void calculateDistances(short **distanceMap,
short destinationX, short destinationY,
unsigned long blockingTerrainFlags,
creature *traveler,
boolean canUseSecretDoors,
boolean eightWays) {
creature *monst;
static pdsMap map;
short i, j;
for (i=0; i<DCOLS; i++) {
for (j=0; j<DROWS; j++) {
char cost;
monst = monsterAtLoc(i, j);
if (monst
&& (monst->info.flags & (MONST_IMMUNE_TO_WEAPONS | MONST_INVULNERABLE))
&& (monst->info.flags & (MONST_IMMOBILE | MONST_GETS_TURN_ON_ACTIVATION))) {
// Always avoid damage-immune stationary monsters.
cost = PDS_FORBIDDEN;
} else if (canUseSecretDoors
&& cellHasTMFlag(i, j, TM_IS_SECRET)
&& cellHasTerrainFlag(i, j, T_OBSTRUCTS_PASSABILITY)
&& !(discoveredTerrainFlagsAtLoc(i, j) & T_OBSTRUCTS_PASSABILITY)) {
cost = 1;
} else if (cellHasTerrainFlag(i, j, T_OBSTRUCTS_PASSABILITY)
|| (traveler && traveler == &player && !(pmap[i][j].flags & (DISCOVERED | MAGIC_MAPPED)))) {
cost = cellHasTerrainFlag(i, j, T_OBSTRUCTS_DIAGONAL_MOVEMENT) ? PDS_OBSTRUCTION : PDS_FORBIDDEN;
} else if ((traveler && monsterAvoids(traveler, i, j)) || cellHasTerrainFlag(i, j, blockingTerrainFlags)) {
cost = PDS_FORBIDDEN;
} else {
cost = 1;
}
PDS_CELL(&map, i, j)->cost = cost;
}
}
pdsClear(&map, 30000, eightWays);
pdsSetDistance(&map, destinationX, destinationY, 0);
pdsBatchOutput(&map, distanceMap);
}
// Fills grid locations with the given value if they match any terrain flags or map flags.
// Otherwise does not change the grid location.
void getTerrainGrid(short **grid, short value, unsigned long terrainFlags, unsigned long mapFlags) {
short i, j;
for(i = 0; i < DCOLS; i++) {
for(j = 0; j < DROWS; j++) {
if (grid[i][j] != value && cellHasTerrainFlag(i, j, terrainFlags) || (pmap[i][j].flags & mapFlags)) {
grid[i][j] = value;
}
}
}
}
// This is a custom implementation of recursive shadowcasting.
void scanOctantFOV(char grid[VIEWWIDTH][VIEWHEIGHT], short xLoc, short yLoc, short octant, float maxRadius,
short columnsRightFromOrigin, long startSlope, long endSlope, unsigned long forbiddenTerrain,
unsigned long forbiddenFlags, boolean cautiousOnWalls) {
if (columnsRightFromOrigin >= maxRadius) return;
short i, a, b, iStart, iEnd, x, y, x2, y2; // x and y are temporary variables on which we do the octant transform
long newStartSlope, newEndSlope;
boolean cellObstructed;
newStartSlope = startSlope;
a = ((LOS_SLOPE_GRANULARITY / -2 + 1) + startSlope * columnsRightFromOrigin) / LOS_SLOPE_GRANULARITY;
b = ((LOS_SLOPE_GRANULARITY / -2 + 1) + endSlope * columnsRightFromOrigin) / LOS_SLOPE_GRANULARITY;
iStart = min(a, b);
iEnd = max(a, b);
// restrict vision to a circle of radius maxRadius
if ((columnsRightFromOrigin*columnsRightFromOrigin + iEnd*iEnd) >= maxRadius*maxRadius) {
return;
}
if ((columnsRightFromOrigin*columnsRightFromOrigin + iStart*iStart) >= maxRadius*maxRadius) {
iStart = (int) (-1 * sqrt(maxRadius*maxRadius - columnsRightFromOrigin*columnsRightFromOrigin) + FLOAT_FUDGE);
}
x = xLoc + columnsRightFromOrigin;
y = yLoc + iStart;
betweenOctant1andN(&x, &y, xLoc, yLoc, octant);
boolean currentlyLit = coordinatesAreInMap(x, y) && !(cellHasTerrainFlag(x, y, forbiddenTerrain) ||
(pmap[x][y].flags & forbiddenFlags));
for (i = iStart; i <= iEnd; i++) {
x = xLoc + columnsRightFromOrigin;
y = yLoc + i;
betweenOctant1andN(&x, &y, xLoc, yLoc, octant);
if (!coordinatesAreInMap(x, y)) {
// We're off the map -- here there be memory corruption.
continue;
}
cellObstructed = (cellHasTerrainFlag(x, y, forbiddenTerrain) || (pmap[x][y].flags & forbiddenFlags));
// if we're cautious on walls and this is a wall:
if (cautiousOnWalls && cellObstructed) {
// (x2, y2) is the tile one space closer to the origin from the tile we're on:
x2 = xLoc + columnsRightFromOrigin - 1;
y2 = yLoc + i;
if (i < 0) {
y2++;
} else if (i > 0) {
y2--;
}
betweenOctant1andN(&x2, &y2, xLoc, yLoc, octant);
if (pmap[x2][y2].flags & IN_FIELD_OF_VIEW) {
// previous tile is visible, so illuminate
grid[x][y] = 1;
}
} else {
// illuminate
grid[x][y] = 1;
}
if (!cellObstructed && !currentlyLit) { // next column slope starts here
newStartSlope = (long int) ((LOS_SLOPE_GRANULARITY * (i) - LOS_SLOPE_GRANULARITY / 2) / (columnsRightFromOrigin + 0.5));
currentlyLit = true;
} else if (cellObstructed && currentlyLit) { // next column slope ends here
newEndSlope = (long int) ((LOS_SLOPE_GRANULARITY * (i) - LOS_SLOPE_GRANULARITY / 2)
/ (columnsRightFromOrigin - 0.5));
if (newStartSlope <= newEndSlope) {
// run next column
scanOctantFOV(grid, xLoc, yLoc, octant, maxRadius, columnsRightFromOrigin + 1, newStartSlope, newEndSlope,
forbiddenTerrain, forbiddenFlags, cautiousOnWalls);
}
currentlyLit = false;
}
}
if (currentlyLit) { // got to the bottom of the scan while lit
newEndSlope = endSlope;
if (newStartSlope <= newEndSlope) {
// run next column
scanOctantFOV(grid, xLoc, yLoc, octant, maxRadius, columnsRightFromOrigin + 1, newStartSlope, newEndSlope,
forbiddenTerrain, forbiddenFlags, cautiousOnWalls);
}
}
}
boolean getQualifyingPathLocNear(short *retValX, short *retValY,
short x, short y,
boolean hallwaysAllowed,
unsigned long blockingTerrainFlags,
unsigned long blockingMapFlags,
unsigned long forbiddenTerrainFlags,
unsigned long forbiddenMapFlags,
boolean deterministic) {
short **grid, **costMap;
short loc[2];
// First check the given location to see if it works, as an optimization.
if (!cellHasTerrainFlag(x, y, blockingTerrainFlags | forbiddenTerrainFlags)
&& !(pmap[x][y].flags & (blockingMapFlags | forbiddenMapFlags))
&& (hallwaysAllowed || passableArcCount(x, y) <= 1)) {
*retValX = x;
*retValY = y;
return true;
}
// Allocate the grids.
grid = allocGrid();
costMap = allocGrid();
// Start with a base of a high number everywhere.
fillGrid(grid, 30000);
fillGrid(costMap, 1);
// Block off the pathing blockers.
getTerrainGrid(costMap, PDS_FORBIDDEN, blockingTerrainFlags, blockingMapFlags);
if (blockingTerrainFlags & (T_OBSTRUCTS_DIAGONAL_MOVEMENT | T_OBSTRUCTS_PASSABILITY)) {
getTerrainGrid(costMap, PDS_OBSTRUCTION, T_OBSTRUCTS_DIAGONAL_MOVEMENT, 0);
}
// Run the distance scan.
grid[x][y] = 1;
costMap[x][y] = 1;
dijkstraScan(grid, costMap, true);
findReplaceGrid(grid, 30000, 30000, 0);
// Block off invalid targets that aren't pathing blockers.
getTerrainGrid(grid, 0, forbiddenTerrainFlags, forbiddenMapFlags);
if (!hallwaysAllowed) {
getPassableArcGrid(grid, 2, 10, 0);
}
// Get the solution.
randomLeastPositiveLocationInGrid(grid, retValX, retValY, deterministic);
// dumpLevelToScreen();
// displayGrid(grid);
// if (coordinatesAreInMap(*retValX, *retValY)) {
// hiliteCell(*retValX, *retValY, &yellow, 100, true);
// }
// temporaryMessage("Qualifying path selected:", true);
freeGrid(grid);
freeGrid(costMap);
// Fall back to a pathing-agnostic alternative if there are no solutions.
if (*retValX == -1 && *retValY == -1) {
if (getQualifyingLocNear(loc, x, y, hallwaysAllowed, NULL,
(blockingTerrainFlags | forbiddenTerrainFlags),
(blockingMapFlags | forbiddenMapFlags),
false, deterministic)) {
*retValX = loc[0];
*retValY = loc[1];
return true; // Found a fallback solution.
} else {
return false; // No solutions.
}
} else {
return true; // Found a primary solution.
}
}
void pdsBatchInput(pdsMap *map, short **distanceMap, short **costMap, short maxDistance, boolean eightWays) {
short i, j;
pdsLink *left, *right;
map->eightWays = eightWays;
left = NULL;
right = NULL;
map->front.right = NULL;
for (i=0; i<DCOLS; i++) {
for (j=0; j<DROWS; j++) {
pdsLink *link = PDS_CELL(map, i, j);
if (distanceMap != NULL) {
link->distance = distanceMap[i][j];
} else {
if (costMap != NULL) {
// totally hackish; refactor
link->distance = maxDistance;
}
}
int cost;
if (i == 0 || j == 0 || i == DCOLS - 1 || j == DROWS - 1) {
cost = PDS_OBSTRUCTION;
} else if (costMap == NULL) {
if (cellHasTerrainFlag(i, j, T_OBSTRUCTS_PASSABILITY) && cellHasTerrainFlag(i, j, T_OBSTRUCTS_DIAGONAL_MOVEMENT)) cost = PDS_OBSTRUCTION;
else cost = PDS_FORBIDDEN;
} else {
cost = costMap[i][j];
}
link->cost = cost;
if (cost > 0) {
if (link->distance < maxDistance) {
if (right == NULL || right->distance > link->distance) {
// left and right are used to traverse the list; if many cells have similar values,
// some time can be saved by not clearing them with each insertion. this time,
// sadly, we have to start from the front.
left = &map->front;
right = map->front.right;
}
while (right != NULL && right->distance < link->distance) {
left = right;
right = right->right;
}
link->right = right;
link->left = left;
left->right = link;
if (right != NULL) right->left = link;
left = link;
} else {
link->right = NULL;
link->left = NULL;
}
} else {
link->right = NULL;
link->left = NULL;
}
}
}
}