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Mgv7: Avoid divide-by-zero errors

Some settings of paramters can cause mgv7 variables to be -inf, nan or -nan.
This can cause massive vertical columns of water to appear above sea level.
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paramat committed Jun 24, 2017
1 parent 9a77397 commit 34e8e0e5ce2887391f55d5d7285088ec2c0f5761
Showing with 10 additions and 6 deletions.
  1. +8 −6 src/mapgen_v7.cpp
  2. +2 −0 src/mapgen_v7.h
@@ -59,7 +59,7 @@ MapgenV7::MapgenV7(int mapgenid, MapgenV7Params *params, EmergeManager *emerge)
this->large_cave_depth = params->large_cave_depth;
this->lava_depth = params->lava_depth;
this->float_mount_density = params->float_mount_density;
this->float_mount_height = params->float_mount_height;
float_mount_height_lim = MYMAX(params->float_mount_height, 1.0f);
this->floatland_level = params->floatland_level;
this->shadow_limit = params->shadow_limit;
this->cavern_limit = params->cavern_limit;
@@ -382,7 +382,8 @@ float MapgenV7::baseTerrainLevelFromMap(int index)

bool MapgenV7::getMountainTerrainAtPoint(s16 x, s16 y, s16 z)
{
float mnt_h_n = NoisePerlin2D(&noise_mount_height->np, x, z, seed);
float mnt_h_n =
MYMAX(NoisePerlin2D(&noise_mount_height->np, x, z, seed), 1.0f);
float density_gradient = -((float)y / mnt_h_n);
float mnt_n = NoisePerlin3D(&noise_mountain->np, x, y, z, seed);

@@ -392,7 +393,7 @@ bool MapgenV7::getMountainTerrainAtPoint(s16 x, s16 y, s16 z)

bool MapgenV7::getMountainTerrainFromMap(int idx_xyz, int idx_xz, s16 y)
{
float mounthn = noise_mount_height->result[idx_xz];
float mounthn = MYMAX(noise_mount_height->result[idx_xz], 1.0f);
float density_gradient = -((float)y / mounthn);
float mountn = noise_mountain->result[idx_xyz];

@@ -404,8 +405,8 @@ bool MapgenV7::getFloatlandMountainFromMap(int idx_xyz, int idx_xz, s16 y)
{
// Make rim 2 nodes thick to match floatland base terrain
float density_gradient = (y >= floatland_level) ?
-pow((float)(y - floatland_level) / float_mount_height, 0.75f) :
-pow((float)(floatland_level - 1 - y) / float_mount_height, 0.75f);
-pow((float)(y - floatland_level) / float_mount_height_lim, 0.75f) :
-pow((float)(floatland_level - 1 - y) / float_mount_height_lim, 0.75f);

float floatn = noise_mountain->result[idx_xyz] + float_mount_density;

@@ -421,7 +422,8 @@ void MapgenV7::floatBaseExtentFromMap(s16 *float_base_min, s16 *float_base_max,

float n_base = noise_floatland_base->result[idx_xz];
if (n_base > 0.0f) {
float n_base_height = noise_float_base_height->result[idx_xz];
float n_base_height =
MYMAX(noise_float_base_height->result[idx_xz], 1.0f);
float amp = n_base * n_base_height;
float ridge = n_base_height / 3.0f;
base_min = floatland_level - amp / 1.5f;
@@ -106,6 +106,8 @@ class MapgenV7 : public MapgenBasic {
Noise *noise_float_base_height;
Noise *noise_mountain;
Noise *noise_ridge;

float float_mount_height_lim;
};

#endif

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