Quad Array Mesh

QuadArrayMesh.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using BaseX;

namespace FrooxEngine
{
    [Category("Assets/Procedural Meshes")]
    public class QuadArrayMesh : ProceduralMesh
    {
        public readonly SyncArray<float3> Points;
        public readonly SyncArray<float2> Sizes;
        public readonly SyncArray<floatQ> Rotations;
        public readonly SyncArray<color> Colors;
        public readonly SyncArray<float4> UVs;

        RangeModificationTracker invalidRange = new RangeModificationTracker();
        TriangleSubmesh submesh;
        Quad quad;

        protected override void OnAwake()
        {
            base.OnAwake();

            invalidRange.TrackArray(Points);
            invalidRange.TrackArray(Sizes);
            invalidRange.TrackArray(Rotations);
            invalidRange.TrackArray(Colors);
            invalidRange.TrackArray(UVs);
        }

        protected override IEnumerator<Context> UpdateMesh()
        {
            int uploadIndex = invalidRange.MinInvalidIndex;
            int uploadCount = MathX.Min(invalidRange.InvalidCount, MathX.Max(0, Points.Count - uploadIndex));

            if (uploadCount == 0)
                yield break;

            invalidRange.Reset();

            var _points = Points.GetBuffer();
            var _sizes = Sizes.GetBuffer();
            var _rotations = Rotations.GetBuffer();
            var _colors = Colors.GetBuffer();
            var _uvs = UVs.GetBuffer();

            yield return Context.ToBackground();

            submesh = submesh ?? meshx.TryGetSubmesh<TriangleSubmesh>();

            var newTrigCount = _points.count * Quad.TOTAL_TRIANGLES;
            var oldTrigCount = submesh.Count;

            meshx.SetVertexCount(_points.count * Quad.TOTAL_VERTICES);
            submesh.SetCount(newTrigCount);
            
            if(newTrigCount > oldTrigCount)
                for(int i = oldTrigCount; i < newTrigCount; i+=2)
                {
                    int vIndex = i << 1;
                    submesh.SetQuadAsTriangles(vIndex, vIndex + 1, vIndex + 2, vIndex + 3, i, i + 1);
                }

            quad = quad ?? new Quad(meshx.GetVertex(0));

            meshx.HasColors = _colors.count > 0;
            meshx.HasUV0s = true;
            meshx.HasNormals = true;
            meshx.HasTangents = true;

            if (meshx.HasColors)
                quad.Color = null;

            for(int i = uploadIndex; i < uploadIndex + uploadCount; i++)
            {
                quad.Position = _points[i];
                quad.Rotation = _rotations.GetElement(i, floatQ.Identity);
                quad.Size = _sizes.GetElement(i, float2.Zero);

                var uv = _uvs.GetElement(i, new float4(0f, 0f, 1f, 1f));
                quad.UVOffset = uv.xy - uv.zw * 0.5f;
                quad.UVScale = uv.zw;

                if (_colors.count != 0)
                    quad.Color = _colors.GetElement(i, color.White);

                quad.UpdateUnsafe(i * Quad.TOTAL_VERTICES);
            }
        }
    }
}