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-rw-r--r--src/mapgen_fractal.cpp86
-rw-r--r--src/mapgen_fractal.h12
2 files changed, 81 insertions, 17 deletions
diff --git a/src/mapgen_fractal.cpp b/src/mapgen_fractal.cpp
index 14dfe5c85..6c03c4ca9 100644
--- a/src/mapgen_fractal.cpp
+++ b/src/mapgen_fractal.cpp
@@ -66,7 +66,7 @@ MapgenFractal::MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *
MapgenFractalParams *sp = (MapgenFractalParams *)params->sparams;
this->spflags = sp->spflags;
- this->formula = sp->formula;
+ this->fractal = sp->fractal;
this->iterations = sp->iterations;
this->scale = sp->scale;
this->offset = sp->offset;
@@ -77,6 +77,9 @@ MapgenFractal::MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *
this->julia_z = sp->julia_z;
this->julia_w = sp->julia_w;
+ this->formula = fractal / 2 + fractal % 2;
+ this->julia = fractal % 2 == 0;
+
//// 2D terrain noise
noise_seabed = new Noise(&sp->np_seabed, seed, csize.X, csize.Z);
noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
@@ -141,7 +144,7 @@ MapgenFractalParams::MapgenFractalParams()
{
spflags = 0;
- formula = 1;
+ fractal = 1;
iterations = 11;
scale = v3f(4096.0, 1024.0, 4096.0);
offset = v3f(1.79, 0.0, 0.0);
@@ -163,7 +166,7 @@ void MapgenFractalParams::readParams(const Settings *settings)
{
settings->getFlagStrNoEx("mgfractal_spflags", spflags, flagdesc_mapgen_fractal);
- settings->getU16NoEx("mgfractal_formula", formula);
+ settings->getU16NoEx("mgfractal_fractal", fractal);
settings->getU16NoEx("mgfractal_iterations", iterations);
settings->getV3FNoEx("mgfractal_scale", scale);
settings->getV3FNoEx("mgfractal_offset", offset);
@@ -185,7 +188,7 @@ void MapgenFractalParams::writeParams(Settings *settings) const
{
settings->setFlagStr("mgfractal_spflags", spflags, flagdesc_mapgen_fractal, U32_MAX);
- settings->setU16("mgfractal_formula", formula);
+ settings->setU16("mgfractal_fractal", fractal);
settings->setU16("mgfractal_iterations", iterations);
settings->setV3F("mgfractal_scale", scale);
settings->setV3F("mgfractal_offset", offset);
@@ -368,7 +371,7 @@ bool MapgenFractal::getFractalAtPoint(s16 x, s16 y, s16 z)
{
float cx, cy, cz, cw, ox, oy, oz, ow;
- if (formula % 2 == 0) { // Julia sets, formula = 2, 4, 6, 8
+ if (julia) { // Julia set
cx = julia_x;
cy = julia_y;
cz = julia_z;
@@ -377,7 +380,7 @@ bool MapgenFractal::getFractalAtPoint(s16 x, s16 y, s16 z)
oy = (float)y / scale.Y - offset.Y;
oz = (float)z / scale.Z - offset.Z;
ow = slice_w;
- } else { // Mandelbrot sets, formula = 1, 3, 5, 7
+ } else { // Mandelbrot set
cx = (float)x / scale.X - offset.X;
cy = (float)y / scale.Y - offset.Y;
cz = (float)z / scale.Z - offset.Z;
@@ -388,32 +391,87 @@ bool MapgenFractal::getFractalAtPoint(s16 x, s16 y, s16 z)
ow = 0.0f;
}
+ float nx = 0.0f;
+ float ny = 0.0f;
+ float nz = 0.0f;
+ float nw = 0.0f;
+
for (u16 iter = 0; iter < iterations; iter++) {
- float nx = 0.0f;
- float ny = 0.0f;
- float nz = 0.0f;
- float nw = 0.0f;
- if (formula == 1 || formula == 2) { // 4D "Roundy" Mandelbrot/Julia Set
+ if (formula == 1) { // 4D "Roundy"
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 || formula == 4) { // 4D "Squarry" Mandelbrot/Julia Set
+ } else if (formula == 2) { // 4D "Squarry"
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 == 5 || formula == 6) { // 4D "Mandy Cousin" Mandelbrot/Julia Set
+ } else if (formula == 3) { // 4D "Mandy Cousin"
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 == 7 || formula == 8) { // 4D "Variation" Mandelbrot/Julia Set
+ } else if (formula == 4) { // 4D "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;
+ } else if (formula == 5) { // 3D "Mandelbrot/Mandelbar"
+ nx = ox * ox - oy * oy - oz * oz + cx;
+ ny = 2.0f * ox * oy + cy;
+ nz = -2.0f * ox * oz + cz;
+ } else if (formula == 6) { // 3D "Christmas Tree"
+ // Altering the formula here is necessary to avoid division by zero
+ if (fabs(oz) < 0.000000001f) {
+ nx = ox * ox - oy * oy - oz * oz + cx;
+ ny = 2.0f * oy * ox + cy;
+ nz = 4.0f * oz * ox + cz;
+ } else {
+ float a = (2.0f * ox) / (sqrt(oy * oy + oz * oz));
+ nx = ox * ox - oy * oy - oz * oz + cx;
+ ny = a * (oy * oy - oz * oz) + cy;
+ nz = a * 2.0f * oy * oz + cz;
+ }
+ } else if (formula == 7) { // 3D "Mandelbulb"
+ if (fabs(oy) < 0.000000001f) {
+ nx = ox * ox - oz * oz + cx;
+ ny = cy;
+ nz = -2.0f * oz * sqrt(ox * ox) + cz;
+ } else {
+ float a = 1.0f - (oz * oz) / (ox * ox + oy * oy);
+ nx = (ox * ox - oy * oy) * a + cx;
+ ny = 2.0f * ox * oy * a + cy;
+ nz = -2.0f * oz * sqrt(ox * ox + oy * oy) + cz;
+ }
+ } else if (formula == 8) { // 3D "Cosine Mandelbulb"
+ if (fabs(oy) < 0.000000001f) {
+ nx = 2.0f * ox * oz + cx;
+ ny = 4.0f * oy * oz + cy;
+ nz = oz * oz - ox * ox - oy * oy + cz;
+ } else {
+ float a = (2.0f * oz) / sqrt(ox * ox + oy * oy);
+ nx = (ox * ox - oy * oy) * a + cx;
+ ny = 2.0f * ox * oy * a + cy;
+ nz = oz * oz - ox * ox - oy * oy + cz;
+ }
+ } else if (formula == 9) { // 4D "Mandelbulb"
+ float rxy = sqrt(ox * ox + oy * oy);
+ float rxyz = sqrt(ox * ox + oy * oy + oz * oz);
+ if (fabs(ow) < 0.000000001f && fabs(oz) < 0.000000001f) {
+ nx = (ox * ox - oy * oy) + cx;
+ ny = 2.0f * ox * oy + cy;
+ nz = -2.0f * rxy * oz + cz;
+ nw = 2.0f * rxyz * ow + cw;
+ } else {
+ float a = 1.0f - (ow * ow) / (rxyz * rxyz);
+ float b = a * (1.0f - (oz * oz) / (rxy * rxy));
+ nx = (ox * ox - oy * oy) * b + cx;
+ ny = 2.0f * ox * oy * b + cy;
+ nz = -2.0f * rxy * oz * a + cz;
+ nw = 2.0f * rxyz * ow + cw;
+ }
}
if (nx * nx + ny * ny + nz * nz + nw * nw > 4.0f)
diff --git a/src/mapgen_fractal.h b/src/mapgen_fractal.h
index 7d31a43b8..3d4f7ee8f 100644
--- a/src/mapgen_fractal.h
+++ b/src/mapgen_fractal.h
@@ -3,6 +3,9 @@ Minetest
Copyright (C) 2010-2015 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
Copyright (C) 2010-2015 paramat, Matt Gregory
+Fractal formulas from http://www.bugman123.com/Hypercomplex/index.html
+by Paul Nylander, and from http://www.fractalforums.com, thank you.
+
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
@@ -33,7 +36,7 @@ extern FlagDesc flagdesc_mapgen_fractal[];
struct MapgenFractalParams : public MapgenSpecificParams {
u32 spflags;
- u16 formula;
+ u16 fractal;
u16 iterations;
v3f scale;
v3f offset;
@@ -63,14 +66,17 @@ public:
int ystride;
int zstride;
- u32 spflags;
+ u16 formula;
+ bool julia;
v3s16 node_min;
v3s16 node_max;
v3s16 full_node_min;
v3s16 full_node_max;
- u16 formula;
+ u32 spflags;
+
+ u16 fractal;
u16 iterations;
v3f scale;
v3f offset;
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-03 02:01:45 +0000