Fibonacci Sphere ( Unity3D )

README.md

FibonacciSphere.cs

using UnityEngine;

#if UNITY_EDITOR
using UnityEditor;
#endif

public class FibonacciSphere : MonoBehaviour
{
    [Range(0,500)] public int count = 200;
    [Range(0,2f)] public float radius = 1f;

    [HideInInspector] public float min = 0f;
    [HideInInspector] public float max = 1f;

    [Range(-180,180)]
    public float angleStart = 0f;
    
    [Range(0,360)]
    public float angleRange = 360f;

    public enum Direction { Up, Forward, Left, Right, Back, Down }

    public Direction direction = Direction.Up;

    /// <summary> -- golden angle in radians -- </summary>
    static float Phi = Mathf.PI * ( 3f - Mathf.Sqrt( 5f ) );

    static float Pi2 = Mathf.PI * 2;

    private void OnDrawGizmos( )
    {
        Gizmos.color = Color.red;
        
        for( var i = 0; i < count; ++i )
        {
            var _p = Point( radius, i, count, min, max, angleStart, angleRange );

            if( direction != Direction.Up ) _p = Shift( _p, direction );

            Gizmos.DrawSphere( transform.position + _p, 0.04f );
        }

    }
    public static Vector3 Point( float radius , int index , int total , float min = 0f, float max = 1f , float angleStartDeg = 0f, float angleRangeDeg = 360 )
    {
        // y goes from min (-) to max (+)
        var y = ( ( index / ( total - 1f ) ) * ( max - min ) + min ) * 2f - 1f;

        // https://stackoverflow.com/a/26127012/2496170

        // y goes from 1 to -1
        //var y = 1f - ( i / ( count - 1f ) ) * 2f; 

        // radius at y
        var rY = Mathf.Sqrt( 1 - y * y ); 
        
        // golden angle increment
        var theta = Phi * index ; 
        
        if( angleStartDeg != 0 || angleRangeDeg != 360 )
        {
            theta = ( theta % ( Pi2 ) ) ;
            theta = theta < 0 ? theta + Pi2 : theta ;
            
            var a1 = angleStartDeg * Mathf.Deg2Rad;
            var a2 = angleRangeDeg * Mathf.Deg2Rad;
            
            theta = theta * a2 / Pi2 + a1;
        }


        var x = Mathf.Cos( theta ) * rY;
        var z = Mathf.Sin( theta ) * rY;

        return  new Vector3( x, y, z ) * radius;
    }

    public static Vector3 Shift( Vector3 p, Direction direction = Direction.Up )
    {
        switch( direction )
        {
            default:
            case Direction.Up:          return new Vector3(  p.x,  p.y,  p.z ); 
            case Direction.Right:       return new Vector3(  p.y,  p.x,  p.z ); 
            case Direction.Left:        return new Vector3( -p.y,  p.x,  p.z );
            case Direction.Down:        return new Vector3(  p.x, -p.y,  p.z );
            case Direction.Forward:     return new Vector3(  p.x,  p.z,  p.y ); 
            case Direction.Back:        return new Vector3(  p.x,  p.z, -p.y );
        }
    }

    #if UNITY_EDITOR
    [CustomEditor(typeof(FibonacciSphere))]
    public class FibonacciSphereEditor : Editor
    {
        public override void OnInspectorGUI( )
        {
            EditorGUILayout.HelpBox("This MonoBehavious is used for gizmo visualization only , " + 
                "use the static methods of the FibonacciSphere class instead", MessageType.None);
            
            GUILayout.Space( 30 );
            
            base.OnInspectorGUI( );
            
            // Draw min max slider 

            var min = serializedObject.FindProperty("min");
            var max = serializedObject.FindProperty("max");

            var minVal = min.floatValue;
            var maxVal = max.floatValue;

            EditorGUI.BeginChangeCheck();
            
            EditorGUILayout.MinMaxSlider( "Min Max", ref minVal, ref maxVal, 0f, 1f );

            if( EditorGUI.EndChangeCheck() )
            {
                min.floatValue = minVal;
                max.floatValue = maxVal;
                
            }
            
            serializedObject.ApplyModifiedProperties();
        }
    }

    #endif
}