15eb0001 |
1 | \r |
4abeeb4b |
2 | // This file is part of the PicoDrive Megadrive Emulator\r |
3 | \r |
c41b9b97 |
4 | // Copyright (c) 2011 FinalDave (emudave (at) gmail.com)\r |
5 | \r |
4abeeb4b |
6 | // This code is licensed under the GNU General Public License version 2.0 and the MAME License.\r |
7 | // You can choose the license that has the most advantages for you.\r |
8 | \r |
9 | // SVN repository can be found at http://code.google.com/p/cyclone68000/\r |
10 | \r |
15eb0001 |
11 | #include "PicoInt.h"\r |
12 | #ifndef __GNUC__\r |
13 | #pragma warning (disable:4706) // Disable assignment with conditional\r |
14 | #endif\r |
15 | \r |
16 | int (*PicoScan)(unsigned int num,unsigned short *data)=NULL;\r |
17 | \r |
18 | // Line colour indices - in the format 00ppcccc pp=palette, cccc=colour\r |
19 | static unsigned short HighCol[32+320+8]; // Gap for 32 column, and messy border on right\r |
20 | static int Scanline=0; // Scanline\r |
21 | \r |
22 | int PicoMask=0xfff; // Mask of which layers to draw\r |
23 | \r |
24 | static int TileNorm(unsigned short *pd,int addr,unsigned int *pal)\r |
25 | {\r |
26 | unsigned int pack=0; unsigned int t=0;\r |
27 | \r |
28 | pack=*(unsigned int *)(Pico.vram+addr); // Get 8 pixels\r |
29 | if (pack)\r |
30 | {\r |
31 | t=pack&0x0000f000; if (t) { t=pal[t>>12]; pd[0]=(unsigned short)t; }\r |
32 | t=pack&0x00000f00; if (t) { t=pal[t>> 8]; pd[1]=(unsigned short)t; }\r |
33 | t=pack&0x000000f0; if (t) { t=pal[t>> 4]; pd[2]=(unsigned short)t; }\r |
34 | t=pack&0x0000000f; if (t) { t=pal[t ]; pd[3]=(unsigned short)t; }\r |
35 | t=pack&0xf0000000; if (t) { t=pal[t>>28]; pd[4]=(unsigned short)t; }\r |
36 | t=pack&0x0f000000; if (t) { t=pal[t>>24]; pd[5]=(unsigned short)t; }\r |
37 | t=pack&0x00f00000; if (t) { t=pal[t>>20]; pd[6]=(unsigned short)t; }\r |
38 | t=pack&0x000f0000; if (t) { t=pal[t>>16]; pd[7]=(unsigned short)t; }\r |
39 | return 0;\r |
40 | }\r |
41 | \r |
42 | return 1; // Tile blank\r |
43 | }\r |
44 | \r |
45 | static int TileFlip(unsigned short *pd,int addr,unsigned int *pal)\r |
46 | {\r |
47 | unsigned int pack=0; unsigned int t=0;\r |
48 | \r |
49 | pack=*(unsigned int *)(Pico.vram+addr); // Get 8 pixels\r |
50 | if (pack)\r |
51 | {\r |
52 | t=pack&0x000f0000; if (t) { t=pal[t>>16]; pd[0]=(unsigned short)t; }\r |
53 | t=pack&0x00f00000; if (t) { t=pal[t>>20]; pd[1]=(unsigned short)t; }\r |
54 | t=pack&0x0f000000; if (t) { t=pal[t>>24]; pd[2]=(unsigned short)t; }\r |
55 | t=pack&0xf0000000; if (t) { t=pal[t>>28]; pd[3]=(unsigned short)t; }\r |
56 | t=pack&0x0000000f; if (t) { t=pal[t ]; pd[4]=(unsigned short)t; }\r |
57 | t=pack&0x000000f0; if (t) { t=pal[t>> 4]; pd[5]=(unsigned short)t; }\r |
58 | t=pack&0x00000f00; if (t) { t=pal[t>> 8]; pd[6]=(unsigned short)t; }\r |
59 | t=pack&0x0000f000; if (t) { t=pal[t>>12]; pd[7]=(unsigned short)t; }\r |
60 | return 0;\r |
61 | }\r |
62 | return 1; // Tile blank\r |
63 | }\r |
64 | \r |
65 | struct TileStrip\r |
66 | {\r |
67 | int nametab; // Position in VRAM of name table (for this tile line)\r |
68 | int line; // Line number in pixels 0x000-0x3ff within the virtual tilemap \r |
69 | int hscroll; // Horizontal scroll value in pixels for the line\r |
70 | int xmask; // X-Mask (0x1f - 0x7f) for horizontal wraparound in the tilemap\r |
71 | int high; // High or low tiles\r |
72 | };\r |
73 | \r |
74 | static int WrongPri=0; // 1 if there were tiles which are the wrong priority\r |
75 | \r |
76 | static int DrawStrip(struct TileStrip ts)\r |
77 | {\r |
78 | int tilex=0,dx=0,ty=0;\r |
79 | int blank=-1; // The tile we know is blank\r |
80 | \r |
81 | WrongPri=0;\r |
82 | \r |
83 | // Draw tiles across screen:\r |
84 | tilex=(-ts.hscroll)>>3;\r |
85 | ty=(ts.line&7)<<1; // Y-Offset into tile\r |
86 | for (dx=((ts.hscroll-1)&7)+1; dx<328; dx+=8,tilex++)\r |
87 | {\r |
88 | int code=0,addr=0,zero=0;\r |
89 | unsigned int *pal=NULL;\r |
90 | \r |
91 | code=Pico.vram[ts.nametab+(tilex&ts.xmask)];\r |
92 | if (code==blank) continue;\r |
93 | if ((code>>15)!=ts.high) { WrongPri=1; continue; }\r |
94 | \r |
95 | // Get tile address/2:\r |
96 | addr=(code&0x7ff)<<4;\r |
97 | if (code&0x1000) addr+=14-ty; else addr+=ty; // Y-flip\r |
98 | \r |
99 | pal=Pico.highpal+((code>>9)&0x30);\r |
100 | \r |
101 | if (code&0x0800) zero=TileFlip(HighCol+24+dx,addr,pal);\r |
102 | else zero=TileNorm(HighCol+24+dx,addr,pal);\r |
103 | \r |
104 | if (zero) blank=code; // We know this tile is blank now\r |
105 | }\r |
106 | \r |
107 | return 0;\r |
108 | }\r |
109 | \r |
110 | static int DrawLayer(int plane,int high)\r |
111 | {\r |
112 | struct PicoVideo *pvid=&Pico.video;\r |
113 | static char shift[4]={5,6,6,7}; // 32,64 or 128 sized tilemaps\r |
114 | struct TileStrip ts;\r |
115 | \r |
116 | // Work out the TileStrip to draw\r |
117 | \r |
118 | // Get vertical scroll value:\r |
119 | int vscroll=Pico.vsram[plane];\r |
120 | \r |
121 | int htab=pvid->reg[13]<<9; // Horizontal scroll table address\r |
122 | if ( pvid->reg[11]&2) htab+=Scanline<<1; // Offset by line\r |
123 | if ((pvid->reg[11]&1)==0) htab&=~0xf; // Offset by tile\r |
124 | htab+=plane; // A or B\r |
125 | \r |
126 | // Get horizontal scroll value\r |
127 | ts.hscroll=Pico.vram[htab&0x7fff];\r |
128 | \r |
129 | // Work out the name table size: 32 64 or 128 tiles (0-3)\r |
130 | int width=pvid->reg[16];\r |
131 | int height=(width>>4)&3; width&=3;\r |
132 | \r |
133 | ts.xmask=(1<<shift[width ])-1; // X Mask in tiles\r |
134 | int ymask=(8<<shift[height])-1; // Y Mask in pixels\r |
135 | \r |
136 | // Find name table:\r |
137 | if (plane==0) ts.nametab=(pvid->reg[2]&0x38)<< 9; // A\r |
138 | else ts.nametab=(pvid->reg[4]&0x07)<<12; // B\r |
139 | \r |
140 | // Find the line in the name table\r |
141 | ts.line=(vscroll+Scanline)&ymask;\r |
142 | ts.nametab+=(ts.line>>3)<<shift[width];\r |
143 | \r |
144 | ts.high=high;\r |
145 | \r |
146 | DrawStrip(ts);\r |
147 | return 0;\r |
148 | }\r |
149 | \r |
150 | static int DrawWindow(int high)\r |
151 | {\r |
152 | struct PicoVideo *pvid=&Pico.video;\r |
153 | struct TileStrip ts;\r |
154 | \r |
155 | ts.line=Scanline;\r |
156 | ts.hscroll=0;\r |
157 | \r |
158 | // Find name table line:\r |
159 | if (Pico.video.reg[12]&1)\r |
160 | {\r |
161 | ts.nametab=(pvid->reg[3]&0x3c)<<9; // 40-cell mode\r |
162 | ts.nametab+=(ts.line>>3)<<6;\r |
163 | }\r |
164 | else\r |
165 | {\r |
166 | ts.nametab=(pvid->reg[3]&0x3e)<<9; // 32-cell mode\r |
167 | ts.nametab+=(ts.line>>3)<<5;\r |
168 | }\r |
169 | \r |
170 | ts.xmask=0x3f;\r |
171 | ts.high=high;\r |
172 | \r |
173 | DrawStrip(ts);\r |
174 | return 0;\r |
175 | }\r |
176 | \r |
177 | static int DrawSprite(int sy,unsigned short *sprite,int high)\r |
178 | {\r |
179 | int sx=0,width=0,height=0;\r |
180 | int row=0,code=0;\r |
181 | unsigned int *pal=NULL;\r |
182 | int tile=0,delta=0;\r |
183 | int i=0;\r |
184 | \r |
185 | code=sprite[2];\r |
186 | if ((code>>15)!=high) { WrongPri=1; return 0; } // Wrong priority\r |
187 | \r |
188 | height=sprite[1]>>8;\r |
189 | width=(height>>2)&3; height&=3;\r |
190 | width++; height++; // Width and height in tiles\r |
191 | if (Scanline>=sy+(height<<3)) return 0; // Not on this line after all\r |
192 | \r |
193 | row=Scanline-sy; // Row of the sprite we are on\r |
194 | pal=Pico.highpal+((code>>9)&0x30); // Get palette pointer\r |
195 | if (code&0x1000) row=(height<<3)-1-row; // Flip Y\r |
196 | \r |
197 | tile=code&0x7ff; // Tile number\r |
198 | tile+=row>>3; // Tile number increases going down\r |
199 | delta=height; // Delta to increase tile by going right\r |
200 | if (code&0x0800) { tile+=delta*(width-1); delta=-delta; } // Flip X\r |
201 | \r |
202 | tile<<=4; tile+=(row&7)<<1; // Tile address\r |
203 | delta<<=4; // Delta of address\r |
204 | \r |
205 | sx=(sprite[3]&0x1ff)-0x78; // Get X coordinate + 8\r |
206 | \r |
207 | for (i=0; i<width; i++,sx+=8,tile+=delta)\r |
208 | {\r |
209 | if (sx<=0 || sx>=328) continue; // Offscreen\r |
210 | \r |
211 | tile&=0x7fff; // Clip tile address\r |
212 | if (code&0x0800) TileFlip(HighCol+24+sx,tile,pal);\r |
213 | else TileNorm(HighCol+24+sx,tile,pal);\r |
214 | }\r |
215 | \r |
216 | return 0;\r |
217 | }\r |
218 | \r |
219 | static int DrawAllSprites(int high)\r |
220 | {\r |
221 | struct PicoVideo *pvid=&Pico.video;\r |
222 | int table=0;\r |
223 | int i=0,link=0;\r |
224 | unsigned char spin[80]; // Sprite index\r |
225 | \r |
226 | WrongPri=0;\r |
227 | \r |
228 | table=pvid->reg[5]&0x7f;\r |
229 | if (pvid->reg[12]&1) table&=0x7e; // Lowest bit 0 in 40-cell mode\r |
230 | table<<=8; // Get sprite table address/2\r |
231 | \r |
232 | for (;;)\r |
233 | {\r |
234 | unsigned short *sprite=NULL;\r |
235 | \r |
236 | spin[i]=(unsigned char)link;\r |
237 | sprite=Pico.vram+((table+(link<<2))&0x7ffc); // Find sprite\r |
238 | \r |
239 | // Find next sprite\r |
240 | link=sprite[1]&0x7f;\r |
241 | if (link==0 || i>=79) break; // End of sprites\r |
242 | i++;\r |
243 | }\r |
244 | \r |
245 | // Go through sprites backwards:\r |
246 | for ( ;i>=0; i--)\r |
247 | {\r |
248 | unsigned short *sprite=NULL;\r |
249 | int sy=0;\r |
250 | \r |
251 | sprite=Pico.vram+((table+(spin[i]<<2))&0x7ffc); // Find sprite\r |
252 | \r |
253 | sy=(sprite[0]&0x1ff)-0x80; // Get Y coordinate\r |
254 | \r |
255 | if (Scanline>=sy && Scanline<sy+32) DrawSprite(sy,sprite,high); // Possibly on this line\r |
256 | }\r |
257 | \r |
258 | return 0;\r |
259 | }\r |
260 | \r |
261 | static void BackFill()\r |
262 | {\r |
263 | unsigned int back=0;\r |
264 | unsigned int *pd=NULL,*end=NULL;\r |
265 | \r |
266 | // Start with a blank scanline (background colour):\r |
267 | back=Pico.video.reg[7]&0x3f;\r |
268 | back=Pico.highpal[back];\r |
269 | back|=back<<16;\r |
270 | \r |
271 | pd= (unsigned int *)(HighCol+32);\r |
272 | end=(unsigned int *)(HighCol+32+320);\r |
273 | \r |
274 | do { pd[0]=pd[1]=pd[2]=pd[3]=back; pd+=4; } while (pd<end);\r |
275 | }\r |
276 | \r |
277 | static int DrawDisplay()\r |
278 | {\r |
279 | int win=0,edge=0,full=0;\r |
280 | int bhigh=1,ahigh=1,shigh=1;\r |
281 | \r |
282 | // Find out if the window is on this line:\r |
283 | win=Pico.video.reg[0x12];\r |
284 | edge=(win&0x1f)<<3;\r |
285 | \r |
286 | if (win&0x80) { if (Scanline>=edge) full=1; }\r |
287 | else { if (Scanline< edge) full=1; }\r |
288 | \r |
289 | if (PicoMask&0x04) { DrawLayer(1,0); bhigh=WrongPri; }\r |
290 | if (PicoMask&0x08) { if (full) DrawWindow(0); else DrawLayer(0,0); ahigh=WrongPri; }\r |
291 | if (PicoMask&0x10) { DrawAllSprites(0); shigh=WrongPri; }\r |
292 | \r |
293 | if (bhigh) if (PicoMask&0x20) DrawLayer(1,1);\r |
294 | if (ahigh) if (PicoMask&0x40) { if (full) DrawWindow(1); else DrawLayer(0,1); }\r |
295 | if (shigh) if (PicoMask&0x80) DrawAllSprites(1);\r |
296 | return 0;\r |
297 | }\r |
298 | \r |
299 | static int UpdatePalette()\r |
300 | {\r |
301 | int c=0;\r |
302 | \r |
303 | // Update palette:\r |
304 | for (c=0;c<64;c++) Pico.highpal[c]=(unsigned short)PicoCram(Pico.cram[c]);\r |
305 | Pico.m.dirtyPal=0;\r |
306 | \r |
307 | return 0;\r |
308 | }\r |
309 | \r |
310 | static int Overlay()\r |
311 | {\r |
312 | int col=0,x=0;\r |
313 | \r |
314 | if (PmovAction==0) return 0;\r |
315 | if (Scanline>=4) return 0;\r |
316 | \r |
317 | if (PmovAction&1) col =0x00f;\r |
318 | if (PmovAction&2) col|=0x0f0;\r |
319 | col=PicoCram(col);\r |
320 | \r |
321 | for (x=0;x<4;x++) HighCol[32+x]=(unsigned short)col;\r |
322 | \r |
323 | return 0;\r |
324 | }\r |
325 | \r |
326 | static int Skip=0;\r |
327 | \r |
328 | \r |
329 | int PicoLine(int scan)\r |
330 | {\r |
331 | if (Skip>0) { Skip--; return 0; } // Skip rendering lines\r |
332 | \r |
333 | Scanline=scan;\r |
334 | \r |
335 | if (Pico.m.dirtyPal) UpdatePalette();\r |
336 | \r |
337 | // Draw screen:\r |
338 | if (PicoMask&0x02) BackFill();\r |
339 | if (Pico.video.reg[1]&0x40) DrawDisplay();\r |
340 | \r |
341 | Overlay();\r |
342 | \r |
343 | if (Pico.video.reg[12]&1)\r |
344 | {\r |
345 | Skip=PicoScan(Scanline,HighCol+32); // 40-column mode\r |
346 | }\r |
347 | else\r |
348 | {\r |
349 | // Crop, centre and return 32-column mode\r |
350 | memset(HighCol, 0,64); // Left border\r |
351 | memset(HighCol+288,0,64); // Right border\r |
352 | Skip=PicoScan(Scanline,HighCol);\r |
353 | }\r |
354 | \r |
355 | return 0;\r |
356 | }\r |
357 | \r |