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Feature: Wide rivers

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pull/444/head
Tyler Trahan 3 years ago committed by Michael Lutz
parent 520520c11c
commit 664771d085
2 changed files with 185 additions and 10 deletions
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2
src/direction_type.h
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@ -102,10 +102,12 @@ template <> struct EnumPropsT<DiagDirection> : MakeEnumPropsT<DiagDirection, byt
* @see DirDiff
*/
enum DiagDirDiff {
DIAGDIRDIFF_BEGIN = 0, ///< Used for iterations
DIAGDIRDIFF_SAME = 0, ///< Same directions
DIAGDIRDIFF_90RIGHT = 1, ///< 90 degrees right
DIAGDIRDIFF_REVERSE = 2, ///< Reverse directions
DIAGDIRDIFF_90LEFT = 3, ///< 90 degrees left
DIAGDIRDIFF_END, ///< Used for iterations
};
/** Allow incrementing of DiagDirDiff variables */

193
src/landscape.cpp
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@ -32,6 +32,7 @@
#include "saveload/saveload.h"
#include "framerate_type.h"
#include "landscape_cmd.h"
#include "terraform_cmd.h"
#include "station_func.h"
#include <array>
#include <list>
@ -1071,6 +1072,128 @@ static bool MakeLake(TileIndex tile, void *user_data)
return false;
}
/**
* Widen a river by expanding into adjacent tiles via circular tile search.
* @param tile The tile to try expanding the river into.
* @param data The tile to try surrounding the river around.
* @return Always false, so it continues searching.
*/
static bool RiverMakeWider(TileIndex tile, void *data)
{
/* Don't expand into void tiles. */
if (!IsValidTile(tile)) return false;
/* If the tile is already sea or river, don't expand. */
if (IsWaterTile(tile)) return false;
/* If the tile is at height 0 after terraforming but the ocean hasn't flooded yet, don't build river. */
if (GetTileMaxZ(tile) == 0) return false;
TileIndex origin_tile = *(TileIndex *)data;;
Slope cur_slope = GetTileSlope(tile);
Slope desired_slope = GetTileSlope(origin_tile); // Initialize matching the origin tile as a shortcut if no terraforming is needed.
/* Never flow uphill. */
if (GetTileMaxZ(tile) > GetTileMaxZ(origin_tile)) return false;
/* If the new tile can't hold a river tile, try terraforming. */
if (!IsTileFlat(tile) && !IsInclinedSlope(cur_slope)) {
/* Don't try to terraform steep slopes. */
if (IsSteepSlope(cur_slope)) return false;
bool flat_river_found = false;
bool sloped_river_found = false;
/* There are two common possibilities:
* 1. River flat, adjacent tile has one corner lowered.
* 2. River descending, adjacent tile has either one or three corners raised.
*/
/* First, determine the desired slope based on adjacent river tiles. This doesn't necessarily match the origin tile for the CircularTileSearch. */
for (DiagDirection d = DIAGDIR_BEGIN; d < DIAGDIR_END; d++) {
TileIndex other_tile = TileAddByDiagDir(tile, d);
Slope other_slope = GetTileSlope(other_tile);
/* Only consider river tiles. */
if (IsWaterTile(other_tile) && IsRiver(other_tile)) {
/* If the adjacent river tile flows downhill, we need to check where we are relative to the slope. */
if (IsInclinedSlope(other_slope) && GetTileMaxZ(tile) == GetTileMaxZ(other_tile)) {
/* Check for a parallel slope. If we don't find one, we're above or below the slope instead. */
if (GetInclinedSlopeDirection(other_slope) == ChangeDiagDir(d, DIAGDIRDIFF_90RIGHT) ||
GetInclinedSlopeDirection(other_slope) == ChangeDiagDir(d, DIAGDIRDIFF_90LEFT)) {
desired_slope = other_slope;
sloped_river_found = true;
break;
}
}
/* If we find an adjacent river tile, remember it. We'll terraform to match it later if we don't find a slope. */
if (IsTileFlat(tile)) flat_river_found = true;
}
}
/* We didn't find either an inclined or flat river, so we're climbing the wrong slope. Bail out. */
if (!sloped_river_found && !flat_river_found) return false;
/* We didn't find an inclined river, but there is a flat river. */
if (!sloped_river_found && flat_river_found) desired_slope = SLOPE_FLAT;
/* Now that we know the desired slope, it's time to terraform! */
/* If the river is flat and the adjacent tile has one corner lowered, we want to raise it. */
if (desired_slope == SLOPE_FLAT && IsSlopeWithThreeCornersRaised(cur_slope)) {
/* Make sure we're not affecting an existing river slope tile. */
for (DiagDirection d = DIAGDIR_BEGIN; d < DIAGDIR_END; d++) {
TileIndex other_tile = TileAddByDiagDir(tile, d);
if (IsInclinedSlope(GetTileSlope(other_tile)) && IsWaterTile(other_tile)) return false;
}
Command<CMD_TERRAFORM_LAND>::Do(DC_EXEC | DC_AUTO, tile, ComplementSlope(cur_slope), true);
/* If the river is descending and the adjacent tile has either one or three corners raised, we want to make it match the slope. */
} else if (IsInclinedSlope(desired_slope)) {
/* Don't break existing flat river tiles by terraforming under them. */
DiagDirection river_direction = ReverseDiagDir(GetInclinedSlopeDirection(desired_slope));
for (DiagDirDiff d = DIAGDIRDIFF_BEGIN; d < DIAGDIRDIFF_END; d++) {
/* We don't care about downstream or upstream tiles, just the riverbanks. */
if (d == DIAGDIRDIFF_SAME || d == DIAGDIRDIFF_REVERSE) continue;
TileIndex other_tile = (TileAddByDiagDir(tile, ChangeDiagDir(river_direction, d)));
if (IsWaterTile(other_tile) && IsRiver(other_tile) && IsTileFlat(other_tile)) return false;
}
/* Get the corners which are different between the current and desired slope. */
Slope to_change = cur_slope ^ desired_slope;
/* Lower unwanted corners first. If only one corner is raised, no corners need lowering. */
if (!IsSlopeWithOneCornerRaised(cur_slope)) {
to_change = to_change & ComplementSlope(desired_slope);
Command<CMD_TERRAFORM_LAND>::Do(DC_EXEC | DC_AUTO, tile, to_change, false);
}
/* Now check the match and raise any corners needed. */
cur_slope = GetTileSlope(tile);
if (cur_slope != desired_slope && IsSlopeWithOneCornerRaised(cur_slope)) {
to_change = cur_slope ^ desired_slope;
Command<CMD_TERRAFORM_LAND>::Do(DC_EXEC | DC_AUTO, tile, to_change, true);
}
}
}
/* Update cur_slope after possibly terraforming. */
cur_slope = GetTileSlope(tile);
/* If the tile slope matches the desired slope, add a river tile. */
if (cur_slope == desired_slope) {
MakeRiver(tile, Random());
/* Remove desert directly around the river tile. */
TileIndex cur_tile = tile;
MarkTileDirtyByTile(cur_tile);
CircularTileSearch(&cur_tile, RIVER_OFFSET_DESERT_DISTANCE, RiverModifyDesertZone, nullptr);
}
/* Always return false to keep searching. */
return false;
}
/**
* Check whether a river at begin could (logically) flow down to end.
* @param begin The origin of the flow.
@ -1093,6 +1216,12 @@ static bool FlowsDown(TileIndex begin, TileIndex end)
((slopeEnd == slopeBegin && heightEnd < heightBegin) || slopeEnd == SLOPE_FLAT || slopeBegin == SLOPE_FLAT);
}
/** Parameters for river generation to pass as AyStar user data. */
struct River_UserData {
TileIndex spring; ///< The current spring during river generation.
bool main_river; ///< Whether the current river is a big river that others flow into.
};
/* AyStar callback for checking whether we reached our destination. */
static int32 River_EndNodeCheck(const AyStar *aystar, const OpenListNode *current)
{
@ -1130,7 +1259,11 @@ static void River_GetNeighbours(AyStar *aystar, OpenListNode *current)
/* AyStar callback when an route has been found. */
static void River_FoundEndNode(AyStar *aystar, OpenListNode *current)
{
for (PathNode *path = &current->path; path != nullptr; path = path->parent) {
River_UserData *data = (River_UserData *)aystar->user_data;
/* First, build the river without worrying about its width. */
uint cur_pos = 0;
for (PathNode *path = &current->path; path != nullptr; path = path->parent, cur_pos++) {
TileIndex tile = path->node.tile;
if (!IsWaterTile(tile)) {
MakeRiver(tile, Random());
@ -1139,6 +1272,24 @@ static void River_FoundEndNode(AyStar *aystar, OpenListNode *current)
CircularTileSearch(&tile, RIVER_OFFSET_DESERT_DISTANCE, RiverModifyDesertZone, nullptr);
}
}
/* If the river is a main river, go back along the path to widen it. */
if (data->main_river) {
const uint long_river_length = _settings_game.game_creation.min_river_length * 4;
uint current_river_length;
uint radius;
cur_pos = 0;
for (PathNode *path = &current->path; path != nullptr; path = path->parent, cur_pos++) {
TileIndex tile = path->node.tile;
/* Check if we should widen river depending on how far we are away from the source. */
current_river_length = DistanceManhattan(data->spring, tile);
radius = std::min(3u, (current_river_length / (long_river_length / 3u)) + 1u);
if (radius > 1) CircularTileSearch(&tile, radius + RandomRange(1), RiverMakeWider, (void *)&path->node.tile);
}
}
}
static const uint RIVER_HASH_SIZE = 8; ///< The number of bits the hash for river finding should have.
@ -1158,9 +1309,13 @@ static uint River_Hash(uint tile, uint dir)
* Actually build the river between the begin and end tiles using AyStar.
* @param begin The begin of the river.
* @param end The end of the river.
* @param spring The springing point of the river.
* @param main_river Whether the current river is a big river that others flow into.
*/
static void BuildRiver(TileIndex begin, TileIndex end)
static void BuildRiver(TileIndex begin, TileIndex end, TileIndex spring, bool main_river)
{
River_UserData user_data = { spring, main_river };
AyStar finder = {};
finder.CalculateG = River_CalculateG;
finder.CalculateH = River_CalculateH;
@ -1168,6 +1323,7 @@ static void BuildRiver(TileIndex begin, TileIndex end)
finder.EndNodeCheck = River_EndNodeCheck;
finder.FoundEndNode = River_FoundEndNode;
finder.user_target = &end;
finder.user_data = &user_data;
finder.Init(River_Hash, 1 << RIVER_HASH_SIZE);
@ -1183,15 +1339,19 @@ static void BuildRiver(TileIndex begin, TileIndex end)
* Try to flow the river down from a given begin.
* @param spring The springing point of the river.
* @param begin The begin point we are looking from; somewhere down hill from the spring.
* @return True iff a river could/has been built, otherwise false.
* @param min_river_length The minimum length for the river.
* @return First element: True iff a river could/has been built, otherwise false; second element: River ends at sea.
*/
static bool FlowRiver(TileIndex spring, TileIndex begin)
static std::tuple<bool, bool> FlowRiver(TileIndex spring, TileIndex begin, uint min_river_length)
{
# define SET_MARK(x) marks.insert(x)
# define IS_MARKED(x) (marks.find(x) != marks.end())
uint height = TileHeight(begin);
if (IsWaterTile(begin)) return DistanceManhattan(spring, begin) > _settings_game.game_creation.min_river_length;
if (IsWaterTile(begin)) {
return { DistanceManhattan(spring, begin) > min_river_length, GetTileZ(begin) == 0 };
}
std::set<TileIndex> marks;
SET_MARK(begin);
@ -1223,9 +1383,10 @@ static bool FlowRiver(TileIndex spring, TileIndex begin)
}
} while (!queue.empty());
bool main_river = false;
if (found) {
/* Flow further down hill. */
found = FlowRiver(spring, end);
std::tie(found, main_river) = FlowRiver(spring, end, min_river_length);
} else if (count > 32) {
/* Maybe we can make a lake. Find the Nth of the considered tiles. */
TileIndex lakeCenter = 0;
@ -1244,7 +1405,7 @@ static bool FlowRiver(TileIndex spring, TileIndex begin)
/* We don't want lakes in the desert. */
(_settings_game.game_creation.landscape != LT_TROPIC || GetTropicZone(lakeCenter) != TROPICZONE_DESERT) &&
/* We only want a lake if the river is long enough. */
DistanceManhattan(spring, lakeCenter) > _settings_game.game_creation.min_river_length) {
DistanceManhattan(spring, lakeCenter) > min_river_length) {
end = lakeCenter;
MakeRiver(lakeCenter, Random());
MarkTileDirtyByTile(lakeCenter);
@ -1261,8 +1422,8 @@ static bool FlowRiver(TileIndex spring, TileIndex begin)
}
marks.clear();
if (found) BuildRiver(begin, end);
return found;
if (found) BuildRiver(begin, end, spring, main_river);
return { found, main_river };
}
/**
@ -1274,14 +1435,26 @@ static void CreateRivers()
if (amount == 0) return;
uint wells = ScaleByMapSize(4 << _settings_game.game_creation.amount_of_rivers);
const uint num_short_rivers = wells - std::max(1u, wells / 10);
SetGeneratingWorldProgress(GWP_RIVER, wells + 256 / 64); // Include the tile loop calls below.
/* Try to create long rivers. */
for (; wells > num_short_rivers; wells--) {
IncreaseGeneratingWorldProgress(GWP_RIVER);
for (int tries = 0; tries < 512; tries++) {
TileIndex t = RandomTile();
if (!CircularTileSearch(&t, 8, FindSpring, nullptr)) continue;
if (std::get<0>(FlowRiver(t, t, _settings_game.game_creation.min_river_length * 4))) break;
}
}
/* Try to create short rivers. */
for (; wells != 0; wells--) {
IncreaseGeneratingWorldProgress(GWP_RIVER);
for (int tries = 0; tries < 128; tries++) {
TileIndex t = RandomTile();
if (!CircularTileSearch(&t, 8, FindSpring, nullptr)) continue;
if (FlowRiver(t, t)) break;
if (std::get<0>(FlowRiver(t, t, _settings_game.game_creation.min_river_length))) break;
}
}

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