Confusion with Gizmo Matrix when using Gizmo Cube

Question

I'm trying to draw thick lines with Gizmos.DrawCube.

So far i've managed to position the Cube within the line points, yet i'm stumped on how to rotate the gizmo in-place to fit the line points direction.

I know i'm going to have to use Gizmo.matrix, but it ends up offsetting the points.

All i want is the rotation on the center of the gizmo.

alt text

    public static void GizmoDrawLine(Vector2 p1, Vector2 p2, float thickness, Transform t)
     {
         Gizmos.color = Color.red * 0.5f;
         Vector2 direction = p2 - p1;
         Gizmos.DrawCube(p1 + direction * 0.5f, new Vector3(direction.magnitude, thickness, 0f));
     }

Answer 1

Best Answer

Answer by VesuvianPrime · Feb 05, 2015 at 06:15 PM

You could use something like the following (untested) method:

 public static void DrawCube(Vector3 position, Quaternion rotation, Vector3 scale)
 {
     Matrix4x4 cubeTransform = Matrix4x4.TRS(position, rotation, scale);
     Matrix4x4 oldGizmosMatrix = Gizmos.matrix;
 
     Gixmos.matrix *= cubeTransform;
 
     Gizmos.DrawCube(Vector3.zero, Vector3.one);
 
     Gizmos.matrix = oldGizmosMatrix;
 }

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Hypellosh · Nov 11, 2015 at 03:01 PM 0

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This code works perfectly! Thanks!!

Naoweik · Sep 12, 2017 at 01:30 PM 0

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You saved my life, thanks !

Answer 2

Answer by idbrii · Sep 18, 2020 at 10:56 PM

To add to VesuvianPrime's great answer, since you have a Transform, you can use localToWorldMatrix to create your matrix. I think it's the same as Matrix4x4.TRS(transform.position, transform.rotation, transform.lossyScale).

However, you can't just plug that into your current GizmoDrawLine. But you could use it like this to make a frame around an object and follows its rotation:

 public static void GizmoDrawLine(float gap, Transform t)
 {
     var line = 0.07f;
     Gizmos.color = Color.red * 0.5f;
     Gizmos.matrix *= t.localToWorldMatrix;
     var height = new Vector3(line, line + gap * 2f, line);
     var width = new Vector3(line + gap * 2f, line, line);
     Gizmos.DrawCube(Vector3.right * gap, height);
     Gizmos.DrawCube(-Vector3.right * gap, height);
     Gizmos.DrawCube(Vector3.up * gap, width);
     Gizmos.DrawCube(-Vector3.up * gap, width);
 }

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Confusion with Gizmo Matrix when using Gizmo Cube

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