island

Simple Island Generator and Renderer

Algorithm

Requirements

1. C++ compiler
2. Python 3
3. Python modules: pypng and Pillow.

Compile the generators (at the moment, only Simplex):

$ make

Now, you'll get a SimplexIslandGen executable in the bin/ directory.

Generating an Island

$ bin/SimplexIslandGen
Usage: ./SimplexIslandGen SIZE OUTPUT-FILENAME [SEED or "SEED=unset"] [LOWER-BOUND UPPER-BOUND]

Only SIZE and OUTPUT-FILENAME are necessary.

To generate, for example, an island of size 1024 x 1024:

$ bin/SimplexIslandGen 1024 island.hmap
Image size: 1024
Saving data to filename: island.hmap
Seed (unique ID): 929654437
Lower bound: 0
Upper bound: 1

The program will output island.hmap, containing the height values generated.

Now you can render this file into an image:

Adjusting the LOWER-BOUND UPPER-BOUND argument can make the island's shape much more interesting. For example, try:

$ bin/SimplexIslandGen 1024 island.hmap SEED=unset -0.25 1.0
Image size: 1024
Saving data to filename: island.hmap
Seed (unique ID): 73068098
Lower bound: -0.25
Upper bound: 1

Rendering an Island

Two Python scripts are provided for rendering the .hmap files: IslandRender.py and Island3DRender.py.

Simple 2D Rendering

Use the provided IslandRender.py with a .hmap file generated.

For example, using the island.hmap we generated before:

$ python3 IslandRender.py island.hmap island.png

Outputs a PNG file with the rendered island divided into water/land.

Render heights as colors

Add the flag --mode=color-heights.

$ python3 IslandRender.py island.hmap island.png --mode=color-heights

Render biomes

Generate another file, of same size as the .hmap, like this:

$ bin/SimplexIslandGen 1024 island.biome
Image size: 1024
Saving data to filename: island.biome
Seed (unique ID): 2007696746
Lower bound: 0
Upper bound: 1

Now use IslandRender.py like this:

$ python3 IslandRender.py island.hmap island.png --mode=biome --biome-file=island.biome

The island.biome is a moisture map.

Biomes are calculated as a function of elevation and moisture. See the biome(elevation, moisture) function in IslandRender.py to adjust it.

Colors

Colors for the rendering are defined in IslandRenderColors.json. Modify it to your liking.

Other Options

Run IslandRender.py with --help.

3D Rendering

Needs the following modules: numpy, matplotlib.

Renders the island as an x, y, z graph using matplotlib. Slow.

Algorithm

For now, only the Simplex algorithm is implemented.

I made a custom Simplex generator inspired by python-rpg's version, since neither LibNoise, nor FastNoise provided the customization I wanted.

File Formats

The .hmap and .biome files generated are simply space-and-newline separated file, containing height/moisture values.