/**
* Given a grid of passable/impassable navcells (based on some passability mask),
* computes a new grid where a navcell is impassable (per that mask) if
* it is <=clearance navcells away from an impassable navcell in the original grid.
* The results are ORed onto the original grid.
*
* This is used for adding clearance onto terrain-based navcell passability.
*
* TODO PATHFINDER: might be nicer to get rounded corners by measuring clearances as
* Euclidean distances; currently it effectively does dist=max(dx,dy) instead.
* This would only really be a problem for big clearances.
*/
static void ExpandImpassableCells(Grid<u16>& grid, u16 clearance, pass_class_t mask)
{
PROFILE3("ExpandImpassableCells");
u16 w = grid.m_W;
u16 h = grid.m_H;
// First expand impassable cells horizontally into a temporary 1-bit grid
Grid<u8> tempGrid(w, h);
for (u16 j = 0; j < h; ++j)
{
// New cell (i,j) is blocked if (i',j) blocked for any i-clearance <= i' <= i+clearance
// Count the number of blocked cells around i=0
u16 numBlocked = 0;
for (u16 i = 0; i <= clearance && i < w; ++i)
if (!IS_PASSABLE(grid.get(i, j), mask))
++numBlocked;
for (u16 i = 0; i < w; ++i)
{
// Store a flag if blocked by at least one nearby cell
if (numBlocked)
tempGrid.set(i, j, 1);
// Slide the numBlocked window along:
// remove the old i-clearance value, add the new (i+1)+clearance
// (avoiding overflowing the grid)
if (i >= clearance && !IS_PASSABLE(grid.get(i-clearance, j), mask))
--numBlocked;
if (i+1+clearance < w && !IS_PASSABLE(grid.get(i+1+clearance, j), mask))
++numBlocked;
}
}
for (u16 i = 0; i < w; ++i)
{
// New cell (i,j) is blocked if (i,j') blocked for any j-clearance <= j' <= j+clearance
// Count the number of blocked cells around j=0
u16 numBlocked = 0;
for (u16 j = 0; j <= clearance && j < h; ++j)
if (tempGrid.get(i, j))
++numBlocked;
for (u16 j = 0; j < h; ++j)
{
// Add the mask if blocked by at least one nearby cell
if (numBlocked)
grid.set(i, j, grid.get(i, j) | mask);
// Slide the numBlocked window along:
// remove the old j-clearance value, add the new (j+1)+clearance
// (avoiding overflowing the grid)
if (j >= clearance && tempGrid.get(i, j-clearance))
--numBlocked;
if (j+1+clearance < h && tempGrid.get(i, j+1+clearance))
++numBlocked;
}
}
}
void GLL::GaussLobattoLegendreGridHomogenous(basics::Vector& grid)
{
basics::Vector tempGrid("temp",grid.length()+2);
GaussLobattoLegendreGrid(tempGrid);
grid = tempGrid[utilities::Range::colon(1,grid.length())];
}
void GLL::GaussLobattoLegendreGridPeriodic(basics::Vector& grid)
{
basics::Vector tempGrid("temp",grid.length()+1);
GaussLobattoLegendreGrid(tempGrid);
grid = tempGrid[utilities::Range::colon(0,grid.length()-1)];
}
