private void CastRay(int xOrig, int yOrig, int xDest, int yDest, int radiusSquared, bool lightWalls)
{
int xCur = xOrig;
int yCur = yOrig;
bool inMap = false;
bool blocked = false;
bool end = false;
var lineData = new BresenhamLineData();
InitLineData(xOrig, yOrig, xDest, yDest, lineData);
if (xCur.Between(0, Width) && yCur.Between(0, Height))
{
inMap = true;
Tiles[xCur, yCur].InView = true;
}
while (!end)
{
end = StepLineData(ref xCur, ref yCur, lineData);
if (radiusSquared > 0)
{
int curRadius = (xCur - xOrig) * (xCur - xOrig) + (yCur - yOrig) * (yCur - yOrig);
if (curRadius > radiusSquared)
{
return;
}
}
if (xCur.Between(0, Width) && yCur.Between(0, Height))
{
inMap = true;
if (!blocked && !Tiles[xCur, yCur].Transparent)
{
blocked = true;
}
else if (blocked)
{
return;
}
if (lightWalls || !blocked)
{
Tiles[xCur, yCur].InView = true;
}
}
else if (inMap)
{
return;
}
}
}
private void InitLineData(int xOrig, int yOrig, int xDest, int yDest, BresenhamLineData data)
{
data.OrigX = xOrig;
data.OrigY = yOrig;
data.DestX = xDest;
data.DestY = yDest;
data.DeltaX = xDest - xOrig;
data.DeltaY = yDest - yOrig;
if (data.DeltaX > 0)
{
data.StepX = 1;
}
else if (data.DeltaX < 0)
{
data.StepX = -1;
}
else
{
data.StepX = 0;
}
if (data.DeltaY > 0)
{
data.StepY = 1;
}
else if (data.DeltaY < 0)
{
data.StepY = -1;
}
else
{
data.StepY = 0;
}
if (data.StepX * data.DeltaX > data.StepY * data.DeltaY)
{
data.E = data.StepX * data.DeltaX;
data.DeltaX *= 2;
data.DeltaY *= 2;
}
else
{
data.E = data.StepY * data.DeltaY;
data.DeltaX *= 2;
data.DeltaY *= 2;
}
}
private bool StepLineData(ref int xCur, ref int yCur, BresenhamLineData data)
{
if (data.StepX * data.DeltaX > data.StepY * data.DeltaY)
{
if (data.OrigX == data.DestX)
{
return(true);
}
data.OrigX += data.StepX;
data.E -= data.StepY * data.DeltaY;
if (data.E < 0)
{
data.OrigY += data.StepY;
data.E += data.StepX * data.DeltaX;
}
}
else
{
if (data.OrigY == data.DestY)
{
return(true);
}
data.OrigY += data.StepY;
data.E -= data.StepX * data.DeltaX;
if (data.E < 0)
{
data.OrigX += data.StepX;
data.E += data.StepY * data.DeltaY;
}
}
xCur = data.OrigX;
yCur = data.OrigY;
return(false);
}
