Add A Custom VertexElement

[Bodyclock-Games]

Hi All, a newcomer to Stride from Unity and I'm looking to port some of my C# modules to Stride. One of these is a terrain system that uses custom VertexAttributes to store data such as slope and aspect in a Vector4. Is it possible to add a custom VertexElement type to the VertexElement struct or is that structure constrained to the requirements of DX11. This is lower level code than I'm used to and I don't want to mess this up.
Or can I just declare an additional TextureCoordinate in a custom VertexPositionNormalColor type struct.
Or alternatively is there a better way to do this?
Cheers
Chris

[NicusorN5]

Hi, a starting point is ths: https://doc.stride3d.net/4.1/en/manual/graphics/low-level-api/draw-vertices.html

This article describes creating a vertex buffer, a vertex declaration and finally drawing the vertex buffer.

[ly3027929699]

if you want to define an ext texturecoord, write a custom shader

[Bodyclock-Games]

Many thanks for the answers. This is what I have so far. Does this look reasonable?

`using System;
using System.Runtime.InteropServices;
using Stride.Graphics;
using Stride.Core.Mathematics;

namespace Bodyclock.Stride.Terrain
{
[StructLayout(LayoutKind.Sequential, Pack = 4)]
public struct TerrainVertex : IEquatable, IVertex
{
public Vector3 Position;
public Vector3 Normal;
public Vector4 Attributes;
public Color Color;

    public static readonly int Size = Marshal.SizeOf(typeof(TerrainVertex));

    public static readonly VertexDeclaration Layout = new(
    VertexElement.Position<Vector3>(),
    VertexElement.Normal<Vector3>(),
    new VertexElement("ATTRIBUTES", PixelFormat.R32G32B32A32_Float),
    VertexElement.Color<Color>());

    public TerrainVertex(Vector3 position, Vector3 normal, Vector4 attributes, Color color)
    {
        this = default;
        Position = position;
        Normal = normal;
        Attributes = attributes;
        Color = color;
    }

    public VertexDeclaration GetLayout() => Layout;
    public void FlipWinding() { }
    public bool Equals(TerrainVertex other)
    {
        if (Position.Equals(other.Position) && Normal.Equals(other.Normal) && Attributes.Equals(other.Attributes))
            return Color.Equals(other.Color);
        return false;
    }

    public override bool Equals(object obj)
    {
        if (obj == null) return false;
        if (obj is TerrainVertex vertex) return Equals(vertex);
        return false;
    }

    public override int GetHashCode()
    {
        unchecked
        {
            int hashCode = Position.GetHashCode();
            hashCode = (hashCode * 397) ^ Normal.GetHashCode();
            hashCode = (hashCode * 397) ^ Attributes.GetHashCode();
            hashCode = (hashCode * 397) ^ Color.GetHashCode();
            return hashCode;
        }
    }
    public static bool operator ==(TerrainVertex left, TerrainVertex right)
    {
        return left.Equals(right);
    }
    public static bool operator !=(TerrainVertex left, TerrainVertex right)
    {
        return !left.Equals(right);
    }
    public override string ToString()
    {
        return $"Position: {Position}, Normal: {Normal}, Attributes: {Attributes}, Color: {Color}";
    }
}

}`

[ly3027929699]

using the TerrainVertex.Layout when creating a vetexbuffer, and it' will be done. link: https://doc.stride3d.net/4.1/en/manual/graphics/low-level-api/draw-vertices.html. Also, you can check the UnitTest of stride's source. It hsa some samples of drawing

[ly3027929699]

[Ethereal77]

This would be a nice thing to have in the docs.