EARTHLIKE(1)

✨ EARTHLIKE 💅

okay so bestie, welcome to EARTHLIKE(1) — it lives in the User Commands section of the manual, and it is literally about to make you a whole planet 🪐✨

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🌍 NAME

earthlike — makes 6 images that form a cube map for an earth-like planet 🫶

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🎀 SYNOPSIS

earthlike [ -b bumps ] [ -B initialbumps ] [ -d dimension ] [ -c craters ] [ -h input-heightmap-data.png ] [ -H output-heightmap-prefix ] [ -k shrink-factor ] [ -l input-land-colors.png ] [ -L land-fraction ] [ -n normal-map-output-prefix ] [ -o terrain-output-prefix ] [ -O oceanlevel ] [ -r recursion-limit ] [ -s bump-scatter-factor ] [ -S random-seed ] [ -w input-water-colors.png ] [ -z initial-bumpsize ]

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💖 DESCRIPTION

So earthlike takes a bunch of input image data — land colors, water colors, and heightmap data — and produces 6 images that form a cube map texture for an earth-like planet. icon behavior honestly 🌈

Here's the vibe of how it actually works, bestie. Six square arrays of vectors (representing heights) get arranged into an over inflated cube. Then a number of initial "bumps" get applied. Each "bump" deforms the vector field away from its initial sphere by making a "pimple" on the surface 🍓 That pimple is modulated by heightfield data sampled from a random portion of the input heightmap data you gave it via the -h flag. And then that just... repeats over and over.

For each bump, smaller bumps are recursively added in the same vicinity until the bumps become "too small" — at which point the recursion stops, periodt. Once that whole process is done, the vector field now represents a sphere that has been deformed into something like terrain 👑

The altitude, plus the sampled value of a 3d noise function, are used to index into the provided land-color and water-color images to determine a set of output images forming the terrain cubemap. And on top of all that? Heightmap and normal map cubemaps get output too. no cap, she does it all 💜

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🦋 OPTIONS

• -b, --bumps — number of smaller bumps to recursively add to each bump. Default is 3. ✨
• -B, --initialbumps — number of initial bumps to add. Default is 60. 🔥
• -d, --dimension — size of the (square) output images in pixels. Default is 1024 (for 1024x1024 images), minimum is 128, maximum is 2048. 🌸
• -h, --height — name of the file containing input heightmap data. This should be an 8-bit/color RGB, non-interlaced PNG image file. 🎀
• -H, --heightmap-output — prefix for the name of the 6 output heightmap png image files. If this option is omitted but the -o option is used, then -heightmap is appended to the prefix specified for the -o option. If the -o option is also omitted, then heightmap will be used by default. 🧚
• -k, --shrink — factor by which to shrink "sub-bumps" relative to "bumps" in the recursive bump-adding algorithm. Default value is 0.55. 💫
• -l, --land — name of the land color png input file. This should be an 8-bit/color RGB, non-interlaced PNG image. 🌈
• -L, --land-fraction — approximate fraction of the planet that should be land. Range is 0.0 to 1.0. 🌍
• -n, --normal — name of the prefix to use for filenames of output normal map images. If this option is omitted but the -o option is used, then -normalmap is appended to the prefix specified for the -o option. If the -o option is also omitted, then normalmap will be used by default. ⭐
• -o, --output — name of the prefix to use for filenames of output terrain images. By default, terrainmap is used. 👑
• -O, --oceanlevel — value to use to determine sealevel. Default is 0.08. 🌊
• -r, --rlimit — recursion limit, specified as the smallest radius a bump is allowed to be before the recursion is terminated. Default is 0.005. 💀
• -s, --scatter — bump scatter factor, as a fraction of the radius of the bump. Default is 1.5. 🦋
• -S, --seed — random seed to use. Default is 31415. 🙈
• -w, --water — name of the input file to use for water colors; should be an 8-bit/color RGB, non-interlaced PNG image file. 💙
• -z, --bumpsize — radius of initial bumps, expressed as a multiplying factor of the planet radius. Default value is 0.04. 💅

lowkey a heads up: -c, --craters shows up in the synopsis, but it doesn't have its own entry in the options list — so I'm not gonna invent behavior for it 🤷‍♀️

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🍓 EXAMPLES

Here are some examples, bestie — steal them, they're iconic:

earthlike -B 400 -h heightdata.png -l land.png -w water.png -o yourplanet -S 31415 --bumpsize 0.5

earthlike -B 400 -b 1 -l cloud-gradient.png -w black-square.png -h ~/satellite-clouds.png -S 77573 --bumpsize 0.6 -o your-clouds

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🌟 SEE ALSO

• snis_client
• snis_server
• gaseous-giganticus
• howto-generate-earthlike-planets.txt

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okay that's the whole page, you ate that 💅✨ go make a planet fr fr 🪐🫶

— from the Space-Nerds-In-Space, dated Dec 2016, version EARTHLIKE(1) 🌈🎀 (yes that's the footer, and yes I made it cute, you're welcome bestie 💖)