Alembic Point Clouds to VFX Graph

AlembicPointCloudBinder.cs

using System;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEngine.Formats.Alembic.Importer;
using UnityEngine.VFX;
using UnityEngine.VFX.Utility;

namespace MTB.VFX
{
    [AddComponentMenu("VFX/Property Binders/MTB/Alembic Point Cloud")]
    [VFXBinder("MTB/Alembic Point Cloud")]
    sealed class AlembicPointCloudBinder : VFXBinderBase
    {
        public ExposedProperty PositionMapProperty = "PositionMap";
        public ExposedProperty PositionCountProperty = "PositionCount";
        public AlembicPointsCloud target;
        public bool EveryFrame = false;

        private Texture2D positionMap;
        private int count = 0;

        protected override void OnEnable()
        {
            base.OnEnable();
            UpdateTexture();
        }

        public override bool IsValid(VisualEffect component)
        {
            return target != null &&
                   component.HasTexture(PositionMapProperty) &&
                   component.HasInt(PositionCountProperty);
        }

        public override void UpdateBinding(VisualEffect component)
        {
            if (EveryFrame || Application.isEditor)
                UpdateTexture();

            component.SetTexture(PositionMapProperty, positionMap);
            component.SetInt(PositionCountProperty, count);
        }

        void UpdateTexture()
        {
            if (target == null || target.Positions.Count == 0)
                return;

            count = target.Positions.Count;
            var width = Mathf.CeilToInt(Mathf.Sqrt(count));

            positionMap = new Texture2D(width, width, TextureFormat.RGBAFloat, false)
                {
                    name = gameObject.name + "_PositionMap",
                    filterMode = FilterMode.Point,
                    wrapMode = TextureWrapMode.Repeat
                };

            var i1 = 0;
            var i2 = 0U;

            for (var y = 0; y < width; y++)
            {
                for (var x = 0; x < width; x++)
                {
                    var i = i1 < count ? i1 : (int) (i2 % count);
                    var p = target.Positions[i];

                    positionMap.SetPixel(x, y, new Color(p.x, p.y, p.z));
                    i1++;
                    i2 += 132049U; // prime
                }
            }
            positionMap.Apply();
        }
    }
}