1 /***************************************************************************
2
3 vidhrdw.c
4
5 Functions to emulate the video hardware of the machine.
6
7 ***************************************************************************/
8
9 #include "driver.h"
10 #include "vidhrdw/generic.h"
11
12
13
14 unsigned char *gunsmoke_bg_scrolly;
15 unsigned char *gunsmoke_bg_scrollx;
16 static int chon,objon,bgon;
17 static int sprite3bank;
18 static int flipscreen;
19
20 static struct osd_bitmap * bgbitmap;
21 static unsigned char bgmap[9][9][2];
22
23
24 /***************************************************************************
25
26 Convert the color PROMs into a more useable format.
27
28 Gunsmoke has three 256x4 palette PROMs (one per gun) and a lot ;-) of
29 256x4 lookup table PROMs.
30 The palette PROMs are connected to the RGB output this way:
31
32 bit 3 -- 220 ohm resistor -- RED/GREEN/BLUE
33 -- 470 ohm resistor -- RED/GREEN/BLUE
34 -- 1 kohm resistor -- RED/GREEN/BLUE
35 bit 0 -- 2.2kohm resistor -- RED/GREEN/BLUE
36
37 ***************************************************************************/
gunsmoke_vh_convert_color_prom(unsigned char * palette,unsigned short * colortable,const unsigned char * color_prom)38 void gunsmoke_vh_convert_color_prom(unsigned char *palette, unsigned short *colortable,const unsigned char *color_prom)
39 {
40 int i;
41 #define TOTAL_COLORS(gfxn) (Machine->gfx[gfxn]->total_colors * Machine->gfx[gfxn]->color_granularity)
42 #define COLOR(gfxn,offs) (colortable[Machine->drv->gfxdecodeinfo[gfxn].color_codes_start + offs])
43
44
45 for (i = 0;i < Machine->drv->total_colors;i++)
46 {
47 int bit0,bit1,bit2,bit3;
48
49
50 bit0 = (color_prom[0] >> 0) & 0x01;
51 bit1 = (color_prom[0] >> 1) & 0x01;
52 bit2 = (color_prom[0] >> 2) & 0x01;
53 bit3 = (color_prom[0] >> 3) & 0x01;
54 *(palette++) = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
55 bit0 = (color_prom[Machine->drv->total_colors] >> 0) & 0x01;
56 bit1 = (color_prom[Machine->drv->total_colors] >> 1) & 0x01;
57 bit2 = (color_prom[Machine->drv->total_colors] >> 2) & 0x01;
58 bit3 = (color_prom[Machine->drv->total_colors] >> 3) & 0x01;
59 *(palette++) = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
60 bit0 = (color_prom[2*Machine->drv->total_colors] >> 0) & 0x01;
61 bit1 = (color_prom[2*Machine->drv->total_colors] >> 1) & 0x01;
62 bit2 = (color_prom[2*Machine->drv->total_colors] >> 2) & 0x01;
63 bit3 = (color_prom[2*Machine->drv->total_colors] >> 3) & 0x01;
64 *(palette++) = 0x0e * bit0 + 0x1f * bit1 + 0x43 * bit2 + 0x8f * bit3;
65
66 color_prom++;
67 }
68
69 color_prom += 2*Machine->drv->total_colors;
70 /* color_prom now points to the beginning of the lookup table */
71
72 /* characters use colors 64-79 */
73 for (i = 0;i < TOTAL_COLORS(0);i++)
74 COLOR(0,i) = *(color_prom++) + 64;
75 color_prom += 128; /* skip the bottom half of the PROM - not used */
76
77 /* background tiles use colors 0-63 */
78 for (i = 0;i < TOTAL_COLORS(1);i++)
79 {
80 COLOR(1,i) = color_prom[0] + 16 * (color_prom[256] & 0x03);
81 color_prom++;
82 }
83 color_prom += TOTAL_COLORS(1);
84
85 /* sprites use colors 128-255 */
86 for (i = 0;i < TOTAL_COLORS(2);i++)
87 {
88 COLOR(2,i) = color_prom[0] + 16 * (color_prom[256] & 0x07) + 128;
89 color_prom++;
90 }
91 color_prom += TOTAL_COLORS(2);
92 }
93
94
95
gunsmoke_vh_start(void)96 int gunsmoke_vh_start(void)
97 {
98 if ((bgbitmap = bitmap_alloc(9*32,9*32)) == 0)
99 return 1;
100
101 if (generic_vh_start() == 1)
102 {
103 bitmap_free(bgbitmap);
104 return 1;
105 }
106
107 memset (bgmap, 0xff, sizeof (bgmap));
108
109 return 0;
110 }
111
112
gunsmoke_vh_stop(void)113 void gunsmoke_vh_stop(void)
114 {
115 bitmap_free(bgbitmap);
116 }
117
118
119
WRITE_HANDLER(gunsmoke_c804_w)120 WRITE_HANDLER( gunsmoke_c804_w )
121 {
122 int bankaddress;
123 unsigned char *RAM = memory_region(REGION_CPU1);
124
125
126 /* bits 0 and 1 are for coin counters? - we ignore them */
127
128 /* bits 2 and 3 select the ROM bank */
129 bankaddress = 0x10000 + (data & 0x0c) * 0x1000;
130 cpu_setbank(1,&RAM[bankaddress]);
131
132 /* bit 5 resets the sound CPU? - we ignore it */
133
134 /* bit 6 flips screen */
135 if (flipscreen != (data & 0x40))
136 {
137 flipscreen = data & 0x40;
138 // memset(dirtybuffer,1,c1942_backgroundram_size);
139 }
140
141 /* bit 7 enables characters? */
142 chon = data & 0x80;
143 }
144
145
146
WRITE_HANDLER(gunsmoke_d806_w)147 WRITE_HANDLER( gunsmoke_d806_w )
148 {
149 /* bits 0-2 select the sprite 3 bank */
150 sprite3bank = data & 0x07;
151
152 /* bit 4 enables bg 1? */
153 bgon = data & 0x10;
154
155 /* bit 5 enables sprites? */
156 objon = data & 0x20;
157 }
158
159
160
161 /***************************************************************************
162
163 Draw the game screen in the given osd_bitmap.
164 Do NOT call osd_update_display() from this function, it will be called by
165 the main emulation engine.
166
167 ***************************************************************************/
gunsmoke_vh_screenrefresh(struct osd_bitmap * bitmap,int full_refresh)168 void gunsmoke_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh)
169 {
170 int offs,sx,sy;
171 int bg_scrolly, bg_scrollx;
172 unsigned char *p=memory_region(REGION_GFX4);
173 int top,left,xscroll,yscroll;
174
175
176 /* TODO: support flipscreen */
177 if (bgon)
178 {
179 bg_scrolly = gunsmoke_bg_scrolly[0] + 256 * gunsmoke_bg_scrolly[1];
180 bg_scrollx = gunsmoke_bg_scrollx[0];
181 offs = 16 * ((bg_scrolly>>5)+8)+2*(bg_scrollx>>5) ;
182 if (bg_scrollx & 0x80) offs -= 0x10;
183
184 top = 8 - (bg_scrolly>>5) % 9;
185 left = (bg_scrollx>>5) % 9;
186
187 bg_scrolly&=0x1f;
188 bg_scrollx&=0x1f;
189
190 for (sy = 0;sy <9;sy++)
191 {
192 int ty = (sy + top) % 9;
193 offs &= 0x7fff; /* Enforce limits (for top of scroll) */
194
195 for (sx = 0;sx < 9;sx++)
196 {
197 int tile, attr, offset;
198 int tx = (sx + left) % 9;
199 unsigned char *map = &bgmap[ty][tx][0];
200 offset=offs+(sx*2);
201
202 tile=p[offset];
203 attr=p[offset+1];
204
205 if (tile != map[0] || attr != map[1])
206 {
207 map[0] = tile;
208 map[1] = attr;
209 tile+=256*(attr&0x01);
210 drawgfx(bgbitmap,Machine->gfx[1],
211 tile,
212 (attr & 0x3c) >> 2,
213 attr & 0x40,attr & 0x80,
214 (8-ty)*32, tx*32,
215 0,
216 TRANSPARENCY_NONE,0);
217 }
218 map += 2;
219 }
220 offs-=0x10;
221 }
222
223 xscroll = (top*32-bg_scrolly);
224 yscroll = -(left*32+bg_scrollx);
225 copyscrollbitmap(bitmap,bgbitmap,
226 1,&xscroll,
227 1,&yscroll,
228 &Machine->visible_area,
229 TRANSPARENCY_NONE,0);
230 }
231 else fillbitmap(bitmap,Machine->pens[0],&Machine->visible_area);
232
233
234
235 if (objon)
236 {
237 /* Draw the sprites. */
238 for (offs = spriteram_size - 32;offs >= 0;offs -= 32)
239 {
240 int bank,flipx,flipy;
241
242
243 bank = (spriteram[offs + 1] & 0xc0) >> 6;
244 if (bank == 3) bank += sprite3bank;
245
246 sx = spriteram[offs + 3] - ((spriteram[offs + 1] & 0x20) << 3);
247 sy = spriteram[offs + 2];
248 flipx = 0;
249 flipy = spriteram[offs + 1] & 0x10;
250 if (flipscreen)
251 {
252 sx = 240 - sx;
253 sy = 240 - sy;
254 flipx = !flipx;
255 flipy = !flipy;
256 }
257
258 drawgfx(bitmap,Machine->gfx[2],
259 spriteram[offs] + 256 * bank,
260 spriteram[offs + 1] & 0x0f,
261 flipx,flipy,
262 sx,sy,
263 &Machine->visible_area,TRANSPARENCY_PEN,0);
264 }
265 }
266
267
268 if (chon)
269 {
270 /* draw the frontmost playfield. They are characters, but draw them as sprites */
271 for (offs = videoram_size - 1;offs >= 0;offs--)
272 {
273 sx = offs % 32;
274 sy = offs / 32;
275 if (flipscreen)
276 {
277 sx = 31 - sx;
278 sy = 31 - sy;
279 }
280
281 drawgfx(bitmap,Machine->gfx[0],
282 videoram[offs] + ((colorram[offs] & 0xc0) << 2),
283 colorram[offs] & 0x1f,
284 !flipscreen,!flipscreen,
285 8*sx,8*sy,
286 &Machine->visible_area,TRANSPARENCY_COLOR,79);
287 }
288 }
289 }
290