Drawing Pie Shapes

[mrdave]

• ALINE version: 1.7.8
• Unity version: 6.1.9
• Render pipeline: URP

About Editor drawing. Gizmos

I want to draw a half circle, and in the future draw smaller and bigger pie shapes.
I cannot get the math right. It is showing as I want when the object is at 0,0,0 but it changes when the object is moved. I want the same shape and size to follow the object. Also, I want it to respect Y-axis rotation.
It is a gizmo for showing the object’s detection area.
Does anyone know the correct settings to use for this?
Here is the code I have now:

public class GetStartedGizmos : MonoBehaviourGizmos {
    public override void DrawGizmos () {
        using (Draw.InLocalSpace(transform)) {
            // Draw a cylinder at the object's position with a height of 2 and a radius of 0.5
            if (GizmoContext.InSelection(this))
            {
                var a1 = Mathf.PI * 0f;
                var a2 = Mathf.PI * 1f;
                var size = 8f;
                var arcStart = new Vector3(Mathf.Cos(a1), 0, Mathf.Sin(a1));
                var arcEnd = new Vector3(Mathf.Cos(a2), 0, Mathf.Sin(a2));
                var arcColor = Color.cyan * new Color(1, 1, 1, 0.5f);
                var startPoint = this.transform.position; 
                Draw.Line(startPoint, arcStart * size, arcColor);
                Draw.Line(startPoint, arcEnd * size, arcColor);
                Draw.Arc(startPoint, arcStart * size, arcEnd * size, arcColor);
                Draw.ArrowheadArc(startPoint, new float3(0,0,1f), 1f, arcColor);
            }
        }
    }
}

[aron_granberg]

Hi

Set startPoint to Vector3.zero, as you are drawing in local space.

[mrdave]

Thanks for the fast reply!

Wow! That simple! Thanks

[mrdave]

Do you have any tips on how to optimize the drawings? It is nice and fast, I mean how the code is written.

[aron_granberg]

Here’s one alternative way to do it. But if it’s that much simpler, I dunno.

@mrdave

using (Draw.InLocalSpace(transform)) {
            // Draw a cylinder at the object's position with a height of 2 and a radius of 0.5
            if (GizmoContext.InSelection(this))
            {
                using(Draw.WithColor(Color.cyan * new Color(1, 1, 1, 0.5f))) {
                    var a1 = Mathf.PI * 0f;
                    var a2 = Mathf.PI * 1f;
                    var size = 8f;
                    math.sincos(new float2(a1, a2), out var sin, out var cos);
                    var arcStart = new float2(cos.x, sin.x));
                    var arcEnd = new float2(cos.y, sin.y)));
                    Draw.xz.Line(float2.zero, arcStart * size);
                    Draw.xz.Line(float2.zero, arcEnd * size);
                    Draw.xz.Circle(float2.zero, size, a1, a2);
                    Draw.ArrowheadArc(float3.zero, new float3(0,0,1f), 1f);
                }
            }
        }

[mrdave]

Thanks. using Draw.WithColor is nice.
I think the Draw.xz are clearer as I’m not using all axis.

I am trying to put this on game objects. Don’t if I am doing it properly.

 public override void DrawGizmos () {
        using (Draw.InLocalSpace(transform)) {
            enemy = GetComponent<Enemy>();
            if (GizmoContext.InSelection(this))
            {

I guess I could try caching the component, but don’t know where. Does MBGizmos have an Awake method?

[mrdave]

Ok. I see that MBGizmos inherits from MB, so it does.

I tried using Start() but it didn’t seem to work. Going to try Awake.

also, I changed the position of my enemy line to be above the using statement.

 public override void DrawGizmos () {
       enemy = GetComponent<Enemy>(); 
       using (Draw.InLocalSpace(transform)) {

Don’t know if that helped, but it didn’t seem to break anything.