15eb0001 |
1 | \r |
4abeeb4b |
2 | // This file is part of the PicoDrive Megadrive Emulator\r |
3 | \r |
4 | // This code is licensed under the GNU General Public License version 2.0 and the MAME License.\r |
5 | // You can choose the license that has the most advantages for you.\r |
6 | \r |
7 | // SVN repository can be found at http://code.google.com/p/cyclone68000/\r |
8 | \r |
15eb0001 |
9 | #include "PicoInt.h"\r |
10 | #ifndef __GNUC__\r |
11 | #pragma warning (disable:4706) // Disable assignment with conditional\r |
12 | #endif\r |
13 | \r |
14 | int (*PicoScan)(unsigned int num,unsigned short *data)=NULL;\r |
15 | \r |
16 | // Line colour indices - in the format 00ppcccc pp=palette, cccc=colour\r |
17 | static unsigned short HighCol[32+320+8]; // Gap for 32 column, and messy border on right\r |
18 | static int Scanline=0; // Scanline\r |
19 | \r |
20 | int PicoMask=0xfff; // Mask of which layers to draw\r |
21 | \r |
22 | static int TileNorm(unsigned short *pd,int addr,unsigned int *pal)\r |
23 | {\r |
24 | unsigned int pack=0; unsigned int t=0;\r |
25 | \r |
26 | pack=*(unsigned int *)(Pico.vram+addr); // Get 8 pixels\r |
27 | if (pack)\r |
28 | {\r |
29 | t=pack&0x0000f000; if (t) { t=pal[t>>12]; pd[0]=(unsigned short)t; }\r |
30 | t=pack&0x00000f00; if (t) { t=pal[t>> 8]; pd[1]=(unsigned short)t; }\r |
31 | t=pack&0x000000f0; if (t) { t=pal[t>> 4]; pd[2]=(unsigned short)t; }\r |
32 | t=pack&0x0000000f; if (t) { t=pal[t ]; pd[3]=(unsigned short)t; }\r |
33 | t=pack&0xf0000000; if (t) { t=pal[t>>28]; pd[4]=(unsigned short)t; }\r |
34 | t=pack&0x0f000000; if (t) { t=pal[t>>24]; pd[5]=(unsigned short)t; }\r |
35 | t=pack&0x00f00000; if (t) { t=pal[t>>20]; pd[6]=(unsigned short)t; }\r |
36 | t=pack&0x000f0000; if (t) { t=pal[t>>16]; pd[7]=(unsigned short)t; }\r |
37 | return 0;\r |
38 | }\r |
39 | \r |
40 | return 1; // Tile blank\r |
41 | }\r |
42 | \r |
43 | static int TileFlip(unsigned short *pd,int addr,unsigned int *pal)\r |
44 | {\r |
45 | unsigned int pack=0; unsigned int t=0;\r |
46 | \r |
47 | pack=*(unsigned int *)(Pico.vram+addr); // Get 8 pixels\r |
48 | if (pack)\r |
49 | {\r |
50 | t=pack&0x000f0000; if (t) { t=pal[t>>16]; pd[0]=(unsigned short)t; }\r |
51 | t=pack&0x00f00000; if (t) { t=pal[t>>20]; pd[1]=(unsigned short)t; }\r |
52 | t=pack&0x0f000000; if (t) { t=pal[t>>24]; pd[2]=(unsigned short)t; }\r |
53 | t=pack&0xf0000000; if (t) { t=pal[t>>28]; pd[3]=(unsigned short)t; }\r |
54 | t=pack&0x0000000f; if (t) { t=pal[t ]; pd[4]=(unsigned short)t; }\r |
55 | t=pack&0x000000f0; if (t) { t=pal[t>> 4]; pd[5]=(unsigned short)t; }\r |
56 | t=pack&0x00000f00; if (t) { t=pal[t>> 8]; pd[6]=(unsigned short)t; }\r |
57 | t=pack&0x0000f000; if (t) { t=pal[t>>12]; pd[7]=(unsigned short)t; }\r |
58 | return 0;\r |
59 | }\r |
60 | return 1; // Tile blank\r |
61 | }\r |
62 | \r |
63 | struct TileStrip\r |
64 | {\r |
65 | int nametab; // Position in VRAM of name table (for this tile line)\r |
66 | int line; // Line number in pixels 0x000-0x3ff within the virtual tilemap \r |
67 | int hscroll; // Horizontal scroll value in pixels for the line\r |
68 | int xmask; // X-Mask (0x1f - 0x7f) for horizontal wraparound in the tilemap\r |
69 | int high; // High or low tiles\r |
70 | };\r |
71 | \r |
72 | static int WrongPri=0; // 1 if there were tiles which are the wrong priority\r |
73 | \r |
74 | static int DrawStrip(struct TileStrip ts)\r |
75 | {\r |
76 | int tilex=0,dx=0,ty=0;\r |
77 | int blank=-1; // The tile we know is blank\r |
78 | \r |
79 | WrongPri=0;\r |
80 | \r |
81 | // Draw tiles across screen:\r |
82 | tilex=(-ts.hscroll)>>3;\r |
83 | ty=(ts.line&7)<<1; // Y-Offset into tile\r |
84 | for (dx=((ts.hscroll-1)&7)+1; dx<328; dx+=8,tilex++)\r |
85 | {\r |
86 | int code=0,addr=0,zero=0;\r |
87 | unsigned int *pal=NULL;\r |
88 | \r |
89 | code=Pico.vram[ts.nametab+(tilex&ts.xmask)];\r |
90 | if (code==blank) continue;\r |
91 | if ((code>>15)!=ts.high) { WrongPri=1; continue; }\r |
92 | \r |
93 | // Get tile address/2:\r |
94 | addr=(code&0x7ff)<<4;\r |
95 | if (code&0x1000) addr+=14-ty; else addr+=ty; // Y-flip\r |
96 | \r |
97 | pal=Pico.highpal+((code>>9)&0x30);\r |
98 | \r |
99 | if (code&0x0800) zero=TileFlip(HighCol+24+dx,addr,pal);\r |
100 | else zero=TileNorm(HighCol+24+dx,addr,pal);\r |
101 | \r |
102 | if (zero) blank=code; // We know this tile is blank now\r |
103 | }\r |
104 | \r |
105 | return 0;\r |
106 | }\r |
107 | \r |
108 | static int DrawLayer(int plane,int high)\r |
109 | {\r |
110 | struct PicoVideo *pvid=&Pico.video;\r |
111 | static char shift[4]={5,6,6,7}; // 32,64 or 128 sized tilemaps\r |
112 | struct TileStrip ts;\r |
113 | \r |
114 | // Work out the TileStrip to draw\r |
115 | \r |
116 | // Get vertical scroll value:\r |
117 | int vscroll=Pico.vsram[plane];\r |
118 | \r |
119 | int htab=pvid->reg[13]<<9; // Horizontal scroll table address\r |
120 | if ( pvid->reg[11]&2) htab+=Scanline<<1; // Offset by line\r |
121 | if ((pvid->reg[11]&1)==0) htab&=~0xf; // Offset by tile\r |
122 | htab+=plane; // A or B\r |
123 | \r |
124 | // Get horizontal scroll value\r |
125 | ts.hscroll=Pico.vram[htab&0x7fff];\r |
126 | \r |
127 | // Work out the name table size: 32 64 or 128 tiles (0-3)\r |
128 | int width=pvid->reg[16];\r |
129 | int height=(width>>4)&3; width&=3;\r |
130 | \r |
131 | ts.xmask=(1<<shift[width ])-1; // X Mask in tiles\r |
132 | int ymask=(8<<shift[height])-1; // Y Mask in pixels\r |
133 | \r |
134 | // Find name table:\r |
135 | if (plane==0) ts.nametab=(pvid->reg[2]&0x38)<< 9; // A\r |
136 | else ts.nametab=(pvid->reg[4]&0x07)<<12; // B\r |
137 | \r |
138 | // Find the line in the name table\r |
139 | ts.line=(vscroll+Scanline)&ymask;\r |
140 | ts.nametab+=(ts.line>>3)<<shift[width];\r |
141 | \r |
142 | ts.high=high;\r |
143 | \r |
144 | DrawStrip(ts);\r |
145 | return 0;\r |
146 | }\r |
147 | \r |
148 | static int DrawWindow(int high)\r |
149 | {\r |
150 | struct PicoVideo *pvid=&Pico.video;\r |
151 | struct TileStrip ts;\r |
152 | \r |
153 | ts.line=Scanline;\r |
154 | ts.hscroll=0;\r |
155 | \r |
156 | // Find name table line:\r |
157 | if (Pico.video.reg[12]&1)\r |
158 | {\r |
159 | ts.nametab=(pvid->reg[3]&0x3c)<<9; // 40-cell mode\r |
160 | ts.nametab+=(ts.line>>3)<<6;\r |
161 | }\r |
162 | else\r |
163 | {\r |
164 | ts.nametab=(pvid->reg[3]&0x3e)<<9; // 32-cell mode\r |
165 | ts.nametab+=(ts.line>>3)<<5;\r |
166 | }\r |
167 | \r |
168 | ts.xmask=0x3f;\r |
169 | ts.high=high;\r |
170 | \r |
171 | DrawStrip(ts);\r |
172 | return 0;\r |
173 | }\r |
174 | \r |
175 | static int DrawSprite(int sy,unsigned short *sprite,int high)\r |
176 | {\r |
177 | int sx=0,width=0,height=0;\r |
178 | int row=0,code=0;\r |
179 | unsigned int *pal=NULL;\r |
180 | int tile=0,delta=0;\r |
181 | int i=0;\r |
182 | \r |
183 | code=sprite[2];\r |
184 | if ((code>>15)!=high) { WrongPri=1; return 0; } // Wrong priority\r |
185 | \r |
186 | height=sprite[1]>>8;\r |
187 | width=(height>>2)&3; height&=3;\r |
188 | width++; height++; // Width and height in tiles\r |
189 | if (Scanline>=sy+(height<<3)) return 0; // Not on this line after all\r |
190 | \r |
191 | row=Scanline-sy; // Row of the sprite we are on\r |
192 | pal=Pico.highpal+((code>>9)&0x30); // Get palette pointer\r |
193 | if (code&0x1000) row=(height<<3)-1-row; // Flip Y\r |
194 | \r |
195 | tile=code&0x7ff; // Tile number\r |
196 | tile+=row>>3; // Tile number increases going down\r |
197 | delta=height; // Delta to increase tile by going right\r |
198 | if (code&0x0800) { tile+=delta*(width-1); delta=-delta; } // Flip X\r |
199 | \r |
200 | tile<<=4; tile+=(row&7)<<1; // Tile address\r |
201 | delta<<=4; // Delta of address\r |
202 | \r |
203 | sx=(sprite[3]&0x1ff)-0x78; // Get X coordinate + 8\r |
204 | \r |
205 | for (i=0; i<width; i++,sx+=8,tile+=delta)\r |
206 | {\r |
207 | if (sx<=0 || sx>=328) continue; // Offscreen\r |
208 | \r |
209 | tile&=0x7fff; // Clip tile address\r |
210 | if (code&0x0800) TileFlip(HighCol+24+sx,tile,pal);\r |
211 | else TileNorm(HighCol+24+sx,tile,pal);\r |
212 | }\r |
213 | \r |
214 | return 0;\r |
215 | }\r |
216 | \r |
217 | static int DrawAllSprites(int high)\r |
218 | {\r |
219 | struct PicoVideo *pvid=&Pico.video;\r |
220 | int table=0;\r |
221 | int i=0,link=0;\r |
222 | unsigned char spin[80]; // Sprite index\r |
223 | \r |
224 | WrongPri=0;\r |
225 | \r |
226 | table=pvid->reg[5]&0x7f;\r |
227 | if (pvid->reg[12]&1) table&=0x7e; // Lowest bit 0 in 40-cell mode\r |
228 | table<<=8; // Get sprite table address/2\r |
229 | \r |
230 | for (;;)\r |
231 | {\r |
232 | unsigned short *sprite=NULL;\r |
233 | \r |
234 | spin[i]=(unsigned char)link;\r |
235 | sprite=Pico.vram+((table+(link<<2))&0x7ffc); // Find sprite\r |
236 | \r |
237 | // Find next sprite\r |
238 | link=sprite[1]&0x7f;\r |
239 | if (link==0 || i>=79) break; // End of sprites\r |
240 | i++;\r |
241 | }\r |
242 | \r |
243 | // Go through sprites backwards:\r |
244 | for ( ;i>=0; i--)\r |
245 | {\r |
246 | unsigned short *sprite=NULL;\r |
247 | int sy=0;\r |
248 | \r |
249 | sprite=Pico.vram+((table+(spin[i]<<2))&0x7ffc); // Find sprite\r |
250 | \r |
251 | sy=(sprite[0]&0x1ff)-0x80; // Get Y coordinate\r |
252 | \r |
253 | if (Scanline>=sy && Scanline<sy+32) DrawSprite(sy,sprite,high); // Possibly on this line\r |
254 | }\r |
255 | \r |
256 | return 0;\r |
257 | }\r |
258 | \r |
259 | static void BackFill()\r |
260 | {\r |
261 | unsigned int back=0;\r |
262 | unsigned int *pd=NULL,*end=NULL;\r |
263 | \r |
264 | // Start with a blank scanline (background colour):\r |
265 | back=Pico.video.reg[7]&0x3f;\r |
266 | back=Pico.highpal[back];\r |
267 | back|=back<<16;\r |
268 | \r |
269 | pd= (unsigned int *)(HighCol+32);\r |
270 | end=(unsigned int *)(HighCol+32+320);\r |
271 | \r |
272 | do { pd[0]=pd[1]=pd[2]=pd[3]=back; pd+=4; } while (pd<end);\r |
273 | }\r |
274 | \r |
275 | static int DrawDisplay()\r |
276 | {\r |
277 | int win=0,edge=0,full=0;\r |
278 | int bhigh=1,ahigh=1,shigh=1;\r |
279 | \r |
280 | // Find out if the window is on this line:\r |
281 | win=Pico.video.reg[0x12];\r |
282 | edge=(win&0x1f)<<3;\r |
283 | \r |
284 | if (win&0x80) { if (Scanline>=edge) full=1; }\r |
285 | else { if (Scanline< edge) full=1; }\r |
286 | \r |
287 | if (PicoMask&0x04) { DrawLayer(1,0); bhigh=WrongPri; }\r |
288 | if (PicoMask&0x08) { if (full) DrawWindow(0); else DrawLayer(0,0); ahigh=WrongPri; }\r |
289 | if (PicoMask&0x10) { DrawAllSprites(0); shigh=WrongPri; }\r |
290 | \r |
291 | if (bhigh) if (PicoMask&0x20) DrawLayer(1,1);\r |
292 | if (ahigh) if (PicoMask&0x40) { if (full) DrawWindow(1); else DrawLayer(0,1); }\r |
293 | if (shigh) if (PicoMask&0x80) DrawAllSprites(1);\r |
294 | return 0;\r |
295 | }\r |
296 | \r |
297 | static int UpdatePalette()\r |
298 | {\r |
299 | int c=0;\r |
300 | \r |
301 | // Update palette:\r |
302 | for (c=0;c<64;c++) Pico.highpal[c]=(unsigned short)PicoCram(Pico.cram[c]);\r |
303 | Pico.m.dirtyPal=0;\r |
304 | \r |
305 | return 0;\r |
306 | }\r |
307 | \r |
308 | static int Overlay()\r |
309 | {\r |
310 | int col=0,x=0;\r |
311 | \r |
312 | if (PmovAction==0) return 0;\r |
313 | if (Scanline>=4) return 0;\r |
314 | \r |
315 | if (PmovAction&1) col =0x00f;\r |
316 | if (PmovAction&2) col|=0x0f0;\r |
317 | col=PicoCram(col);\r |
318 | \r |
319 | for (x=0;x<4;x++) HighCol[32+x]=(unsigned short)col;\r |
320 | \r |
321 | return 0;\r |
322 | }\r |
323 | \r |
324 | static int Skip=0;\r |
325 | \r |
326 | \r |
327 | int PicoLine(int scan)\r |
328 | {\r |
329 | if (Skip>0) { Skip--; return 0; } // Skip rendering lines\r |
330 | \r |
331 | Scanline=scan;\r |
332 | \r |
333 | if (Pico.m.dirtyPal) UpdatePalette();\r |
334 | \r |
335 | // Draw screen:\r |
336 | if (PicoMask&0x02) BackFill();\r |
337 | if (Pico.video.reg[1]&0x40) DrawDisplay();\r |
338 | \r |
339 | Overlay();\r |
340 | \r |
341 | if (Pico.video.reg[12]&1)\r |
342 | {\r |
343 | Skip=PicoScan(Scanline,HighCol+32); // 40-column mode\r |
344 | }\r |
345 | else\r |
346 | {\r |
347 | // Crop, centre and return 32-column mode\r |
348 | memset(HighCol, 0,64); // Left border\r |
349 | memset(HighCol+288,0,64); // Right border\r |
350 | Skip=PicoScan(Scanline,HighCol);\r |
351 | }\r |
352 | \r |
353 | return 0;\r |
354 | }\r |
355 | \r |