Mesh line

This example demonstrates how to create a simple 3D scene with a custom mesh line connecting two objects. The code shows:

Setting up a basic 3D scene
Creating two sphere entities positioned in 3D space
Building a custom mesh line by:
- Defining vertices for start and end points
- Creating vertex and index buffers
- Configuring a mesh draw with line list primitive type
- Applying an emissive color material for visibility

The line is attached as a child to one of the spheres, creating a visual connection between the two objects. This approach illustrates how to create basic geometric primitives and custom line visualizations in a Stride 3D environment using low-level graphics APIs.

Note

This example requires the additional NuGet packages Stride.CommunityToolkit.Skyboxes and Stride.CommunityToolkit.Bepu. Make sure to install both before running the code.

Stride UI Example

View on GitHub.

using Stride.CommunityToolkit.Bepu;
using Stride.CommunityToolkit.Engine;
using Stride.CommunityToolkit.Rendering.Gizmos;
using Stride.CommunityToolkit.Rendering.ProceduralModels;
using Stride.CommunityToolkit.Skyboxes;
using Stride.Core.Mathematics;
using Stride.Engine;
using Stride.Graphics;
using Stride.Rendering;
using Buffer = Stride.Graphics.Buffer;

using var game = new Game();

game.Run(start: Start);

void Start(Scene rootScene)
{
    game.SetupBase3DScene();
    game.AddSkybox();

    var lineEntity = CreateLineEntity(game);

    var entity1 = CreateSphereEntity(game);
    entity1.Transform.Position = new Vector3(0, 8, 0);
    entity1.AddChild(lineEntity);

    var entity2 = CreateSphereEntity(game);
    entity2.Transform.Position = new Vector3(-0.01f, 9, -0.01f);

    entity1.Scene = rootScene;
    entity2.Scene = rootScene;
};

static Entity CreateSphereEntity(Game game)
    => game.Create3DPrimitive(PrimitiveModelType.Sphere);

static Entity CreateLineEntity(Game game)
{
    // Create vertex buffer with start and end points
    var vertices = new Vector3[] { new(0, 0, 0), new(1, 1, -1) };
    var vertexBuffer = Buffer.New(game.GraphicsDevice, vertices, BufferFlags.VertexBuffer);

    // Create index buffer
    var indices = new short[] { 0, 1 };
    var indexBuffer = Buffer.New(game.GraphicsDevice, indices, BufferFlags.IndexBuffer);

    var material = GizmoEmissiveColorMaterial.Create(game.GraphicsDevice, Color.DarkMagenta);
    // Or use this for a specific color
    //var material = game.CreateMaterial(Color.DarkMagenta);

    var meshDraw = new MeshDraw
    {
        PrimitiveType = PrimitiveType.LineList,
        VertexBuffers = [new VertexBufferBinding(vertexBuffer, new VertexDeclaration(VertexElement.Position<Vector3>()), vertices.Length)],
        IndexBuffer = new IndexBufferBinding(indexBuffer, is32Bit: false, indices.Length),
        DrawCount = indices.Length
    };

    var mesh = new Mesh { Draw = meshDraw };
    var model = new Model { mesh, material };

    return new Entity { new ModelComponent(model) };
}

Table of Contents

Mesh line

Note