std::list<BlockingObject> World::LoS(const position &startingpos, const position &endingpos) const {
std::list<BlockingObject> ret;
ret.clear();
bool steep = std::abs(startingpos.y - endingpos.y) > std::abs(startingpos.x - endingpos.x);
short int startx=startingpos.x;
short int starty=startingpos.y;
short int endx=endingpos.x;
short int endy=endingpos.y;
if (steep) {
//change x,y values for correct algorithm in negativ range
short int change;
change = startx;
startx = starty;
starty = change;
change = endx;
endx = endy;
endy = change;
}
bool swapped = startx > endx;
if (swapped) {
short int change;
change = startx;
startx = endx;
endx = change;
change = starty;
starty = endy;
endy = change;
}
short int deltax = endx - startx;
short int deltay = std::abs(endy - starty);
short int error = 0;
short int ystep=1;
short int y = starty;
if (starty > endy) {
ystep = -1;
}
for (short int x = startx; x <= endx; ++x) {
if (!(x == startx && y == starty) && !(x == endx && y == endy)) {
BlockingObject bo;
Field *temp;
position pos{x, y, startingpos.z};
if (steep) {
pos.x = y;
pos.y = x;
}
if (GetPToCFieldAt(temp, pos)) {
if (temp->IsPlayerOnField()) {
bo.blockingType = BlockingObject::BT_CHARACTER;
bo.blockingChar = findCharacterOnField(pos);
if (swapped) {
ret.push_back(bo);
} else {
ret.push_front(bo);
}
} else {
ScriptItem it;
for (size_t i = 0; i < temp->NumberOfItems(); ++i) {
auto testItem = temp->getStackItem(i);
if (testItem.getVolume() > it.getVolume()) {
it = testItem;
}
}
if (it.isLarge()) {
bo.blockingType = BlockingObject::BT_ITEM;
it.pos = pos;
it.type = ScriptItem::it_field;
bo.blockingItem = it;
if (swapped) {
ret.push_back(bo);
} else {
ret.push_front(bo);
}
}
}
}
}
error += deltay;
if (2*error >= deltax) {
y+=ystep;
error -= deltax;
}
}
return ret;
}
