Method RebuildCache

src/linkgraph/linkgraph_gui.cpp:71–119

* Rebuild the cache and recalculate which links and stations to be shown. */

 * Rebuild the cache and recalculate which links and stations to be shown.
 */
void LinkGraphOverlay::RebuildCache()
{
	this->cached_links.clear();
	this->cached_stations.clear();
	if (this->company_mask.None()) return;

	DrawPixelInfo dpi;
	this->GetWidgetDpi(&dpi);

	for (const Station *sta : Station::Iterate()) {
		if (sta->rect.IsEmpty()) continue;

		Point pta = this->GetStationMiddle(sta);

		StationID from = sta->index;
		StationLinkMap &seen_links = this->cached_links[from];

		uint supply = 0;
		for (CargoType cargo : SetCargoBitIterator(this->cargo_mask)) {
			if (!CargoSpec::Get(cargo)->IsValid()) continue;
			if (!LinkGraph::IsValidID(sta->goods[cargo].link_graph)) continue;
			const LinkGraph &lg = *LinkGraph::Get(sta->goods[cargo].link_graph);

			ConstNode &from_node = lg[sta->goods[cargo].node];
			supply += lg.Monthly(from_node.supply);
			for (const Edge &edge : from_node.edges) {
				StationID to = lg[edge.dest_node].station;
				assert(from != to);
				if (!Station::IsValidID(to) || seen_links.find(to) != seen_links.end()) {
					continue;
				}
				const Station *stb = Station::Get(to);
				assert(sta != stb);

				/* Show links between stations of selected companies or "neutral" ones like oilrigs. */
				if (stb->owner != OWNER_NONE && sta->owner != OWNER_NONE && !this->company_mask.Test(stb->owner)) continue;
				if (stb->rect.IsEmpty()) continue;

				if (!this->IsLinkVisible(pta, this->GetStationMiddle(stb), &dpi)) continue;

				this->AddLinks(sta, stb);
				seen_links[to]; // make sure it is created and marked as seen
			}
		}
		if (this->IsPointVisible(pta, &dpi)) {
			this->cached_stations.emplace_back(from, supply);
		}
	}
}

/**
 * Determine if a certain point is inside the given DPI, with some lee way.