public void Tick()
{
if (_fetchingDisabled && _state == State.ReadTileId)
{
if (_fifo.GetLength() <= 8)
{
_fifo.Enqueue8Pixels(EmptyPixelLine, _tileAttributes);
}
return;
}
if (--_divider == 0)
{
_divider = 2;
}
else
{
return;
}
stateSwitch:
switch (_state)
{
case State.ReadTileId:
_tileId = _videoRam0.GetByte(_mapAddress + _xOffset);
_tileAttributes = _gbc
? TileAttributes.ValueOf(_videoRam1.GetByte(_mapAddress + _xOffset))
: TileAttributes.Empty;
_state = State.ReadData1;
break;
case State.ReadData1:
_tileData1 = GetTileData(_tileId, _tileLine, 0, _tileDataAddress, _tileIdSigned, _tileAttributes, 8);
_state = State.ReadData2;
break;
case State.ReadData2:
_tileData2 = GetTileData(_tileId, _tileLine, 1, _tileDataAddress, _tileIdSigned, _tileAttributes, 8);
_state = State.Push;
goto stateSwitch; // Sorry mum
case State.Push:
if (_fifo.GetLength() <= 8)
{
_fifo.Enqueue8Pixels(Zip(_tileData1, _tileData2, _tileAttributes.IsXFlip()), _tileAttributes);
_xOffset = (_xOffset + 1) % 0x20;
_state = State.ReadTileId;
}
break;
case State.ReadSpriteTileId:
_tileId = _oemRam.GetByte(_sprite.GetAddress() + 2);
_state = State.ReadSpriteFlags;
break;
case State.ReadSpriteFlags:
_spriteAttributes = TileAttributes.ValueOf(_oemRam.GetByte(_sprite.GetAddress() + 3));
_state = State.ReadSpriteData1;
break;
case State.ReadSpriteData1:
if (_lcdc.GetSpriteHeight() == 16)
{
_tileId &= 0xfe;
}
_tileData1 = GetTileData(_tileId, _spriteTileLine, 0, 0x8000, false, _spriteAttributes,
_lcdc.GetSpriteHeight());
_state = State.ReadSpriteData2;
break;
case State.ReadSpriteData2:
_tileData2 = GetTileData(_tileId, _spriteTileLine, 1, 0x8000, false, _spriteAttributes,
_lcdc.GetSpriteHeight());
_state = State.PushSprite;
break;
case State.PushSprite:
_fifo.SetOverlay(Zip(_tileData1, _tileData2, _spriteAttributes.IsXFlip()), _spriteOffset,
_spriteAttributes, _spriteOamIndex);
_state = State.ReadTileId;
break;
}
}
