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Use fractal noise for more natural tree placement

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This commit is contained in:
Hielke Morsink
2022-04-14 23:12:50 +02:00
parent e2af1588ff
commit 1b79f505b6
1 changed files with 37 additions and 64 deletions
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101
src/openrct2/world/MapGen.cpp
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@@ -95,6 +95,7 @@ static void mapgen_set_water_level(int32_t waterLevel);
static void mapgen_smooth_height(int32_t iterations);
static void mapgen_set_height();
static float fractal_noise(int32_t x, int32_t y, float frequency, int32_t octaves, float lacunarity, float persistence);
static void mapgen_simplex(mapgen_settings* settings);
static int32_t _heightSize;
@@ -315,82 +316,54 @@ static void mapgen_place_trees()
}
}
TileCoordsXY tmp, pos;
std::vector<TileCoordsXY> availablePositions;
// Create list of available tiles
// Place trees
CoordsXY pos;
float treeToLandRatio = (10 + (util_rand() % 30)) / 100.0f;
for (int32_t y = 1; y < gMapSize.y - 1; y++)
{
for (int32_t x = 1; x < gMapSize.x - 1; x++)
{
auto* surfaceElement = map_get_surface_element_at(TileCoordsXY{ x, y }.ToCoordsXY());
pos.x = x * COORDS_XY_STEP;
pos.y = y * COORDS_XY_STEP;
auto* surfaceElement = map_get_surface_element_at(pos);
if (surfaceElement == nullptr)
continue;
// Exclude water tiles
// Don't place on water
if (surfaceElement->GetWaterHeight() > 0)
continue;
pos.x = x;
pos.y = y;
availablePositions.push_back(pos);
if (static_cast<float>(util_rand()) / 0xFFFFFFFF > treeToLandRatio)
continue;
// Use fractal noise to group tiles that are likely to spawn trees together
float noiseValue = std::clamp(fractal_noise(x, y, 0.025f, 8, 2.0f, 0.65f), -1.0f, 1.0f);
if (noiseValue < 0.0f)
continue;
ObjectEntryIndex treeObjectEntryIndex = OBJECT_ENTRY_INDEX_NULL;
const auto& surfaceStyleObject = *TerrainSurfaceObject::GetById(surfaceElement->GetSurfaceStyle());
if (MapGenSurfaceTakesGrassTrees(surfaceStyleObject))
{
if (!grassTreeIds.empty())
treeObjectEntryIndex = grassTreeIds[util_rand() % grassTreeIds.size()];
}
else if (MapGenSurfaceTakesSandTrees(surfaceStyleObject))
{
if (!desertTreeIds.empty() && util_rand() % 4 == 0)
treeObjectEntryIndex = desertTreeIds[util_rand() % desertTreeIds.size()];
}
else if (MapGenSurfaceTakesSnowTrees(surfaceStyleObject))
{
if (!snowTreeIds.empty())
treeObjectEntryIndex = snowTreeIds[util_rand() % snowTreeIds.size()];
}
if (treeObjectEntryIndex != OBJECT_ENTRY_INDEX_NULL)
mapgen_place_tree(treeObjectEntryIndex, pos);
}
}
// Shuffle list
for (uint32_t i = 0; i < availablePositions.size(); i++)
{
uint32_t rindex = util_rand() % availablePositions.size();
if (rindex == i)
continue;
tmp = availablePositions[i];
availablePositions[i] = availablePositions[rindex];
availablePositions[rindex] = tmp;
}
// Place trees
float treeToLandRatio = (10 + (util_rand() % 30)) / 100.0f;
int32_t numTrees = std::min(
std::max(4, static_cast<int32_t>(availablePositions.size() * treeToLandRatio)),
static_cast<int32_t>(availablePositions.size()));
for (int32_t i = 0; i < numTrees; i++)
{
pos = availablePositions[i];
ObjectEntryIndex type = OBJECT_ENTRY_INDEX_NULL;
auto* surfaceElement = map_get_surface_element_at(pos.ToCoordsXY());
if (surfaceElement == nullptr)
continue;
const auto* object = TerrainSurfaceObject::GetById(surfaceElement->GetSurfaceStyle());
if (MapGenSurfaceTakesGrassTrees(*object))
{
if (grassTreeIds.empty())
break;
type = grassTreeIds[util_rand() % grassTreeIds.size()];
}
else if (MapGenSurfaceTakesSandTrees(*object))
{
if (desertTreeIds.empty())
break;
if (util_rand() % 4 == 0)
type = desertTreeIds[util_rand() % desertTreeIds.size()];
}
else if (MapGenSurfaceTakesSnowTrees(*object))
{
if (snowTreeIds.empty())
break;
type = snowTreeIds[util_rand() % snowTreeIds.size()];
}
if (type != OBJECT_ENTRY_INDEX_NULL)
mapgen_place_tree(type, pos.ToCoordsXY());
}
}
/**