/// <summary>
/// Renders to the screen buffer based on the current cycle
/// </summary>
public void RenderScreen(int toCycle)
{
// check boundaries
if (toCycle > FrameCycleLength)
{
toCycle = FrameCycleLength;
}
// render the required number of cycles
for (int t = LastTState; t < toCycle; t++)
{
if (!Border4T || (t & 3) == Border4TStage)
{
fetchBorder = BorderColor;
}
else
{
}
//fetchBorder = BorderColor;
// get the table entry
var item = RenderingTable.Renderer[t];
switch (item.RAction)
{
case RenderTable.RenderAction.None:
break;
case RenderTable.RenderAction.Border:
ScreenBuffer[item.LineOffset] = ULAPalette[fetchBorder];
ScreenBuffer[item.LineOffset + 1] = ULAPalette[fetchBorder];
break;
case RenderTable.RenderAction.BorderAndFetchByte1:
ScreenBuffer[item.LineOffset] = ULAPalette[fetchBorder];
ScreenBuffer[item.LineOffset + 1] = ULAPalette[fetchBorder];
fetchB1 = _machine.FetchScreenMemory(item.ByteAddress);
break;
case RenderTable.RenderAction.BorderAndFetchAttribute1:
ScreenBuffer[item.LineOffset] = ULAPalette[fetchBorder];
ScreenBuffer[item.LineOffset + 1] = ULAPalette[fetchBorder];
fetchA1 = _machine.FetchScreenMemory(item.AttributeAddress);
ProcessInkPaper(fetchA1);
break;
case RenderTable.RenderAction.Shift1AndFetchByte2:
ScreenBuffer[item.LineOffset] = ((fetchB1 & 0x80) != 0) ? palInk : palPaper;
ScreenBuffer[item.LineOffset + 1] = ((fetchB1 & 0x40) != 0) ? palInk : palPaper;
fetchB1 <<= 2;
fetchB2 = _machine.FetchScreenMemory(item.ByteAddress);
break;
case RenderTable.RenderAction.Shift1AndFetchAttribute2:
ScreenBuffer[item.LineOffset] = ((fetchB1 & 0x80) != 0) ? palInk : palPaper;
ScreenBuffer[item.LineOffset + 1] = ((fetchB1 & 0x40) != 0) ? palInk : palPaper;
fetchB1 <<= 2;
fetchA2 = _machine.FetchScreenMemory(item.AttributeAddress);
break;
case RenderTable.RenderAction.Shift1:
ScreenBuffer[item.LineOffset] = ((fetchB1 & 0x80) != 0) ? palInk : palPaper;
ScreenBuffer[item.LineOffset + 1] = ((fetchB1 & 0x40) != 0) ? palInk : palPaper;
fetchB1 <<= 2;
break;
case RenderTable.RenderAction.Shift1Last:
ScreenBuffer[item.LineOffset] = ((fetchB1 & 0x80) != 0) ? palInk : palPaper;
ScreenBuffer[item.LineOffset + 1] = ((fetchB1 & 0x40) != 0) ? palInk : palPaper;
fetchB1 <<= 2;
ProcessInkPaper(fetchA2);
break;
case RenderTable.RenderAction.Shift2:
ScreenBuffer[item.LineOffset] = ((fetchB2 & 0x80) != 0) ? palInk : palPaper;
ScreenBuffer[item.LineOffset + 1] = ((fetchB2 & 0x40) != 0) ? palInk : palPaper;
fetchB2 <<= 2;
break;
case RenderTable.RenderAction.Shift2AndFetchByte1:
ScreenBuffer[item.LineOffset] = ((fetchB2 & 0x80) != 0) ? palInk : palPaper;
ScreenBuffer[item.LineOffset + 1] = ((fetchB2 & 0x40) != 0) ? palInk : palPaper;
fetchB2 <<= 2;
fetchB1 = _machine.FetchScreenMemory(item.ByteAddress);
break;
case RenderTable.RenderAction.Shift2AndFetchAttribute1:
ScreenBuffer[item.LineOffset] = ((fetchB2 & 0x80) != 0) ? palInk : palPaper;
ScreenBuffer[item.LineOffset + 1] = ((fetchB2 & 0x40) != 0) ? palInk : palPaper;
fetchB2 <<= 2;
fetchA1 = _machine.FetchScreenMemory(item.AttributeAddress);
ProcessInkPaper(fetchA1);
break;
}
}
LastTState = toCycle;
}
/// <summary>
/// Updates the screen buffer based on the number of T-States supplied
/// </summary>
/// <param name="_tstates"></param>
public virtual void UpdateScreenBuffer(long _tstates)
{
if (_tstates < actualULAStart)
{
return;
}
else if (_tstates >= FrameLength)
{
_tstates = FrameLength - 1;
needsPaint = true;
}
//the additional 1 tstate is required to get correct number of bytes to output in ircontention.sna
elapsedTStates = (_tstates + 1 - lastTState) - 1;
//It takes 4 tstates to write 1 byte. Or, 2 pixels per t-state.
long numBytes = (elapsedTStates >> 2) + ((elapsedTStates % 4) > 0 ? 1 : 0);
int pixelData;
int pixel2Data = 0xff;
int attrData;
int attr2Data;
int bright;
int ink;
int paper;
int flash;
for (int i = 0; i < numBytes; i++)
{
if (tstateToDisp[lastTState] > 1)
{
screenByteCtr = tstateToDisp[lastTState] - 16384; //adjust for actual screen offset
pixelData = _machine.FetchScreenMemory((ushort)screenByteCtr); //screen[screenByteCtr];
attrData = _machine.FetchScreenMemory((ushort)(attr[screenByteCtr] - 16384)); //screen[attr[screenByteCtr] - 16384];
lastPixelValue = pixelData;
lastAttrValue = attrData;
bright = (attrData & 0x40) >> 3;
flash = (attrData & 0x80) >> 7;
ink = (attrData & 0x07);
paper = ((attrData >> 3) & 0x7);
int paletteInk = ULAPalette[ink + bright];
int palettePaper = ULAPalette[paper + bright];
if (flashOn && (flash != 0)) //swap paper and ink when flash is on
{
int temp = paletteInk;
paletteInk = palettePaper;
palettePaper = temp;
}
for (int a = 0; a < 8; ++a)
{
if ((pixelData & 0x80) != 0)
{
ScreenBuffer[ULAByteCtr++] = paletteInk;
lastAttrValue = ink;
//pixelIsPaper = false;
}
else
{
ScreenBuffer[ULAByteCtr++] = palettePaper;
lastAttrValue = paper;
}
pixelData <<= 1;
}
}
else if (tstateToDisp[lastTState] == 1)
{
int bor = ULAPalette[borderColour];
for (int g = 0; g < 8; g++)
{
ScreenBuffer[ULAByteCtr++] = bor;
}
}
lastTState += 4;
}
}
