public void Tick(World world, Shroud shroud)
{
Visible = true;
foreach (var pos in Footprint)
{
if (shroud.IsVisible(pos))
{
Visible = false;
break;
}
}
if (flashTicks > 0)
flashTicks--;
}
static int FoggedEdges(Shroud s, CPos p, bool useExtendedIndex)
{
if (!s.IsVisible(p.X, p.Y))
return 15;
// If a side is shrouded then we also count the corners
var u = 0;
if (!s.IsVisible(p.X, p.Y - 1)) u |= 0x13;
if (!s.IsVisible(p.X + 1, p.Y)) u |= 0x26;
if (!s.IsVisible(p.X, p.Y + 1)) u |= 0x4C;
if (!s.IsVisible(p.X - 1, p.Y)) u |= 0x89;
var uside = u & 0x0F;
if (!s.IsVisible(p.X - 1, p.Y - 1)) u |= 0x01;
if (!s.IsVisible(p.X + 1, p.Y - 1)) u |= 0x02;
if (!s.IsVisible(p.X + 1, p.Y + 1)) u |= 0x04;
if (!s.IsVisible(p.X - 1, p.Y + 1)) u |= 0x08;
// RA provides a set of frames for tiles with shrouded
// corners but unshrouded edges. We want to detect this
// situation without breaking the edge -> corner enabling
// in other combinations. The XOR turns off the corner
// bits that are enabled twice, which gives the behavior
// we want here.
return useExtendedIndex ? u ^ uside : u & 0x0F;
}
public void Tick(World world, Shroud shroud)
{
Visible = !Footprint.Any(c => shroud.IsVisible(c));
if (flashTicks > 0)
flashTicks--;
}
Sprite ChooseFog(Shroud s, int i, int j)
{
if (!s.IsVisible(i, j)) return shadowBits[0xf];
if (!s.IsExplored(i, j)) return shadowBits[0xf];
// bits are for unexploredness: up, right, down, left
var v = 0;
// bits are for unexploredness: TL, TR, BR, BL
var u = 0;
if (!s.IsVisible(i, j - 1)) { v |= 1; u |= 3; }
if (!s.IsVisible(i + 1, j)) { v |= 2; u |= 6; }
if (!s.IsVisible(i, j + 1)) { v |= 4; u |= 12; }
if (!s.IsVisible(i - 1, j)) { v |= 8; u |= 9; }
var uSides = u;
if (!s.IsVisible(i - 1, j - 1)) u |= 1;
if (!s.IsVisible(i + 1, j - 1)) u |= 2;
if (!s.IsVisible(i + 1, j + 1)) u |= 4;
if (!s.IsVisible(i - 1, j + 1)) u |= 8;
return shadowBits[SpecialShroudTiles[u ^ uSides][v]];
}