(svn r22767) -Add: river generation
This commit is contained in:
rubidium
@@ -32,6 +32,8 @@
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#include "water_map.h"
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#include "economy_func.h"
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#include "company_func.h"
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#include "pathfinder/npf/aystar.h"
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#include <list>
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#include "table/strings.h"
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#include "table/sprites.h"
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@@ -916,6 +918,268 @@ static void CreateDesertOrRainForest()
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}
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}
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/**
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* Find the spring of a river.
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* @param tile The tile to consider for being the spring.
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* @param user_data Ignored data.
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* @return True iff it is suitable as a spring.
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*/
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static bool FindSpring(TileIndex tile, void *user_data)
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{
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uint referenceHeight;
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Slope s = GetTileSlope(tile, &referenceHeight);
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if (s != SLOPE_FLAT || IsWaterTile(tile)) return false;
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/* In the tropics rivers start in the rainforest. */
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if (_settings_game.game_creation.landscape == LT_TROPIC && GetTropicZone(tile) != TROPICZONE_RAINFOREST) return false;
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/* Are there enough higher tiles to warrant a 'spring'? */
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uint num = 0;
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for (int dx = -1; dx <= 1; dx++) {
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for (int dy = -1; dy <= 1; dy++) {
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TileIndex t = TileAddWrap(tile, dx, dy);
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if (t != INVALID_TILE && GetTileMaxZ(t) > referenceHeight) num++;
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}
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}
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if (num < 4) return false;
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/* Are we near the top of a hill? */
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for (int dx = -16; dx <= 16; dx++) {
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for (int dy = -16; dy <= 16; dy++) {
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TileIndex t = TileAddWrap(tile, dx, dy);
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if (t != INVALID_TILE && GetTileMaxZ(t) > referenceHeight + 2 * TILE_HEIGHT) return false;
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}
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}
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return true;
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}
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/**
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* Make a connected lake; fill all tiles in the circular tile search that are connected.
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* @param tile The tile to consider for lake making.
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* @param user_data The height of the lake.
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* @return Always false, so it continues searching.
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*/
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static bool MakeLake(TileIndex tile, void *user_data)
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{
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uint height = *(uint*)user_data;
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if (!IsValidTile(tile) || TileHeight(tile) != height || GetTileSlope(tile, NULL) != SLOPE_FLAT) return false;
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if (_settings_game.game_creation.landscape == LT_TROPIC && GetTropicZone(tile) == TROPICZONE_DESERT) return false;
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for (DiagDirection d = DIAGDIR_BEGIN; d < DIAGDIR_END; d++) {
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TileIndex t2 = tile + TileOffsByDiagDir(d);
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if (IsWaterTile(t2)) {
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MakeRiver(tile, Random());
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return false;
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}
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}
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return false;
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}
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/**
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* Check whether a river at begin could (logically) flow down to end.
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* @param begin The origin of the flow.
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* @param end The destination of the flow.
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* @return True iff the water can be flowing down.
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*/
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static bool FlowsDown(TileIndex begin, TileIndex end)
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{
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assert(DistanceManhattan(begin, end) == 1);
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uint heightBegin;
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uint heightEnd;
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Slope slopeBegin = GetTileSlope(begin, &heightBegin);
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Slope slopeEnd = GetTileSlope(end, &heightEnd);
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return heightEnd <= heightBegin &&
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/* Slope either is inclined or flat; rivers don't support other slopes. */
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(slopeEnd == SLOPE_FLAT || IsInclinedSlope(slopeEnd)) &&
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/* Slope continues, then it must be lower... or either end must be flat. */
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((slopeEnd == slopeBegin && heightEnd < heightBegin) || slopeEnd == SLOPE_FLAT || slopeBegin == SLOPE_FLAT);
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}
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/* AyStar callback for checking whether we reached our destination. */
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static int32 River_EndNodeCheck(AyStar *aystar, OpenListNode *current)
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{
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return current->path.node.tile == *(TileIndex*)aystar->user_target ? AYSTAR_FOUND_END_NODE : AYSTAR_DONE;
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}
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/* AyStar callback for getting the cost of the current node. */
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static int32 River_CalculateG(AyStar *aystar, AyStarNode *current, OpenListNode *parent)
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{
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return 1 + RandomRange(_settings_game.game_creation.river_route_random);
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}
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/* AyStar callback for getting the estimated cost to the destination. */
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static int32 River_CalculateH(AyStar *aystar, AyStarNode *current, OpenListNode *parent)
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{
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return DistanceManhattan(*(TileIndex*)aystar->user_target, current->tile);
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}
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/* AyStar callback for getting the neighbouring nodes of the given node. */
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static void River_GetNeighbours(AyStar *aystar, OpenListNode *current)
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{
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TileIndex tile = current->path.node.tile;
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aystar->num_neighbours = 0;
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for (DiagDirection d = DIAGDIR_BEGIN; d < DIAGDIR_END; d++) {
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TileIndex t2 = tile + TileOffsByDiagDir(d);
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if (IsValidTile(t2) && FlowsDown(tile, t2)) {
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aystar->neighbours[aystar->num_neighbours].tile = t2;
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aystar->neighbours[aystar->num_neighbours].direction = INVALID_TRACKDIR;
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aystar->num_neighbours++;
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}
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}
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}
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/* AyStar callback when an route has been found. */
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static void River_FoundEndNode(AyStar *aystar, OpenListNode *current)
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{
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for (PathNode *path = ¤t->path; path != NULL; path = path->parent) {
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if (!IsWaterTile(path->node.tile)) MakeRiver(path->node.tile, Random());
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}
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}
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static const uint RIVER_HASH_SIZE = 8; ///< The number of bits the hash for river finding should have.
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/**
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* Simple hash function for river tiles to be used by AyStar.
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* @param tile The tile to hash.
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* @param dir The unused direction.
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* @return The hash for the tile.
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*/
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static uint River_Hash(uint tile, uint dir)
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{
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return GB(TileHash(TileX(tile), TileY(tile)), 0, RIVER_HASH_SIZE);
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}
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/**
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* Actually build the river between the begin and end tiles using AyStar.
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* @param begin The begin of the river.
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* @param end The end of the river.
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*/
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static void BuildRiver(TileIndex begin, TileIndex end)
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{
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AyStar finder;
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MemSetT(&finder, 0);
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finder.CalculateG = River_CalculateG;
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finder.CalculateH = River_CalculateH;
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finder.GetNeighbours = River_GetNeighbours;
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finder.EndNodeCheck = River_EndNodeCheck;
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finder.FoundEndNode = River_FoundEndNode;
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finder.user_target = &end;
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finder.Init(River_Hash, 1 << RIVER_HASH_SIZE);
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AyStarNode start;
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start.tile = begin;
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start.direction = INVALID_TRACKDIR;
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finder.AddStartNode(&start, 0);
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finder.Main();
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finder.Free();
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}
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/**
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* Try to flow the river down from a given begin.
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* @param marks Array for temporary of iterated tiles.
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* @param spring The springing point of the river.
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* @param begin The begin point we are looking from; somewhere down hill from the spring.
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* @return True iff a river could/has been built, otherwise false.
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*/
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static bool FlowRiver(bool *marks, TileIndex spring, TileIndex begin)
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{
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uint height = TileHeight(begin);
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if (IsWaterTile(begin)) return DistanceManhattan(spring, begin) > _settings_game.game_creation.min_river_length;
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MemSetT(marks, 0, MapSize());
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marks[begin] = true;
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/* Breadth first search for the closest tile we can flow down to. */
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std::list<TileIndex> queue;
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queue.push_back(begin);
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bool found = false;
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uint count = 0; // Number of tiles considered; to be used for lake location guessing.
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TileIndex end;
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do {
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end = queue.front();
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queue.pop_front();
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uint height2 = TileHeight(end);
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if (GetTileSlope(end, NULL) == SLOPE_FLAT && (height2 < height || (height2 == height && IsWaterTile(end)))) {
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found = true;
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break;
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}
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for (DiagDirection d = DIAGDIR_BEGIN; d < DIAGDIR_END; d++) {
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TileIndex t2 = end + TileOffsByDiagDir(d);
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if (IsValidTile(t2) && !marks[t2] && FlowsDown(end, t2)) {
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marks[t2] = true;
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count++;
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queue.push_back(t2);
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}
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}
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} while (!queue.empty());
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if (found) {
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/* Flow further down hill. */
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found = FlowRiver(marks, spring, end);
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} else if (count > 10) {
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/* Maybe we can make a lake. Find the Nth of the considered tiles. */
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TileIndex lakeCenter = 0;
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for (int i = RandomRange(count - 1); i != 0; lakeCenter++) {
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if (marks[lakeCenter]) i--;
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}
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if (IsValidTile(lakeCenter) &&
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/* A river, or lake, can only be built on flat slopes. */
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GetTileSlope(lakeCenter, NULL) == SLOPE_FLAT &&
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/* We want the lake to be built at the height of the river. */
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TileHeight(begin) == TileHeight(lakeCenter) &&
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/* We don't want the lake at the entry of the valley. */
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lakeCenter != begin &&
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/* We don't want lakes in the desert. */
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(_settings_game.game_creation.landscape != LT_TROPIC || GetTropicZone(lakeCenter) != TROPICZONE_DESERT) &&
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/* We only want a lake if the river is long enough. */
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DistanceManhattan(spring, lakeCenter) > _settings_game.game_creation.min_river_length) {
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end = lakeCenter;
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MakeRiver(lakeCenter, Random());
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uint range = RandomRange(8) + 3;
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CircularTileSearch(&lakeCenter, range, MakeLake, &height);
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/* Call the search a second time so artefacts from going circular in one direction get (mostly) hidden. */
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lakeCenter = end;
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CircularTileSearch(&lakeCenter, range, MakeLake, &height);
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found = true;
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}
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}
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if (found) BuildRiver(begin, end);
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return found;
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}
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/**
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* Actually (try to) create some rivers.
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*/
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static void CreateRivers()
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{
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int amount = _settings_game.game_creation.amount_of_rivers;
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if (amount == 0) return;
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bool *marks = CallocT<bool>(MapSize());
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for (uint wells = ScaleByMapSize(4 << _settings_game.game_creation.amount_of_rivers); wells != 0; wells--) {
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for (int tries = 0; tries < 128; tries++) {
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TileIndex t = RandomTile();
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if (!CircularTileSearch(&t, 8, FindSpring, NULL)) continue;
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if (FlowRiver(marks, t, t)) break;
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}
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}
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free(marks);
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}
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void GenerateLandscape(byte mode)
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{
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/** Number of steps of landscape generation */
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@@ -997,6 +1261,8 @@ void GenerateLandscape(byte mode)
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IncreaseGeneratingWorldProgress(GWP_LANDSCAPE);
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if (_settings_game.game_creation.landscape == LT_TROPIC) CreateDesertOrRainForest();
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CreateRivers();
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}
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void OnTick_Town();
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