PhysicsShapeGroup2D.AddBox

Parameters

Returns

int Returns the shape index the shape was added to in the PhysicsShapeGroup2D. This index is used as the main reference when retrieving a shape.

Description

Adds a box shape (PhysicsShapeType2D.Polygon) to the shape group.

A box shape is a form of convex polygon with four vertices and an edgeRadius that extends around the four edges. The ability to add a box shape is a convenience only and does not represent an actual primitive shape.

NOTE: A box forms a closed shape and does have an interior therefore its interior is detectable by physics queries etc.

using UnityEngine;
using UnityEngine.Assertions;

public class Example : MonoBehaviour
{
    void Start()
    {
        CreateShape();
        GetShapeFromCollider();
    }

    // Create a custom shape.
    void CreateShape()
    {
        // Create a shape group.
        var shapeGroup = new PhysicsShapeGroup2D();

        // Add a Box (polygon with four vertices).
        // NOTE: Both the angle and edgeRadius arguments are optional.
        var shapeIndex = shapeGroup.AddBox
            (
                center: new Vector2(3f, 2f),
                size: new Vector2(1f, 1f),
                angle: 0f,
                edgeRadius: 0f
            );

        // Fetch the actual shape created.
        var physicsShape = shapeGroup.GetShape(shapeIndex);

        // Validate what we created.
        Assert.AreEqual(PhysicsShapeType2D.Polygon, physicsShape.shapeType);
        Assert.AreEqual(4, physicsShape.vertexCount);
        Assert.AreApproximatelyEqual(0f, physicsShape.radius);
    }

    // Get a physics shape from a Collider.
    void GetShapeFromCollider()
    {
        // Fetch the collider.
        var collider = GetComponent<BoxCollider2D>();

        // If the collider is not active and enabled then we'll get no shapes.
        // Let's just quit if not.
        if (!collider.isActiveAndEnabled)
            return;

        // Configure the collider.
        collider.offset = new Vector2(3f, 2f);
        collider.size = new Vector2(1f, 1f);

        // Create a shape group.
        var shapeGroup = new PhysicsShapeGroup2D();

        // Get the collider shapes.
        collider.GetShapes(shapeGroup);

        // Fetch the actual shape.
        var physicsShape = shapeGroup.GetShape(0);

        // Validate what we retrieved.
        Assert.AreEqual(PhysicsShapeType2D.Polygon, physicsShape.shapeType);
        Assert.AreEqual(4, physicsShape.vertexCount);
    }
}