From 987d6a82f639126d5d8833739499150da286bdda Mon Sep 17 00:00:00 2001
From: paramat <mat.gregory@virginmedia.com>
Date: Wed, 11 Nov 2015 05:05:20 +0000
Subject: [PATCH] Mgfractal: Create a choice of 4 mandelbrot formulas
---
builtin/settingtypes.txt | 7 ++++++-
minetest.conf.example | 8 +++++++-
src/mapgen_fractal.cpp | 39 ++++++++++++++++++++++++++++++++++-----
src/mapgen_fractal.h | 4 ++++
4 files changed, 51 insertions(+), 7 deletions(-)
diff --git a/builtin/settingtypes.txt b/builtin/settingtypes.txt
index 25849e0c7..e5fe5cb95 100644
--- a/builtin/settingtypes.txt
+++ b/builtin/settingtypes.txt
@@ -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
diff --git a/minetest.conf.example b/minetest.conf.example
index e5adc0e1d..74f7006f4 100644
--- a/minetest.conf.example
+++ b/minetest.conf.example
@@ -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
diff --git a/src/mapgen_fractal.cpp b/src/mapgen_fractal.cpp
index 5eebc17b3..37ed0d86a 100644
--- a/src/mapgen_fractal.cpp
+++ b/src/mapgen_fractal.cpp
@@ -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;
diff --git a/src/mapgen_fractal.h b/src/mapgen_fractal.h
index f3c023081..1b6683f1f 100644
--- a/src/mapgen_fractal.h
+++ b/src/mapgen_fractal.h
@@ -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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