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Code Issues Releases Wiki Activity

Change: Ensure generated towns have enough room (#14803)

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This commit is contained in:
Tyler Trahan
2025-11-25 05:39:17 -05:00
committed by GitHub
parent 5bd28fa692
commit b4ac5e2231
1 changed files with 32 additions and 8 deletions
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40
src/town_cmd.cpp
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@@ -55,6 +55,8 @@
#include "road_cmd.h"
#include "terraform_cmd.h"
#include "tunnelbridge_cmd.h"
#include "clear_map.h"
#include "tree_map.h"
#include "map_func.h"
#include "timer/timer.h"
#include "timer/timer_game_calendar.h"
@@ -2113,9 +2115,10 @@ static void DoCreateTown(Town *t, TileIndex tile, uint32_t townnameparts, TownSi
/**
* Check if it's possible to place a town on a given tile.
* @param tile The tile to check.
* @param check_surrounding Should we ensure surrounding tiles are free too?
* @return A zero cost if allowed, otherwise an error.
*/
static CommandCost TownCanBePlacedHere(TileIndex tile)
static CommandCost TownCanBePlacedHere(TileIndex tile, bool check_surrounding)
{
/* Check if too close to the edge of map */
if (DistanceFromEdge(tile) < 12) {
@@ -2132,6 +2135,29 @@ static CommandCost TownCanBePlacedHere(TileIndex tile)
return CommandCost(STR_ERROR_SITE_UNSUITABLE);
}
/* We might want to make sure the town has enough room. */
if (check_surrounding) {
constexpr uint SEARCH_DIAMETER = 5; // Center tile of town + 2 tile radius.
/* Half of the tiles in the search must be valid for the town to build upon. */
constexpr uint VALID_TILE_GOAL = (SEARCH_DIAMETER * SEARCH_DIAMETER) / 2;
uint counter = 0;
for (TileIndex t : SpiralTileSequence(tile, SEARCH_DIAMETER)) {
if (counter == VALID_TILE_GOAL) break;
/* The most likely unsuitable tile type is water, test that first. */
if (IsTileType(tile, MP_WATER)) continue;
/* Don't allow rough tiles, as they are likely wetlands. */
bool clear = IsTileType(t, MP_CLEAR) && GetClearDensity(t) != CLEAR_ROUGH;
bool trees = IsTileType(t, MP_TREES) && GetTreeGround(t) != TREE_GROUND_ROUGH;
int town_height = GetTileZ(tile);
bool elevation_similar = (GetTileMaxZ(t) <= town_height + 1) && (GetTileZ(t) >= town_height - 1);
if ((clear || trees) && elevation_similar) counter++;
}
if (counter < VALID_TILE_GOAL) return CommandCost(STR_ERROR_SITE_UNSUITABLE);
}
return CommandCost(EXPENSES_OTHER);
}
@@ -2194,7 +2220,7 @@ std::tuple<CommandCost, Money, TownID> CmdFoundTown(DoCommandFlags flags, TileIn
if (!Town::CanAllocateItem()) return { CommandCost(STR_ERROR_TOO_MANY_TOWNS), 0, TownID::Invalid() };
if (!random_location) {
CommandCost ret = TownCanBePlacedHere(tile);
CommandCost ret = TownCanBePlacedHere(tile, false);
if (ret.Failed()) return { ret, 0, TownID::Invalid() };
}
@@ -2311,6 +2337,7 @@ static TileIndex FindNearestGoodCoastalTownSpot(TileIndex tile, TownLayout layou
uint max_dist = 0;
for (auto test : SpiralTileSequence(coast, 10)) {
if (!IsTileType(test, MP_CLEAR) || !IsTileFlat(test) || !IsTileAlignedToGrid(test, layout)) continue;
if (TownCanBePlacedHere(tile, true).Failed()) continue;
uint dist = GetClosestWaterDistance(test, true);
if (dist > max_dist) {
@@ -2359,15 +2386,12 @@ static Town *CreateRandomTown(uint attempts, uint32_t townnameparts, TownSize si
/* Generate a tile index not too close from the edge */
TileIndex tile = AlignTileToGrid(RandomTile(), layout);
/* if we tried to place the town on water, slide it over onto
* the nearest likely-looking spot */
/* If we tried to place the town on water, find a suitable land tile nearby.
* Otherwise, evaluate the land tile. */
if (IsTileType(tile, MP_WATER)) {
tile = FindNearestGoodCoastalTownSpot(tile, layout);
if (tile == INVALID_TILE) continue;
}
/* Make sure town can be placed here */
if (TownCanBePlacedHere(tile).Failed()) continue;
} else if (TownCanBePlacedHere(tile, true).Failed()) continue;
/* Allocate a town struct */
Town *t = new Town(tile);