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author | Duane Robertson <duane@duanerobertson.com> | 2016-02-26 20:41:13 -0600 |
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committer | paramat <mat.gregory@virginmedia.com> | 2016-02-27 21:27:32 +0000 |
commit | 6969dd4224d0f309e006edf50b8eb1a188fc1254 (patch) | |
tree | 56ae51ba5625e5dacf85bad019de18e8abb6e413 /src | |
parent | 158bd76e8796c70f94e67bc3be44c88101dcf9b2 (diff) | |
download | minetest-6969dd4224d0f309e006edf50b8eb1a188fc1254.tar.gz minetest-6969dd4224d0f309e006edf50b8eb1a188fc1254.tar.bz2 minetest-6969dd4224d0f309e006edf50b8eb1a188fc1254.zip |
Mgvalleys: Add Dry Riverbeds
Lower water table where base humidity is low.
Alter heat and humidity to compensate for river humidity and altitude
chill.
Correct misuse of surface_max_y in generateTerrain.
Remove sand trails in the water at river mouths.
Remove river water below water_level.
Correct heat/humidity calculations where noises are less than zero.
Correct heightmap errors as much as possible.
Make humidity calculations more readable.
Diffstat (limited to 'src')
-rw-r--r-- | src/mapgen_valleys.cpp | 140 |
1 files changed, 105 insertions, 35 deletions
diff --git a/src/mapgen_valleys.cpp b/src/mapgen_valleys.cpp index 2f96c3397..f9625746b 100644 --- a/src/mapgen_valleys.cpp +++ b/src/mapgen_valleys.cpp @@ -399,8 +399,21 @@ void MapgenValleys::calculateNoise() //mapgen_profiler->avg("noisemaps", tcn.stop() / 1000.f); + float heat_offset = 0.f; + float humidity_scale = 1.f; + + // Altitude chill tends to reduce the average heat. + if (use_altitude_chill) + heat_offset = 5.f; + + // River humidity tends to increase the humidity range. + if (humid_rivers) { + humidity_scale = 0.8f; + } + for (s32 index = 0; index < csize.X * csize.Z; index++) { - noise_heat->result[index] += noise_heat_blend->result[index]; + noise_heat->result[index] += noise_heat_blend->result[index] + heat_offset; + noise_humidity->result[index] *= humidity_scale; noise_humidity->result[index] += noise_humidity_blend->result[index]; } @@ -481,9 +494,10 @@ float MapgenValleys::terrainLevelFromNoise(TerrainNoise *tn) } // base - depth : height of the bottom of the river - // water_level - 6 : don't make rivers below 6 nodes under the surface + // water_level - 3 : don't make rivers below 3 nodes under the surface + // We use three because that's as low as the swamp biomes go. // There is no logical equivalent to this using rangelim. - mount = MYMIN(MYMAX(base - depth, (float) (water_level - 6)), mount); + mount = MYMIN(MYMAX(base - depth, (float)(water_level - 3)), mount); // Slope has no influence on rivers. *tn->slope = 0.f; @@ -503,7 +517,7 @@ float MapgenValleys::adjustedTerrainLevelFromNoise(TerrainNoise *tn) for (s16 y = y_start; y <= y_start + 1000; y++) { float fill = NoisePerlin3D(&noise_inter_valley_fill->np, tn->x, y, tn->z, seed); - if (fill * *tn->slope <= y - mount) { + if (fill * *tn->slope < y - mount) { mount = MYMAX(y - 1, mount); break; } @@ -552,6 +566,15 @@ float MapgenValleys::terrainLevelAtPoint(s16 x, s16 z) int MapgenValleys::generateTerrain() { + // Raising this reduces the rate of evaporation. + static const float evaporation = 300.f; + // from the lua + static const float humidity_dropoff = 4.f; + // constant to convert altitude chill (compatible with lua) to heat + static const float alt_to_heat = 20.f; + // humidity reduction by altitude + static const float alt_to_humid = 10.f; + MapNode n_air(CONTENT_AIR); MapNode n_river_water(c_river_water_source); MapNode n_sand(c_sand); @@ -564,42 +587,56 @@ int MapgenValleys::generateTerrain() for (s16 z = node_min.Z; z <= node_max.Z; z++) for (s16 x = node_min.X; x <= node_max.X; x++, index_2d++) { - s16 river_y = floor(noise_rivers->result[index_2d]); - s16 surface_y = floor(noise_terrain_height->result[index_2d]); + float river_y = noise_rivers->result[index_2d]; + float surface_y = noise_terrain_height->result[index_2d]; float slope = noise_inter_valley_slope->result[index_2d]; + float t_heat = noise_heat->result[index_2d]; - heightmap[index_2d] = surface_y; + heightmap[index_2d] = -MAX_MAP_GENERATION_LIMIT; if (surface_y > surface_max_y) - surface_max_y = surface_y; + surface_max_y = ceil(surface_y); + + if (humid_rivers) { + // Derive heat from (base) altitude. This will be most correct + // at rivers, since other surface heights may vary below. + if (use_altitude_chill && (surface_y > 0.f || river_y > 0.f)) + t_heat -= alt_to_heat * MYMAX(surface_y, river_y) / altitude_chill; + + // If humidity is low or heat is high, lower the water table. + float delta = noise_humidity->result[index_2d] - 50.f; + if (delta < 0.f) { + float t_evap = (t_heat - 32.f) / evaporation; + river_y += delta * MYMAX(t_evap, 0.08f); + } + } u32 index_3d = (z - node_min.Z) * zstride + (x - node_min.X); u32 index_data = vm->m_area.index(x, node_min.Y - 1, z); // Mapgens concern themselves with stone and water. for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) { - float fill = 0.f; - fill = noise_inter_valley_fill->result[index_3d]; - if (vm->m_data[index_data].getContent() == CONTENT_IGNORE) { - bool river = (river_y > surface_y); + float fill = noise_inter_valley_fill->result[index_3d]; + float surface_delta = (float)y - surface_y; + bool river = y + 1 < river_y; - if (river && y == surface_y) { + if (fabs(surface_delta) <= 0.5f && y > water_level && river) { // river bottom vm->m_data[index_data] = n_sand; - } else if (river && y <= surface_y) { + } else if (slope * fill > surface_delta) { // ground vm->m_data[index_data] = n_stone; - } else if (river && y < river_y) { - // river - vm->m_data[index_data] = n_river_water; - } else if ((!river) && myround(fill * slope) >= y - surface_y) { - // ground - vm->m_data[index_data] = n_stone; - heightmap[index_2d] = surface_max_y = y; + if (y > heightmap[index_2d]) + heightmap[index_2d] = y; + if (y > surface_max_y) + surface_max_y = y; } else if (y <= water_level) { // sea vm->m_data[index_data] = n_water; + } else if (river) { + // river + vm->m_data[index_data] = n_river_water; } else { vm->m_data[index_data] = n_air; } @@ -609,18 +646,51 @@ int MapgenValleys::generateTerrain() index_3d += ystride; } - // Although the original valleys adjusts humidity by distance - // from seawater, this causes problems with the default biomes. - // Adjust only by freshwater proximity. - const float humidity_offset = 0.8f; // derived by testing - if (humid_rivers) - noise_humidity->result[index_2d] *= (1 + pow(0.5f, MYMAX((surface_max_y - - noise_rivers->result[index_2d]) / 3.f, 0.f))) * humidity_offset; - - // Assign the heat adjusted by altitude. - if (use_altitude_chill && surface_max_y > 0) - noise_heat->result[index_2d] *= - pow(0.5f, (surface_max_y - altitude_chill / 3.f) / altitude_chill); + // This happens if we're generating a chunk that doesn't + // contain the terrain surface, in which case, we need + // to set heightmap to a value outside of the chunk, + // to avoid confusing lua mods that use heightmap. + if (heightmap[index_2d] == -MAX_MAP_GENERATION_LIMIT) { + s16 surface_y_int = myround(surface_y); + if (surface_y_int > node_max.Y + 1 || surface_y_int < node_min.Y - 1) { + // If surface_y is outside the chunk, it's good enough. + heightmap[index_2d] = surface_y_int; + } else { + // If the ground is outside of this chunk, but surface_y + // is within the chunk, give a value outside. + heightmap[index_2d] = node_min.Y - 2; + } + } + + if (humid_rivers) { + // Use base ground (water table) in a riverbed, to + // avoid an unnatural rise in humidity. + float t_alt = MYMAX(noise_rivers->result[index_2d], (float)heightmap[index_2d]); + float humid = noise_humidity->result[index_2d]; + float water_depth = (t_alt - river_y) / humidity_dropoff; + humid *= 1.f + pow(0.5f, MYMAX(water_depth, 1.f)); + + // Reduce humidity with altitude (ignoring riverbeds). + // This is similar to the lua version's seawater adjustment, + // but doesn't increase the base humidity, which causes + // problems with the default biomes. + if (t_alt > 0.f) + humid -= alt_to_humid * t_alt / altitude_chill; + + noise_humidity->result[index_2d] = humid; + } + + // Assign the heat adjusted by any changed altitudes. + // The altitude will change about half the time. + if (use_altitude_chill) { + // ground height ignoring riverbeds + float t_alt = MYMAX(noise_rivers->result[index_2d], (float)heightmap[index_2d]); + if (humid_rivers && heightmap[index_2d] == (s16)myround(surface_y)) + // The altitude hasn't changed. Use the first result. + noise_heat->result[index_2d] = t_heat; + else if (t_alt > 0.f) + noise_heat->result[index_2d] -= alt_to_heat * t_alt / altitude_chill; + } } return surface_max_y; @@ -645,7 +715,7 @@ MgStoneType MapgenValleys::generateBiomes(float *heat_map, float *humidity_map) // generated mapchunk or if not, a node of overgenerated base terrain. content_t c_above = vm->m_data[vi + em.X].getContent(); bool air_above = c_above == CONTENT_AIR; - bool water_above = (c_above == c_water_source); + bool water_above = (c_above == c_water_source || c_above == c_river_water_source); // If there is air or water above enable top/filler placement, otherwise force // nplaced to stone level by setting a number exceeding any possible filler depth. @@ -714,7 +784,7 @@ MgStoneType MapgenValleys::generateBiomes(float *heat_map, float *humidity_map) water_above = true; } else if (c == c_river_water_source) { vm->m_data[vi] = MapNode(biome->c_river_water); - nplaced = U16_MAX; // Sand was already placed under rivers. + nplaced = depth_top; // Enable filler placement for next surface air_above = false; water_above = true; } else if (c == CONTENT_AIR) { |