public bool Tick()
{
_fetcher.Tick();
if (_lcdc.IsBgAndWindowDisplay() || _gbc)
{
if (_fifo.GetLength() <= 8)
{
return(true);
}
if (_droppedPixels < _r.Get(GpuRegister.Scx) % 8)
{
_fifo.DropPixel();
_droppedPixels++;
return(true);
}
if (!_window && _lcdc.IsWindowDisplay() && _r.Get(GpuRegister.Ly) >= _r.Get(GpuRegister.Wy) &&
_x == _r.Get(GpuRegister.Wx) - 7)
{
_window = true;
StartFetchingWindow();
return(true);
}
}
if (_lcdc.IsObjDisplay())
{
if (_fetcher.SpriteInProgress())
{
return(true);
}
var spriteAdded = false;
for (var i = 0; i < _sprites.Length; i++)
{
var s = _sprites[i];
if (s == null)
{
continue;
}
if (_x == 0 && s.GetX() < 8)
{
_fetcher.AddSprite(s, 8 - s.GetX(), i);
spriteAdded = true;
_sprites[i] = null;
}
else if (s.GetX() - 8 == _x)
{
_fetcher.AddSprite(s, 0, i);
spriteAdded = true;
_sprites[i] = null;
}
if (spriteAdded)
{
return(true);
}
}
}
_fifo.PutPixelToScreen();
if (++_x == 160)
{
return(false);
}
return(true);
}
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;
}
}