unity-procedural-gen

Procedural Generation -- Design Translation Patterns

Prerequisite skills: unity-3d-math (noise math, spatial operations), unity-data-driven (ScriptableObject configs for generation parameters), unity-editor-tools (preview tooling, custom inspectors)

These patterns address the most common procedural generation failure: Claude generates procedural content with hardcoded algorithms and no designer control. The result works once but cannot be tuned, previewed, or constrained. Designers need knobs, constraints, and preview tools -- not just algorithm code. Every generation system should expose its parameters as ScriptableObject configs, support seed-based reproducibility, and provide editor previews.

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PATTERN 1: Noise-Based Generation

DESIGN INTENT: Designers want natural-feeling terrain ("rolling hills with occasional mountains") or placement ("dense forests with clearings"). They need to tune the character of randomness without touching code.

WRONG:

// Hardcoded single octave, no designer control, no reproducibility
float height = Mathf.PerlinNoise(x * 0.1f, y * 0.1f) * 10f;
terrain.SetHeight(x, y, height);

RIGHT: NoiseConfig ScriptableObject with frequency, amplitude, octaves, persistence, lacunarity, and offset. NoiseGenerator static utility class implements fractal Brownian motion (fBm) sampling. Supports domain warping for organic results. All parameters are designer-editable.

SCAFFOLD:

/// <summary>
/// Configuration for noise-based generation. Each biome or terrain type gets its own asset.
/// </summary>
[CreateAssetMenu(fileName = "New Noise Config", menuName = "ProcGen/Noise Config")]
public class NoiseConfig : ScriptableObject
{
    [Header("Base Noise")]
    [Range(0.001f, 1f)] public float frequency = 0.05f;
    [Range(0f, 100f)] public float amplitude = 10f;

    [Header("Fractal")]
    [Range(1, 8)] public int octaves = 4;
    [Range(0f, 1f)] public float persistence = 0.5f;
    [Range(1f, 4f)] public float lacunarity = 2f;

    [Header("Transform")]
    public Vector2 offset;
    [Range(0f, 1f)] public float domainWarpStrength = 0f;
}

/// <summary>
/// Stateless noise sampling utilities. Uses fBm for natural-looking results.
/// </summary>
public static class NoiseGenerator
{
    /// <summary>
    /// Samples 2D fractal Brownian motion noise at the given coordinates.
    /// </summary>
    /// <returns>Noise value scaled by config amplitude.</returns>
    public static float Sample2D(float x, float y, NoiseConfig config)
    {
        float sum = 0f;
        float freq = config.frequency;
        float amp = 1f;
        float maxAmp = 0f;

        for (int i = 0; i < config.octaves; i++)
        {
            float sampleX = (x + config.offset.x) * freq;
            float sampleY = (y + config.offset.y) * freq;
            sum += Mathf.PerlinNoise(sampleX, sampleY) * amp;
            maxAmp += amp;
            amp *= config.persistence;
            freq *= config.lacunarity;
        }

        return (sum / maxAmp) * config.amplitude;
    }
}