landscape.cpp

	const TileIndexDiffC *data;
	update_freq = normal_tiles.size() / 5;
	auto tile_count = 0, gwp = 0;
	for (auto &tile : normal_tiles) {
		tile_count++;
		if (gwp == 0 || tile_count == update_freq && gwp < 5) {
			IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
			if (gwp != 0) tile_count = 0;
			gwp++;
		}