Mgv7 spawn search: Cope with extreme custom terrain and biome 'dust'

Previously, maximum spawn level was set to 'water_level + 16'. This would result
in spawn search failing if terrain had been customised to be much higher than
'water_level' at all points.

Also raise spawn level by 1 node to avoid spawning half-buried in a biome 'dust'
node such as 'default:snowblock'.
master^2
paramat 2017-06-11 06:02:20 +01:00 committed by paramat
parent 8f2e60a961
commit ea4d407082
1 changed files with 24 additions and 14 deletions

View File

@ -202,10 +202,7 @@ void MapgenV7Params::writeParams(Settings *settings) const
int MapgenV7::getSpawnLevelAtPoint(v2s16 p)
{
// Base terrain calculation
s16 y = baseTerrainLevelAtPoint(p.X, p.Y);
// If enabled, check if inside a river
// If rivers are enabled, first check if in a river
if (spflags & MGV7_RIDGES) {
float width = 0.2;
float uwatern = NoisePerlin2D(&noise_ridge_uwater->np, p.X, p.Y, seed) * 2;
@ -213,28 +210,41 @@ int MapgenV7::getSpawnLevelAtPoint(v2s16 p)
return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point
}
// If mountains are disabled, terrain level is base terrain level
// Avoids spawn on non-existant mountain terrain
// Terrain noise 'offset' is the average level of that terrain.
// At least 50% of terrain will be below the higher of base and alt terrain
// 'offset's.
// Raising the maximum spawn level above 'water_level + 16' is necessary
// for when terrain 'offset's are set much higher than water_level.
s16 max_spawn_y = MYMAX(MYMAX(noise_terrain_alt->np.offset,
noise_terrain_base->np.offset),
water_level + 16);
// Base terrain calculation
s16 y = baseTerrainLevelAtPoint(p.X, p.Y);
// If mountains are disabled, terrain level is base terrain level.
// Avoids mid-air spawn where mountain terrain would have been.
if (!(spflags & MGV7_MOUNTAINS)) {
if (y <= water_level || y > water_level + 16)
if (y <= water_level || y > max_spawn_y)
return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point
else
return y;
// + 1 to not be half-buried in a potential node-deep biome 'dust'
return y + 1;
}
// Mountain terrain calculation
int iters = 128;
while (iters--) {
// Search upwards for first node without mountain terrain
int iters = 256;
while (iters > 0 && y <= max_spawn_y) {
if (!getMountainTerrainAtPoint(p.X, y + 1, p.Y)) { // If air above
if (y <= water_level || y > water_level + 16)
if (y <= water_level || y > max_spawn_y)
return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point
else
return y;
return y + 1;
}
y++;
iters--;
}
// Unsuitable spawn point, no mountain surface found
// Unsuitable spawn point
return MAX_MAP_GENERATION_LIMIT;
}