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Mgfractal: Create a choice of 4 mandelbrot formulas

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paramat committed Nov 14, 2015
1 parent 4434498 commit 987d6a82f639126d5d8833739499150da286bdda
Showing with 51 additions and 7 deletions.
  1. +6 −1 builtin/settingtypes.txt
  2. +7 −1 minetest.conf.example
  3. +34 −5 src/mapgen_fractal.cpp
  4. +4 −0 src/mapgen_fractal.h
@@ -970,11 +970,16 @@ mgflat_np_cave2 (Mapgen flat cave2 noise parameters) noise_params 0, 12, (128, 1
[***Mapgen fractal]

# Map generation attributes specific to Mapgen fractal.
# 'julia' selects a julia set to be generated instead of a mandelbrot set.
# The 'julia' flag results in the corresponding julia set being generated.
# Flags that are not specified in the flag string are not modified from the default.
# Flags starting with "no" are used to explicitly disable them.
mgfractal_spflags (Mapgen fractal flags) flags nojulia julia,nojulia

# Choice of 4 mandelbrot set variations.
# 1 = 4D "Roundy" mandelbrot set, 2 = 4D "Squarry" mandelbrot set,
# 3 = 4D "Mandy Cousin" mandelbrot set, 4 = 4D mandelbrot set variation.
mgfractal_formula (Mapgen fractal formula) int 1 1 4

# Mandelbrot set: Iterations of the recursive function.
# Controls scale of finest detail.
mgfractal_m_iterations (Mapgen fractal mandelbrot iterations) int 9
@@ -1234,12 +1234,18 @@
#### Mapgen fractal

# Map generation attributes specific to Mapgen fractal.
# 'julia' selects a julia set to be generated instead of a mandelbrot set.
# The 'julia' flag results in the corresponding julia set being generated.
# Flags that are not specified in the flag string are not modified from the default.
# Flags starting with "no" are used to explicitly disable them.
# type: flags possible values: julia, nojulia
# mgfractal_spflags = nojulia

# Choice of 4 mandelbrot set variations.
# 1 = 4D "Roundy" mandelbrot set, 2 = 4D "Squarry" mandelbrot set,
# 3 = 4D "Mandy Cousin" mandelbrot set, 4 = 4D mandelbrot set variation.
# type: int
# mgfractal_formula = 1

# Mandelbrot set: Iterations of the recursive function.
# Controls scale of finest detail.
# type: int
@@ -67,6 +67,8 @@ MapgenFractal::MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *
MapgenFractalParams *sp = (MapgenFractalParams *)params->sparams;
this->spflags = sp->spflags;

this->formula = sp->formula;

this->m_iterations = sp->m_iterations;
this->m_scale = sp->m_scale;
this->m_offset = sp->m_offset;
@@ -145,6 +147,8 @@ MapgenFractalParams::MapgenFractalParams()
{
spflags = 0;

formula = 1;

m_iterations = 9; // Mandelbrot set only
m_scale = v3f(1024.0, 256.0, 1024.0);
m_offset = v3f(1.75, 0.0, 0.0);
@@ -170,6 +174,8 @@ void MapgenFractalParams::readParams(const Settings *settings)
{
settings->getFlagStrNoEx("mgfractal_spflags", spflags, flagdesc_mapgen_fractal);

settings->getU16NoEx("mgfractal_formula", formula);

settings->getU16NoEx("mgfractal_m_iterations", m_iterations);
settings->getV3FNoEx("mgfractal_m_scale", m_scale);
settings->getV3FNoEx("mgfractal_m_offset", m_offset);
@@ -195,6 +201,8 @@ void MapgenFractalParams::writeParams(Settings *settings) const
{
settings->setFlagStr("mgfractal_spflags", spflags, flagdesc_mapgen_fractal, U32_MAX);

settings->setU16("mgfractal_formula", formula);

settings->setU16("mgfractal_m_iterations", m_iterations);
settings->setV3F("mgfractal_m_scale", m_scale);
settings->setV3F("mgfractal_m_offset", m_offset);
@@ -403,11 +411,32 @@ bool MapgenFractal::getFractalAtPoint(s16 x, s16 y, s16 z)
u16 iterations = spflags & MGFRACTAL_JULIA ? j_iterations : m_iterations;

for (u16 iter = 0; iter < iterations; iter++) {
// 4D "Roundy" Mandelbrot set
float nx = ox * ox - oy * oy - oz * oz - ow * ow + cx;
float ny = 2.0f * (ox * oy + oz * ow) + cy;
float nz = 2.0f * (ox * oz + oy * ow) + cz;
float nw = 2.0f * (ox * ow + oy * oz) + cw;
float nx = 0.0f;
float ny = 0.0f;
float nz = 0.0f;
float nw = 0.0f;

if (formula == 1) { // 4D "Roundy" Mandelbrot Set
nx = ox * ox - oy * oy - oz * oz - ow * ow + cx;
ny = 2.0f * (ox * oy + oz * ow) + cy;
nz = 2.0f * (ox * oz + oy * ow) + cz;
nw = 2.0f * (ox * ow + oy * oz) + cw;
} else if (formula == 2) { // 4D "Squarry" Mandelbrot Set
nx = ox * ox - oy * oy - oz * oz - ow * ow + cx;
ny = 2.0f * (ox * oy + oz * ow) + cy;
nz = 2.0f * (ox * oz + oy * ow) + cz;
nw = 2.0f * (ox * ow - oy * oz) + cw;
} else if (formula == 3) { // 4D "Mandy Cousin" Mandelbrot Set
nx = ox * ox - oy * oy - oz * oz + ow * ow + cx;
ny = 2.0f * (ox * oy + oz * ow) + cy;
nz = 2.0f * (ox * oz + oy * ow) + cz;
nw = 2.0f * (ox * ow + oy * oz) + cw;
} else if (formula == 4) { // 4D Mandelbrot Set Variation
nx = ox * ox - oy * oy - oz * oz - ow * ow + cx;
ny = 2.0f * (ox * oy + oz * ow) + cy;
nz = 2.0f * (ox * oz - oy * ow) + cz;
nw = 2.0f * (ox * ow + oy * oz) + cw;
}

if (nx * nx + ny * ny + nz * nz + nw * nw > 4.0f)
return false;
@@ -36,6 +36,8 @@ extern FlagDesc flagdesc_mapgen_fractal[];
struct MapgenFractalParams : public MapgenSpecificParams {
u32 spflags;

u16 formula;

u16 m_iterations;
v3f m_scale;
v3f m_offset;
@@ -76,6 +78,8 @@ class MapgenFractal : public Mapgen {
v3s16 full_node_min;
v3s16 full_node_max;

u16 formula;

u16 m_iterations;
v3f m_scale;
v3f m_offset;

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