Collidable Gizmo

A single-purpose demo of CollidableGizmoScript, which draws the collider Bepu is actually using so it can be compared against the model you think you gave it. The script draws every collider in the scene, so it sits on an empty entity of its own. The cube beside the row is created with Body set to BodyMode.None, which makes the point directly: the gizmo reports what physics knows about, and if nothing is drawn, nothing is there.

The Program.cs file shows how to:

Drawing the collider a body is really using
Hosting a scene-wide script on an empty entity
Leaving physics out with Body = BodyMode.None
Showing or hiding the gizmo with its Visible property
Diagnosing a body that does not collide as expected
The one-call form for a whole scene: game.AddPhysicsDebug()
Using helpers: SceneSetup3D, UseSkybox, CreatePrimitive, AddGrabber

Collidable Gizmo

View on GitHub.

using Stride.CommunityToolkit.Bepu;
using Stride.CommunityToolkit.Engine;
using Stride.CommunityToolkit.Rendering.ProceduralModels;
using Stride.CommunityToolkit.Skyboxes;
using Stride.Core.Mathematics;
using Stride.Engine;

using var game = new Game();

game.Run(new SceneSetup3D { Profiler = true }.UseBepu().UseSkybox(), start: Start);

void Start(Scene rootScene)
{
    // Left mouse grabs any body, drags it and throws it on release
    game.AddGrabber();

    // The script draws every collider in the scene, not its own entity's, so it lives on an entity of
    // its own. game.AddPhysicsDebug() makes this entity, with the debug meshes too
    var debug = new Entity("Physics Debug")
    {
        new CollidableGizmoScript
        {
            Color = new Color4(0.4f, 0.843f, 0, 0.9f),
            Visible = true
        }
    };
    debug.Scene = rootScene;

    // A cube without physics beside the row: no gizmo appears for it, because physics knows nothing of it
    var cube = game.CreatePrimitive(Primitive3D.Cube(), new() { Body = BodyMode.None });
    cube.Transform.Position = new Vector3(1f, 0.5f, 3f);
    cube.Scene = rootScene;

    CreateCubes(rootScene, 6);
}

void CreateCubes(Scene rootScene, int count)
{
    var half = count / 2;

    for (var i = -half; i < half; i++)
    {
        var entity = game.CreatePrimitive(Primitive3D.Cube());
        entity.Transform.Position = new Vector3(i * 0.99f, 1, 0);
        entity.Scene = rootScene;
    }
}

Table of Contents

Collidable Gizmo