Wind Manager

Overview

The Zephyr Wind Manager (ZephyrWind) is the central controller for the Zephyr wind simulation system. It manages global wind direction, strength, gusts, flutter, and localized wind zones, synchronizing all parameters to shaders and connected components in real time.

This manager acts as a singleton — only one instance should exist in a scene at a time. All wind-aware shaders and systems reference this global instance to produce cohesive, physically consistent wind behavior.

Key Responsibilities

• Defines global wind direction and strength, transitioning smoothly toward target values.

• Simulates gusts and flutter using procedural noise textures.

• Manages local wind zones (ZephyrWindZone) via an internal octree system for efficient lookup.

• Sends all active wind data to the GPU for use in shaders.

• Provides CPU-side sampling of wind at any position in the scene.

• Offers debug visualization in the Scene view.

Internal Wind Simulation

Zephyr continuously updates wind simulation both in Play Mode and Edit Mode.

Direction and Strength Interpolation

Wind direction and strength smoothly interpolate toward target values using the Wind Acceleration Coefficient. This ensures natural transitions when the environment or gameplay logic changes wind settings.

Gusting and Flutter

Gusts and flutter are derived from a scrolling noise texture. Offsets advance each frame based on their respective speed and scale, producing a dynamic, looping pattern of turbulence.

Wind Zones

Wind zones (ZephyrWindZone) are managed through a Point Octree for fast spatial querying. Only zones within the Wind Zone Search Radius are evaluated, up to the limit defined by Max Wind Zones.

Best Practices

• Use a single ZephyrWind per scene.

• Adjust TargetWindStrength and TargetDirection through scripts for natural environmental changes (e.g., storms, seasons).

• Limit Max Wind Zones to 8–16 for performance balance.

• Always assign a wind noise texture.

Variables

Field	Type	Description
Direction Source	TransformForward / GlobalVector / LocalVector	Defines how the global wind direction is determined.
Target Wind Strength	float	Target wind intensity (recommended range: 0–5).
Wind Acceleration Coefficient	float	Determines how quickly the wind adjusts to new targets.
Gust Strength	float	Scales the strength of gusts relative to base wind.
Gust Scale	float	Controls the scale of the gust noise texture. Larger values = broader gust patterns.
Gust Speed	float	Controls how quickly gust patterns move through the scene.
Gust Pullback	float (0–1)	Determines how gust troughs can “pull back” against the main wind for chaotic motion.
Wind Noise Texture	Texture2D	Procedural noise used for gusting and flutter simulation.
Flutter Strength	float	Adds small perpendicular motion to simulate curling or turbulent wind.
Flutter Scale	float	Scale of the flutter noise pattern.
Flutter Speed	float	Speed of the flutter texture scroll.
Max Wind Zones	int	Maximum number of active wind zones considered per frame.
Wind Zone Search Radius	float	World radius used to gather nearby wind zones relative to the camera.

Properties

Property	Type	Description
Direction	Vector3	The current wind direction. To transition smoothly, set TargetDirection instead.
TargetDirection	Vector3	The target direction the wind should gradually turn toward.
WindStrength	float	The current base wind intensity.
Instance	ZephyrWind	Global singleton reference to the active wind manager.

GPU Integration

Zephyr synchronizes all wind parameters to shaders each frame through global shader variables:

Shader Property	Description
_WindDirection	Current global wind direction
_BaseWindStrength	Current global wind magnitude
_GustStrength, _GustScale, _GustSpeed, _GustPullback	Gusting parameters
_WindNoiseTexture	Noise map used for gust and flutter sampling
_FlutterStrength, _FlutterScale, _FlutterSpeed	Flutter parameters
_WindZones	Structured buffer of active wind zone data

Developers can read these in custom shaders to achieve synchronized wind movement across trees, grass, cloth, or particles. For more details, see the Shaders integration guide.

Example: Accessing Wind from Script

using UnityEngine;
using DistantLands.Zephyr;

public class ExampleWindReceiver : MonoBehaviour
{
    void Update()
    {
        Vector3 wind = ZephyrWind.Instance.GetWindAtPoint(transform.position);
        transform.position += wind * Time.deltaTime * 0.1f;
    }
}