// VisualBoyAdvance - Nintendo Gameboy/GameboyAdvance (TM) emulator.
// Copyright (C) 1999-2003 Forgotten
// Copyright (C) 2004 Forgotten and the VBA development team

// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or(at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation,
// Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

#include <string.h>

#include "../agb/GBA.h"
#include "gbGlobals.h"
#include "gbSGB.h"

u8 gbInvertTab[256] = {
                        0x00,0x80,0x40,0xc0,0x20,0xa0,0x60,0xe0,
                        0x10,0x90,0x50,0xd0,0x30,0xb0,0x70,0xf0,
                        0x08,0x88,0x48,0xc8,0x28,0xa8,0x68,0xe8,
                        0x18,0x98,0x58,0xd8,0x38,0xb8,0x78,0xf8,
                        0x04,0x84,0x44,0xc4,0x24,0xa4,0x64,0xe4,
                        0x14,0x94,0x54,0xd4,0x34,0xb4,0x74,0xf4,
                        0x0c,0x8c,0x4c,0xcc,0x2c,0xac,0x6c,0xec,
                        0x1c,0x9c,0x5c,0xdc,0x3c,0xbc,0x7c,0xfc,
                        0x02,0x82,0x42,0xc2,0x22,0xa2,0x62,0xe2,
                        0x12,0x92,0x52,0xd2,0x32,0xb2,0x72,0xf2,
                        0x0a,0x8a,0x4a,0xca,0x2a,0xaa,0x6a,0xea,
                        0x1a,0x9a,0x5a,0xda,0x3a,0xba,0x7a,0xfa,
                        0x06,0x86,0x46,0xc6,0x26,0xa6,0x66,0xe6,
                        0x16,0x96,0x56,0xd6,0x36,0xb6,0x76,0xf6,
                        0x0e,0x8e,0x4e,0xce,0x2e,0xae,0x6e,0xee,
                        0x1e,0x9e,0x5e,0xde,0x3e,0xbe,0x7e,0xfe,
                        0x01,0x81,0x41,0xc1,0x21,0xa1,0x61,0xe1,
                        0x11,0x91,0x51,0xd1,0x31,0xb1,0x71,0xf1,
                        0x09,0x89,0x49,0xc9,0x29,0xa9,0x69,0xe9,
                        0x19,0x99,0x59,0xd9,0x39,0xb9,0x79,0xf9,
                        0x05,0x85,0x45,0xc5,0x25,0xa5,0x65,0xe5,
                        0x15,0x95,0x55,0xd5,0x35,0xb5,0x75,0xf5,
                        0x0d,0x8d,0x4d,0xcd,0x2d,0xad,0x6d,0xed,
                        0x1d,0x9d,0x5d,0xdd,0x3d,0xbd,0x7d,0xfd,
                        0x03,0x83,0x43,0xc3,0x23,0xa3,0x63,0xe3,
                        0x13,0x93,0x53,0xd3,0x33,0xb3,0x73,0xf3,
                        0x0b,0x8b,0x4b,0xcb,0x2b,0xab,0x6b,0xeb,
                        0x1b,0x9b,0x5b,0xdb,0x3b,0xbb,0x7b,0xfb,
                        0x07,0x87,0x47,0xc7,0x27,0xa7,0x67,0xe7,
                        0x17,0x97,0x57,0xd7,0x37,0xb7,0x77,0xf7,
                        0x0f,0x8f,0x4f,0xcf,0x2f,0xaf,0x6f,0xef,
                        0x1f,0x9f,0x5f,0xdf,0x3f,0xbf,0x7f,0xff
                      };

u16 gbLineMix[160];

void gbRenderLine()
{
  u8 * bank0;
  u8 * bank1;
  if(gbCgbMode)
    {
      bank0 = &gbVram[0x0000];
      bank1 = &gbVram[0x2000];
    }
  else
    {
      bank0 = &gbMemory[0x8000];
      bank1 = NULL;
    }

  int tile_map = 0x1800;
  if((register_LCDC & 8) != 0)
    tile_map = 0x1c00;

  int tile_pattern = 0x0800;

  if((register_LCDC & 16) != 0)
    tile_pattern = 0x0000;

  int x = 0;
  int y = register_LY;

  if(y >= 144)
    return;

  //  int yLine = (y + gbBorderRowSkip) * gbBorderLineSkip;

  int sx = register_SCX;
  int sy = register_SCY;

  sy+=y;

  sy &= 255;

  int tx = sx >> 3;
  int ty = sy >> 3;

  int bx = 1 << (7 - (sx & 7));
  int by = sy & 7;

  int tile_map_line_y = tile_map + ty * 32;

  int tile_map_address = tile_map_line_y + tx;

  u8 attrs = 0;
  if(bank1 != NULL)
    attrs = bank1[tile_map_address];

  u8 tile = bank0[tile_map_address];

  tile_map_address++;

  if((register_LCDC & 16) == 0)
    {
      if(tile < 128) tile += 128;
      else tile -= 128;
    }

  int tile_pattern_address = tile_pattern + tile * 16 + by*2;

  if(register_LCDC & 0x80)
    {
      if((register_LCDC & 0x01 || gbCgbMode) && (layerSettings & 0x0100))
        {
          while(x < 160)
            {
              u8 tile_a = 0;
              u8 tile_b = 0;

              if(attrs & 0x40)
                {
                  tile_pattern_address = tile_pattern + tile * 16 + (7-by)*2;
                }

              if(attrs & 0x08)
                {
                  tile_a = bank1[tile_pattern_address++];
                  tile_b = bank1[tile_pattern_address];
                }
              else
                {
                  tile_a = bank0[tile_pattern_address++];
                  tile_b = bank0[tile_pattern_address];
                }

              if(attrs & 0x20)
                {
                  tile_a = gbInvertTab[tile_a];
                  tile_b = gbInvertTab[tile_b];
                }

              while(bx > 0)
                {
                  u8 c = (tile_a & bx) ? 1 : 0;
                  c += ((tile_b & bx) ? 2 : 0);

                  gbLineBuffer[x] = c; // mark the gbLineBuffer color

                  if(attrs & 0x80)
                    gbLineBuffer[x] |= 0x300;

                  if(gbCgbMode)
                    {
                      c = c + (attrs & 7)*4;
                    }
                  else
                    {
                      c = gbBgp[c];
                      if(gbSgbMode && !gbCgbMode)
                        {
                          int dx = x >> 3;
                          int dy = y >> 3;

                          int palette = gbSgbATF[dy * 20 + dx];

                          if(c == 0)
                            palette = 0;

                          c = c + 4*palette;
                        }
                    }
                  gbLineMix[x] = gbColorOption ? gbColorFilter[gbPalette[c]] :
                                 gbPalette[c];
                  x++;
                  if(x >= 160)
                    break;
                  bx >>= 1;
                }
              tx++;
              if(tx == 32)
                tx = 0;
              bx = 128;

              if(bank1)
                attrs = bank1[tile_map_line_y + tx];

              tile = bank0[tile_map_line_y + tx];

              if((register_LCDC & 16) == 0)
                {
                  if(tile < 128) tile += 128;
                  else tile -= 128;
                }
              tile_pattern_address = tile_pattern + tile * 16 + by * 2;
            }
        }
      else
        {
          for(int i = 0; i < 160; i++)
            {
              gbLineMix[i] = gbPalette[0];
              gbLineBuffer[i] = 0;
            }
        }

      // do the window display
      if((register_LCDC & 0x20) && (layerSettings & 0x2000))
        {
          int wy = register_WY;

          if(y >= wy)
            {
              int wx = register_WX;
              wx -= 7;

              if( wx <= 159 && gbWindowLine <= 143)
                {

                  tile_map = 0x1800;

                  if((register_LCDC & 0x40) != 0)
                    tile_map = 0x1c00;

                  if(gbWindowLine == -1)
                    {
                      gbWindowLine = 0;
                    }

                  tx = 0;
                  ty = gbWindowLine >> 3;

                  bx = 128;
                  by = gbWindowLine & 7;

                  if(wx < 0)
                    {
                      bx >>= (-wx);
                      wx = 0;
                    }

                  tile_map_line_y = tile_map + ty * 32;

                  tile_map_address = tile_map_line_y + tx;

                  x = wx;

                  tile = bank0[tile_map_address];
                  u8 attrs = 0;
                  if(bank1)
                    attrs = bank1[tile_map_address];
                  tile_map_address++;

                  if((register_LCDC & 16) == 0)
                    {
                      if(tile < 128) tile += 128;
                      else tile -= 128;
                    }

                  tile_pattern_address = tile_pattern + tile * 16 + by*2;

                  while(x < 160)
                    {
                      u8 tile_a = 0;
                      u8 tile_b = 0;

                      if(attrs & 0x40)
                        {
                          tile_pattern_address = tile_pattern + tile * 16 + (7-by)*2;
                        }

                      if(attrs & 0x08)
                        {
                          tile_a = bank1[tile_pattern_address++];
                          tile_b = bank1[tile_pattern_address];
                        }
                      else
                        {
                          tile_a = bank0[tile_pattern_address++];
                          tile_b = bank0[tile_pattern_address];
                        }

                      if(attrs & 0x20)
                        {
                          tile_a = gbInvertTab[tile_a];
                          tile_b = gbInvertTab[tile_b];
                        }

                      while(bx > 0)
                        {
                          u8 c = (tile_a & bx) != 0 ? 1 : 0;
                          c += ((tile_b & bx) != 0 ? 2 : 0);

                          if(attrs & 0x80)
                            gbLineBuffer[x] = 0x300 + c;
                          else
                            gbLineBuffer[x] = 0x100 + c;

                          if(gbCgbMode)
                            {
                              c = c + (attrs & 7) * 4;
                            }
                          else
                            {
                              c = gbBgp[c];
                              if(gbSgbMode && ! gbCgbMode)
                                {
                                  int dx = x >> 3;
                                  int dy = y >> 3;

                                  int palette = gbSgbATF[dy * 20 + dx];

                                  if(c == 0)
                                    palette = 0;

                                  c = c + 4*palette;
                                }
                            }
                          gbLineMix[x] = gbColorOption ? gbColorFilter[gbPalette[c]] :
                                         gbPalette[c];
                          x++;
                          if(x >= 160)
                            break;
                          bx >>= 1;
                        }
                      tx++;
                      if(tx == 32)
                        tx = 0;
                      bx = 128;
                      tile = bank0[tile_map_line_y + tx];
                      if(bank1)
                        attrs = bank1[tile_map_line_y + tx];

                      if((register_LCDC & 16) == 0)
                        {
                          if(tile < 128) tile += 128;
                          else tile -= 128;
                        }
                      tile_pattern_address = tile_pattern + tile * 16 + by * 2;
                    }
                  gbWindowLine++;
                }
            }
        }
    }
  else
    {
      for(int i = 0; i < 160; i++)
        {
          gbLineMix[i] = gbPalette[0];
          gbLineBuffer[i] = 0;
        }
    }
}

void gbDrawSpriteTile(int tile, int x,int y,int t, int flags,
                      int size,int spriteNumber)
{
  u8 * bank0;
  u8 * bank1;
  if(gbCgbMode)
    {
      if(register_VBK & 1)
        {
          bank0 = &gbVram[0x0000];
          bank1 = &gbVram[0x2000];
        }
      else
        {
          bank0 = &gbVram[0x0000];
          bank1 = &gbVram[0x2000];
        }
    }
  else
    {
      bank0 = &gbMemory[0x8000];
      bank1 = NULL;
    }

  int init = 0x0000;

  //  int yLine = (y+gbBorderRowSkip) * gbBorderLineSkip;

  u8 *pal = gbObp0;

  int flipx = (flags & 0x20);
  int flipy = (flags & 0x40);

  if((flags & 0x10))
    pal = gbObp1;

  if(flipy)
    {
      t = (size ? 15 : 7) - t;
    }

  int prio =  flags & 0x80;

  int address = init + tile * 16 + 2*t;
  int a = 0;
  int b = 0;

  if(gbCgbMode && flags & 0x08)
    {
      a = bank1[address++];
      b = bank1[address++];
    }
  else
    {
      a = bank0[address++];
      b = bank0[address++];
    }

  for(int xx = 0; xx < 8; xx++)
    {
      u8 mask = 1 << (7-xx);
      u8 c = 0;
      if( (a & mask))
        c++;
      if( (b & mask))
        c+=2;

      if(c==0) continue;

      int xxx = xx+x;
      if(flipx)
        xxx = (7-xx+x);

      if(xxx < 0 || xxx > 159)
        continue;

      u16 color = gbLineBuffer[xxx];

      if(prio)
        {
          if(color < 0x200 && ((color & 0xFF) != 0))
            continue;
        }
      if(color >= 0x300 && color != 0x300)
        continue;
      else if(color >= 0x200 && color < 0x300)
        {
          int sprite = color & 0xff;

          int spriteX = gbMemory[0xfe00 + 4 * sprite + 1] - 8;

          if(spriteX == x)
            {
              if(sprite < spriteNumber)
                continue;
            }
          else
            {
              if(gbCgbMode)
                {
                  if(sprite < spriteNumber)
                    continue;
                }
              else
                {
                  if(spriteX < x+8)
                    continue;
                }
            }
        }


      gbLineBuffer[xxx] = 0x200 + spriteNumber;

      // make sure that sprites will work even in CGB mode
      if(gbCgbMode)
        {
          c = c + (flags & 0x07)*4 + 32;
        }
      else
        {
          c = pal[c];

          if(gbSgbMode && !gbCgbMode)
            {
              int dx = xxx >> 3;
              int dy = y >> 3;

              int palette = gbSgbATF[dy * 20 + dx];

              if(c == 0)
                palette = 0;

              c = c + 4*palette;
            }
          else
            {
              c += 4;
            }
        }

      gbLineMix[xxx] = gbColorOption ? gbColorFilter[gbPalette[c]] :
                       gbPalette[c];
    }
}

void gbDrawSprites()
{
  int x = 0;
  int y = 0;
  int count = 0;

  int size = (register_LCDC & 4);

  if(!(register_LCDC & 0x80))
    return;

  if((register_LCDC & 2) && (layerSettings & 0x1000))
    {
      int yc = register_LY;

      int address = 0xfe00;
      for(int i = 0; i < 40; i++)
        {
          y = gbMemory[address++];
          x = gbMemory[address++];
          int tile = gbMemory[address++];
          if(size)
            tile &= 254;
          int flags = gbMemory[address++];

          if(x > 0 && y > 0 && x < 168 && y < 160)
            {
              // check if sprite intersects current line
              int t = yc -y + 16;
              if(size && t >=0 && t < 16)
                {
                  gbDrawSpriteTile(tile,x-8,yc,t,flags,size,i);
                  count++;
                }
              else if(!size && t >= 0 && t < 8)
                {
                  gbDrawSpriteTile(tile, x-8, yc, t, flags,size,i);
                  count++;
                }
            }
          // sprite limit reached!
          if(count >= 10)
            break;
        }
    }
}