WorldGeneration

Code at: https://github.com/OxillenGlow/MtSharpGrain/blob/main/src/main/resources/chunkgen.js

World Generation

Mtsharpgrain uses a deterministic, procedural world generation system to create its terrain. Every chunk is generated using a combination of mathematical functions and pseudo-randomness, ensuring consistency across the world and between game sessions.

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Overview

The world is divided into 16x16x16 chunks, and each chunk is generated independently using a seed value. The generation pipeline combines multiple layers of terrain features, including:

• Base heightmap (rolling sine/cosine waves)
• Sparse terrain features (mountains and slashes)
• Polar ice caps (linear cone-shaped ice layers)
• Subsurface layers (dirt/rock gradient and underground ores)
• Surface decorations (stray dirt/rock nubs)
• Chunk-level templates (rare storage structures)
• Spherical "ball" structures (glass shell with grass interior)

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Generation Pipeline

1. Deterministic Hash Function (hash2)

• A pure function that takes (ix, iz, seed) and returns a pseudo-random value in [0, 1).
• Used as the single source of randomness for all other functions, ensuring 100% order-independent and reproducible generation.

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2. Base Heightmap (baseHeight)

• A combination of three stacked sine/cosine waves at different frequencies and amplitudes.
• Creates a rolling, Mars-like dune terrain with a height range of roughly ±10 blocks.
• Formula:

  h += 6   * Math.sin(wx * 0.013 + seed)        * Math.cos(wz * 0.011 - seed);
  h += 3   * Math.sin(wx * 0.041 - seed * 0.7)  * Math.cos(wz * 0.037 + seed * 0.7);
  h += 1.2 * Math.sin(wx * 0.097 + seed * 1.3)  * Math.cos(wz * 0.083 - seed * 1.3);

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3. Sparse Terrain Features (terrainFeatureDelta)

• Mountains: Cone-shaped peaks with a radius of 40–150 blocks and a height of 20–80 blocks.
• Slashes: Capsule-shaped pits with a length of 200–1000 blocks, width of 20–60 blocks, and depth of 15–50 blocks.
• Features are spawned in ~40% of cells (20% mountains, 20% slashes).
• Features are placed on a coarse grid with a cell size of 600 blocks and a maximum reach of 600 blocks.

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4. Polar Ice Caps (iceThickness)

• A linear cone centered at the world origin (0, 0).
• Full thickness (10 blocks) at the origin, tapering to 0 at a radius of 10,000 blocks.
• Ice layers are raised by 1.5 blocks where they exist.

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5. Subsurface Layers

Dirt/Rock Gradient (subsurfaceBlock)

• The top 4 layers below the surface use a dirt/rock gradient based on depth:
  • 99% dirt at the topmost layer.
  • 80% dirt at the second layer.
  • 60% dirt at the third layer.
  • 10% dirt at the fourth layer.
• Below this, the terrain is pure rock.

Underground Materials (pickUndergroundBlock)

• Stone is the default underground block.
• Crystal Ore (block ID 5) has a chance of spawning that increases with depth:
  • Base chance: 1%
  • Increases by 0.06% per block below the surface (capped at 10%).

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6. Surface Decorations

• 2% chance of a stray dirt nub (block ID 3).
• 1% chance of a stray rock nub (block ID 2).
• 5% chance of an extra dirt block on top of the surface (only on dirt, not ice).

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7. Chunk-Level Templates

• All-Air Chunks: If a chunk is entirely above the surface, there is a 0.5% chance of replacing it with a storage template (storageAir).
• All-Underground Chunks: If a chunk is entirely below the surface, there is a 10% chance of replacing it with a storage template (storageGround).

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8. Spherical "Ball" Structures

• 5% of chunks that contain both air and ground will generate a spherical structure.
• Radius: 5–10 blocks.
• Composition:
  • Inner region: Dirt is replaced with grass (block ID 4).
  • Outer shell (2-block thick): Glass (block ID 10).
• Placement: Centered on the surface boundary (between air and ground).

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Block IDs

ID	Block Type
0	Air
2	Rock
3	Dirt
4	Grass
5	Crystal Ore
6	Ice
7	Not naturally spawned
8	Not naturally spawned
10	Glass

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Customization Tips

• Adjust the amplitudes and frequencies in baseHeight to change the rolling terrain shape.
• Modify the feature spawn rates in featureAt to control the density of mountains and slashes.
• Tweak the ice cap radius and thickness in iceThickness to change polar regions.
• Change the dirt/rock gradient in DIRT_CHANCE_BY_DEPTH to alter subsurface layers.
• Adjust the ore spawn chance in pickUndergroundBlock to control resource distribution.

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Performance Notes

• The generation is fully deterministic, meaning the same seed will always produce the same world.
• Chunks are generated independently, allowing for infinite world expansion without pre-generation.
• The use of hash2 ensures no reliance on Math.random(), making the system thread-safe and reproducible.