_device & screen,bitmap_ind16 & bitmap,const rectangle & cliprect)110 uint32_t xorworld_state::screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
111 {
112 m_bg_tilemap->draw(screen, bitmap, cliprect, 0, 0);
113 draw_sprites(bitmap, cliprect);
114 return 0;
115 }
116