Curve2

Version: 1.0.0
Unity: 2022.3+

Adaptive tessellation curve system with segment-based composition and binary split caching.

Features

• Segment-based composition: Build complex paths from curve templates
• Adaptive binary tessellation: Subdivides only when queried, caches in binary tree
• Curve templates: Predefined curves (linear, up, down, left, right, swirl)
• Smooth connections: Automatic alignment of position and tangent between segments
• Full orientation: Position + rotation (tangent, normal, binormal)
• Performance: Lazy evaluation, minimal memory until needed

Quick Start

using Amanotes.Curve2;

// Create path with multiple segments
var path = new Curve2Path();
path.AddSegment("linear");
path.AddSegment("up");
path.AddSegment("right");
path.AddSegment("swirl");
path.Initialize();

// Get position and orientation at distance from start
WarpPoint warp = path.GetWarpPoint(5.5f);
transform.position = warp.position;
transform.rotation = warp.rotation;

API

Curve2Path

// Add segments
path.AddSegment(string curveId);           // Built-in preset
path.AddSegment(CurveTemplate template);   // Custom template

// Initialize (call after adding segments)
path.Initialize();

// Query
WarpPoint GetWarpPoint(float distance);
float TotalLength { get; }

Built-in Presets

• "linear" - Straight forward
• "up" - Curve upward
• "down" - Curve downward
• "left" - Curve left
• "right" - Curve right
• "swirl" - 90° spiral

Custom Templates

Create via Assets > Create > Curve2 > Curve Template:

[CreateAssetMenu(menuName = "Curve2/Curve Template")]
public class CurveTemplate : ScriptableObject
{
    public Vector3 p0, p1, p2, p3; // Bezier control points
}

Architecture

Curve2Path
  ├─ segments: List<Segment>
  │    ├─ curveId: string (template reference)
  │    ├─ transformedCurve: BezierCurve (aligned to previous)
  │    └─ startDistance, endDistance: float
  │
  └─ GetWarpPoint(distance) → WarpPoint

BezierCurve
  ├─ p0, p1, p2, p3: Vector3 (control points)
  ├─ TessellationCache (binary tree, lazy subdivision)
  └─ GetWarpPointByDistance(distance) → WarpPoint

WarpPoint
  ├─ position: Vector3
  └─ rotation: Quaternion (tangent + normal + binormal)

Binary Tessellation

• Starts with single segment [0, 1]
• Subdivides only when linear interpolation error > tolerance
• Caches split points in binary tree
• Deeper levels created on-demand when queried

Example:

Query at 0.5 → Split [0, 1] → Cache 0.5
Query at 0.25 → Split [0, 0.5] → Cache 0.25
Query at 0.75 → Split [0.5, 1] → Cache 0.75

Performance

• Lazy evaluation: No computation until GetWarpPoint() called
• Adaptive caching: Only subdivides where needed
• Memory efficient: Binary tree grows on-demand
• Inline optimized: Critical paths use AggressiveInlining

Migration from Existing Systems

From DRCurve/DRRoad:

// Old
float warpedZ = drCurve.Evaluate(time);

// New
WarpPoint warp = curve2Path.GetWarpPoint(distance);
transform.position = warp.position;
transform.rotation = warp.rotation;

From AnimationCurve:

// Old
float y = animCurve.Evaluate(x);

// New
var path = new Curve2Path();
path.AddSegment(customTemplate);
path.Initialize();
WarpPoint warp = path.GetWarpPoint(x);

License

Copyright © Amanotes. All rights reserved.