Gizmos.DrawLine - thickens?

Questions & Answers
1

Hey,
i am somehow having problems to see a Gizmos.DrawLine in my editor (for debugging) is there a way to let the line appear thicker?, so at the moment its just this:

Gizmos.color = new Color (0,1F,0,1F);

		if (lastCompletedVectorPath != null) {
			for (int i=0;i<lastCompletedVectorPath.Count-1;i++) {
				Gizmos.DrawLine (lastCompletedVectorPath*,lastCompletedVectorPath[i+1]);*

  •  	}*

  •  }*
5

Really old question here. In case anyone else needs to do something similar here is an easy way to do it.

var p1 = startPosition;
var p2 = endPosition;
var thickness = 3;
Handles.DrawBezier(p1,p2,p1,p2, Color.red,null,thickness);
3

Bunny83’s version didn’t work directly, but the idea is good, so I’ve changed it a bit to work in screen coordinates and now it works better:

public static void DrawLine(Vector3 p1, Vector3 p2, float width)
{
	int count = 1 + Mathf.CeilToInt(width); // how many lines are needed.
	if (count == 1)
	{
		Gizmos.DrawLine(p1, p2);
	}
	else
	{
		Camera c = Camera.current;
		if (c == null)
		{
			Debug.LogError("Camera.current is null");
			return;
		}
		var scp1 = c.WorldToScreenPoint(p1);
		var scp2 = c.WorldToScreenPoint(p2);

		Vector3 v1 = (scp2 - scp1).normalized; // line direction
		Vector3 n = Vector3.Cross(v1, Vector3.forward); // normal vector

		for (int i = 0; i < count; i++)
		{
			Vector3 o = 0.99f * n * width * ((float)i / (count - 1) - 0.5f);
			Vector3 origin = c.ScreenToWorldPoint(scp1 + o);
			Vector3 destiny = c.ScreenToWorldPoint(scp2 + o);
			Gizmos.DrawLine(origin, destiny);
		}
	}
}
2

Unfortunately Unity doesn’t allow to change the line width. So lines drawn are always one pixel lines.

You can either:

  • Draw multiple lines in parallel slightly offset.
  • Draw actual quads instead of lines. However this has to be done with the GL class manually.

For simple debugging it’s easier to draw multiple lines. You can create a helper method like this:

public static void DrawLine(Vector3 p1, Vector3 p2, float width)
{
    int count = Mathf.CeilToInt(width); // how many lines are needed.
    if(count ==1)
        Gizmos.DrawLine(p1,p2);
    else
    {
        Camera c = Camera.current;
        if (c == null)
        {
            Debug.LogError("Camera.current is null")
            return;
        }
        Vector3 v1 = (p2 - p1).normalized; // line direction
        Vector3 v2 = (c.position - p1).normalized; // direction to camera
        Vector3 n = Vector3.Cross(v1,v2); // normal vector
        for(int i = 0; i < count; i++)
        {
            Vector3 o = n* width ((float)i/(count-1) - 0.5f);
            Gizmos.DrawLine(p1+o,p2+o);
        }
    }
}

I haven’t tested this method as i don’t have a Unity installation at hand, but it should work.

4

Here is an easy way to draw thick lines in the scene view and on standard cameras in the game view. (Note that I think the ‘thickness’ is expressed in pixels).

    public static void DrawThickLine(Vector3 start, Vector3 end, float thickness)
    {
        Camera c = Camera.current;
        if (c == null) return;

        // Only draw on normal cameras
        if (c.clearFlags == CameraClearFlags.Depth || c.clearFlags == CameraClearFlags.Nothing)
        {
            return;
        }

        // Only draw the line when it is the closest thing to the camera
        // (Remove the Z-test code and other objects will not occlude the line.)
        var prevZTest = Handles.zTest;
        Handles.zTest = UnityEngine.Rendering.CompareFunction.LessEqual;

        Handles.color = Gizmos.color;
        Handles.DrawAAPolyLine(thickness * 10, new Vector3[] { start, end });

        Handles.zTest = prevZTest;
    }
6

For those who are trying to adjust circle thickness, here’s how. This example is using normals applicable to the 2D case:

Handles.color = Color.green;
Handles.DrawWireArc(transform.position, transform.forward, transform.right, 360, 0.2f, 2.0f);