private static void CastPartialLight(Loc rectStart, Loc rectSize, Loc start, Grid.LocTest checkBlock, LightOperation lightOp, int startColumn, int startSlope, int endSlope, Dir8 dir)
{
// Set true if the previous cell we encountered was blocked.
bool prevBlocked = false;
int savedRightSlope = -SLOPE_GRANULARITY;
int colVal = OctantTransform[(int)dir, 0] != 0 ? OctantTransform[(int)dir, 0] : OctantTransform[(int)dir, 2];
Loc colDiff = new Loc();
if (colVal > 0)
{
colDiff = rectStart + rectSize - start - new Loc(1);
}
else
{
colDiff = start - rectStart;
}
int maxCol = OctantTransform[(int)dir, 0] != 0 ? colDiff.X : colDiff.Y;
int rowVal = OctantTransform[(int)dir, 3] != 0 ? OctantTransform[(int)dir, 3] : OctantTransform[(int)dir, 1];
Loc rowDiff = new Loc();
if (rowVal > 0)
{
rowDiff = rectStart + rectSize - start - new Loc(1);
}
else
{
rowDiff = start - rectStart;
}
int maxRow = OctantTransform[(int)dir, 3] != 0 ? rowDiff.Y : rowDiff.X;
for (int currentCol = startColumn; currentCol <= maxCol; currentCol++)
{
int xc = currentCol;
for (int yc = Math.Min(maxRow, currentCol); yc >= 0; yc--)
{
int gridX = start.X + xc * OctantTransform[(int)dir, 0] + yc * OctantTransform[(int)dir, 1];
int gridY = start.Y + xc * OctantTransform[(int)dir, 2] + yc * OctantTransform[(int)dir, 3];
//due to safeguards, this block should never be hit
if (!Collision.InBounds(rectStart, rectSize, new Loc(gridX, gridY)))
{
continue;
}
int leftBlockSlope = (yc * SLOPE_GRANULARITY + SLOPE_GRANULARITY / 2) * 2 / (xc * 2 - 1);
int rightBlockSlope = (yc * SLOPE_GRANULARITY - SLOPE_GRANULARITY / 2) * 2 / (xc * 2 + 1);
if (rightBlockSlope > startSlope) // Block is above the left edge of our view area; skip.
{
continue;
}
else if (leftBlockSlope < endSlope) // Block is below the right edge of our view area; we're done.
{
break;
}
float lighting = 1f;
if (leftBlockSlope > startSlope) // Block is above the left edge of our view area; skip.
{
lighting = 0.5f;
}
else if (rightBlockSlope < endSlope) // Block is below the right edge of our view area; we're done.
{
lighting = 0.5f;
}
if (((int)dir % 2 == 0 || yc != 0) && ((int)dir % 2 == 1 || yc != currentCol))
{
lightOp(gridX, gridY, lighting);
}
bool curBlocked = checkBlock(new Loc(gridX, gridY));
if (prevBlocked)
{
if (curBlocked)
{
savedRightSlope = rightBlockSlope;
}
else
{
prevBlocked = false;
startSlope = savedRightSlope;
}
}
else
{
if (curBlocked)
{
if (leftBlockSlope <= startSlope)
{
CastPartialLight(rectStart, rectSize, start, checkBlock, lightOp, currentCol + 1, startSlope, leftBlockSlope, dir);
}
prevBlocked = true;
savedRightSlope = rightBlockSlope;
}
}
}
if (prevBlocked)
{
break;
}
}
}
public static void CalculateAnalogFOV(Loc rectStart, Loc rectSize, Loc start, Grid.LocTest checkBlock, LightOperation lightOp)
{
// Viewer's cell is always visible.
if (Collision.InBounds(rectStart, rectSize, start))
{
lightOp(start.X, start.Y, 1f);
}
for (int dir = 0; dir < DirExt.DIR8_COUNT; dir++)
{
CastPartialLight(rectStart, rectSize, start, checkBlock, lightOp, 1, 3 * SLOPE_GRANULARITY, -SLOPE_GRANULARITY, (Dir8)dir);
}
}
