license info added to Pico directory

[cyclone68000.git] / Pico / Draw.cpp

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// This file is part of the PicoDrive Megadrive Emulator\r
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// This code is licensed under the GNU General Public License version 2.0 and the MAME License.\r
// You can choose the license that has the most advantages for you.\r
\r
// SVN repository can be found at http://code.google.com/p/cyclone68000/\r
\r
#include "PicoInt.h"\r
#ifndef __GNUC__\r
#pragma warning (disable:4706) // Disable assignment with conditional\r
#endif\r
\r
int (*PicoScan)(unsigned int num,unsigned short *data)=NULL;\r
\r
// Line colour indices - in the format 00ppcccc pp=palette, cccc=colour\r
static unsigned short HighCol[32+320+8]; // Gap for 32 column, and messy border on right\r
static int Scanline=0; // Scanline\r
\r
int PicoMask=0xfff; // Mask of which layers to draw\r
\r
static int TileNorm(unsigned short *pd,int addr,unsigned int *pal)\r
{\r
  unsigned int pack=0; unsigned int t=0;\r
\r
  pack=*(unsigned int *)(Pico.vram+addr); // Get 8 pixels\r
  if (pack)\r
  {\r
    t=pack&0x0000f000; if (t) { t=pal[t>>12]; pd[0]=(unsigned short)t; }\r
    t=pack&0x00000f00; if (t) { t=pal[t>> 8]; pd[1]=(unsigned short)t; }\r
    t=pack&0x000000f0; if (t) { t=pal[t>> 4]; pd[2]=(unsigned short)t; }\r
    t=pack&0x0000000f; if (t) { t=pal[t    ]; pd[3]=(unsigned short)t; }\r
    t=pack&0xf0000000; if (t) { t=pal[t>>28]; pd[4]=(unsigned short)t; }\r
    t=pack&0x0f000000; if (t) { t=pal[t>>24]; pd[5]=(unsigned short)t; }\r
    t=pack&0x00f00000; if (t) { t=pal[t>>20]; pd[6]=(unsigned short)t; }\r
    t=pack&0x000f0000; if (t) { t=pal[t>>16]; pd[7]=(unsigned short)t; }\r
    return 0;\r
  }\r
\r
  return 1; // Tile blank\r
}\r
\r
static int TileFlip(unsigned short *pd,int addr,unsigned int *pal)\r
{\r
  unsigned int pack=0; unsigned int t=0;\r
\r
  pack=*(unsigned int *)(Pico.vram+addr); // Get 8 pixels\r
  if (pack)\r
  {\r
    t=pack&0x000f0000; if (t) { t=pal[t>>16]; pd[0]=(unsigned short)t; }\r
    t=pack&0x00f00000; if (t) { t=pal[t>>20]; pd[1]=(unsigned short)t; }\r
    t=pack&0x0f000000; if (t) { t=pal[t>>24]; pd[2]=(unsigned short)t; }\r
    t=pack&0xf0000000; if (t) { t=pal[t>>28]; pd[3]=(unsigned short)t; }\r
    t=pack&0x0000000f; if (t) { t=pal[t    ]; pd[4]=(unsigned short)t; }\r
    t=pack&0x000000f0; if (t) { t=pal[t>> 4]; pd[5]=(unsigned short)t; }\r
    t=pack&0x00000f00; if (t) { t=pal[t>> 8]; pd[6]=(unsigned short)t; }\r
    t=pack&0x0000f000; if (t) { t=pal[t>>12]; pd[7]=(unsigned short)t; }\r
    return 0;\r
  }\r
  return 1; // Tile blank\r
}\r
\r
struct TileStrip\r
{\r
  int nametab; // Position in VRAM of name table (for this tile line)\r
  int line;    // Line number in pixels 0x000-0x3ff within the virtual tilemap \r
  int hscroll; // Horizontal scroll value in pixels for the line\r
  int xmask;   // X-Mask (0x1f - 0x7f) for horizontal wraparound in the tilemap\r
  int high;    // High or low tiles\r
};\r
\r
static int WrongPri=0; // 1 if there were tiles which are the wrong priority\r
\r
static int DrawStrip(struct TileStrip ts)\r
{\r
  int tilex=0,dx=0,ty=0;\r
  int blank=-1; // The tile we know is blank\r
\r
  WrongPri=0;\r
\r
  // Draw tiles across screen:\r
  tilex=(-ts.hscroll)>>3;\r
  ty=(ts.line&7)<<1; // Y-Offset into tile\r
  for (dx=((ts.hscroll-1)&7)+1; dx<328; dx+=8,tilex++)\r
  {\r
    int code=0,addr=0,zero=0;\r
    unsigned int *pal=NULL;\r
\r
    code=Pico.vram[ts.nametab+(tilex&ts.xmask)];\r
    if (code==blank) continue;\r
    if ((code>>15)!=ts.high) { WrongPri=1; continue; }\r
\r
    // Get tile address/2:\r
    addr=(code&0x7ff)<<4;\r
    if (code&0x1000) addr+=14-ty; else addr+=ty; // Y-flip\r
\r
    pal=Pico.highpal+((code>>9)&0x30);\r
\r
    if (code&0x0800) zero=TileFlip(HighCol+24+dx,addr,pal);\r
    else             zero=TileNorm(HighCol+24+dx,addr,pal);\r
\r
    if (zero) blank=code; // We know this tile is blank now\r
  }\r
\r
  return 0;\r
}\r
\r
static int DrawLayer(int plane,int high)\r
{\r
  struct PicoVideo *pvid=&Pico.video;\r
  static char shift[4]={5,6,6,7}; // 32,64 or 128 sized tilemaps\r
  struct TileStrip ts;\r
\r
  // Work out the TileStrip to draw\r
\r
  // Get vertical scroll value:\r
  int vscroll=Pico.vsram[plane];\r
\r
  int htab=pvid->reg[13]<<9; // Horizontal scroll table address\r
  if ( pvid->reg[11]&2)     htab+=Scanline<<1; // Offset by line\r
  if ((pvid->reg[11]&1)==0) htab&=~0xf; // Offset by tile\r
  htab+=plane; // A or B\r
\r
  // Get horizontal scroll value\r
  ts.hscroll=Pico.vram[htab&0x7fff];\r
\r
  // Work out the name table size: 32 64 or 128 tiles (0-3)\r
  int width=pvid->reg[16];\r
  int height=(width>>4)&3; width&=3;\r
\r
  ts.xmask=(1<<shift[width ])-1; // X Mask in tiles\r
  int ymask=(8<<shift[height])-1; // Y Mask in pixels\r
\r
  // Find name table:\r
  if (plane==0) ts.nametab=(pvid->reg[2]&0x38)<< 9; // A\r
  else          ts.nametab=(pvid->reg[4]&0x07)<<12; // B\r
\r
  // Find the line in the name table\r
  ts.line=(vscroll+Scanline)&ymask;\r
  ts.nametab+=(ts.line>>3)<<shift[width];\r
\r
  ts.high=high;\r
\r
  DrawStrip(ts);\r
  return 0;\r
}\r
\r
static int DrawWindow(int high)\r
{\r
  struct PicoVideo *pvid=&Pico.video;\r
  struct TileStrip ts;\r
\r
  ts.line=Scanline;\r
  ts.hscroll=0;\r
\r
  // Find name table line:\r
  if (Pico.video.reg[12]&1)\r
  {\r
    ts.nametab=(pvid->reg[3]&0x3c)<<9; // 40-cell mode\r
    ts.nametab+=(ts.line>>3)<<6;\r
  }\r
  else\r
  {\r
    ts.nametab=(pvid->reg[3]&0x3e)<<9; // 32-cell mode\r
    ts.nametab+=(ts.line>>3)<<5;\r
  }\r
\r
  ts.xmask=0x3f;\r
  ts.high=high;\r
\r
  DrawStrip(ts);\r
  return 0;\r
}\r
\r
static int DrawSprite(int sy,unsigned short *sprite,int high)\r
{\r
  int sx=0,width=0,height=0;\r
  int row=0,code=0;\r
  unsigned int *pal=NULL;\r
  int tile=0,delta=0;\r
  int i=0;\r
\r
  code=sprite[2];\r
  if ((code>>15)!=high) { WrongPri=1; return 0; } // Wrong priority\r
\r
  height=sprite[1]>>8;\r
  width=(height>>2)&3; height&=3;\r
  width++; height++; // Width and height in tiles\r
  if (Scanline>=sy+(height<<3)) return 0; // Not on this line after all\r
\r
  row=Scanline-sy; // Row of the sprite we are on\r
  pal=Pico.highpal+((code>>9)&0x30); // Get palette pointer\r
  if (code&0x1000) row=(height<<3)-1-row; // Flip Y\r
\r
  tile=code&0x7ff; // Tile number\r
  tile+=row>>3; // Tile number increases going down\r
  delta=height; // Delta to increase tile by going right\r
  if (code&0x0800) { tile+=delta*(width-1); delta=-delta; } // Flip X\r
\r
  tile<<=4; tile+=(row&7)<<1; // Tile address\r
  delta<<=4; // Delta of address\r
\r
  sx=(sprite[3]&0x1ff)-0x78; // Get X coordinate + 8\r
\r
  for (i=0; i<width; i++,sx+=8,tile+=delta)\r
  {\r
    if (sx<=0 || sx>=328) continue; // Offscreen\r
\r
    tile&=0x7fff; // Clip tile address\r
    if (code&0x0800) TileFlip(HighCol+24+sx,tile,pal);\r
    else             TileNorm(HighCol+24+sx,tile,pal);\r
  }\r
\r
  return 0;\r
}\r
\r
static int DrawAllSprites(int high)\r
{\r
  struct PicoVideo *pvid=&Pico.video;\r
  int table=0;\r
  int i=0,link=0;\r
  unsigned char spin[80]; // Sprite index\r
\r
  WrongPri=0;\r
\r
  table=pvid->reg[5]&0x7f;\r
  if (pvid->reg[12]&1) table&=0x7e; // Lowest bit 0 in 40-cell mode\r
  table<<=8; // Get sprite table address/2\r
\r
  for (;;)\r
  {\r
    unsigned short *sprite=NULL;\r
    \r
    spin[i]=(unsigned char)link;\r
    sprite=Pico.vram+((table+(link<<2))&0x7ffc); // Find sprite\r
\r
    // Find next sprite\r
    link=sprite[1]&0x7f;\r
    if (link==0 || i>=79) break; // End of sprites\r
    i++;\r
  }\r
\r
  // Go through sprites backwards:\r
  for ( ;i>=0; i--)\r
  {\r
    unsigned short *sprite=NULL;\r
    int sy=0;\r
    \r
    sprite=Pico.vram+((table+(spin[i]<<2))&0x7ffc); // Find sprite\r
\r
    sy=(sprite[0]&0x1ff)-0x80; // Get Y coordinate\r
\r
    if (Scanline>=sy && Scanline<sy+32) DrawSprite(sy,sprite,high); // Possibly on this line\r
  }\r
\r
  return 0;\r
}\r
\r
static void BackFill()\r
{\r
  unsigned int back=0;\r
  unsigned int *pd=NULL,*end=NULL;\r
\r
  // Start with a blank scanline (background colour):\r
  back=Pico.video.reg[7]&0x3f;\r
  back=Pico.highpal[back];\r
  back|=back<<16;\r
\r
  pd= (unsigned int *)(HighCol+32);\r
  end=(unsigned int *)(HighCol+32+320);\r
\r
  do { pd[0]=pd[1]=pd[2]=pd[3]=back; pd+=4; } while (pd<end);\r
}\r
\r
static int DrawDisplay()\r
{\r
  int win=0,edge=0,full=0;\r
  int bhigh=1,ahigh=1,shigh=1;\r
\r
  // Find out if the window is on this line:\r
  win=Pico.video.reg[0x12];\r
  edge=(win&0x1f)<<3;\r
\r
  if (win&0x80) { if (Scanline>=edge) full=1; }\r
  else          { if (Scanline< edge) full=1; }\r
\r
  if (PicoMask&0x04) { DrawLayer(1,0); bhigh=WrongPri; }\r
  if (PicoMask&0x08) { if (full) DrawWindow(0); else DrawLayer(0,0);  ahigh=WrongPri; }\r
  if (PicoMask&0x10) { DrawAllSprites(0); shigh=WrongPri; }\r
  \r
  if (bhigh) if (PicoMask&0x20) DrawLayer(1,1);\r
  if (ahigh) if (PicoMask&0x40) { if (full) DrawWindow(1); else DrawLayer(0,1); }\r
  if (shigh) if (PicoMask&0x80) DrawAllSprites(1);\r
  return 0;\r
}\r
\r
static int UpdatePalette()\r
{\r
  int c=0;\r
\r
  // Update palette:\r
  for (c=0;c<64;c++) Pico.highpal[c]=(unsigned short)PicoCram(Pico.cram[c]);\r
  Pico.m.dirtyPal=0;\r
\r
  return 0;\r
}\r
\r
static int Overlay()\r
{\r
  int col=0,x=0;\r
\r
  if (PmovAction==0) return 0;\r
  if (Scanline>=4) return 0;\r
\r
  if (PmovAction&1) col =0x00f;\r
  if (PmovAction&2) col|=0x0f0;\r
  col=PicoCram(col);\r
\r
  for (x=0;x<4;x++) HighCol[32+x]=(unsigned short)col;\r
\r
  return 0;\r
}\r
\r
static int Skip=0;\r
\r
\r
int PicoLine(int scan)\r
{\r
  if (Skip>0) { Skip--; return 0; } // Skip rendering lines\r
\r
  Scanline=scan;\r
\r
  if (Pico.m.dirtyPal) UpdatePalette();\r
\r
  // Draw screen:\r
  if (PicoMask&0x02) BackFill();\r
  if (Pico.video.reg[1]&0x40) DrawDisplay();\r
\r
  Overlay();\r
\r
  if (Pico.video.reg[12]&1)\r
  {\r
    Skip=PicoScan(Scanline,HighCol+32); // 40-column mode\r
  }\r
  else\r
  {\r
    // Crop, centre and return 32-column mode\r
    memset(HighCol,    0,64); // Left border\r
    memset(HighCol+288,0,64); // Right border\r
    Skip=PicoScan(Scanline,HighCol);\r
  }\r
\r
  return 0;\r
}\r
\r