PhysicsShapeGroup2D.AddPolygon

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 polygon shape (PhysicsShapeType2D.Polygon) to the shape group.

A polygon shape is comprised of multiple edges (line segments) defined by all the specified vertices.

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

using System;
using System.Collections.Generic;
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 Polygon.
        var shapeIndex = shapeGroup.AddPolygon
            (
                vertices: new List<Vector2>
                {
                    new Vector2(-1f, -1f),
                    new Vector2(1f, -1f),
                    new Vector2(1f, 1f),
                    new Vector2(-1f, 1f)
                }
            );

        // 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);
    }

    // Get a physics shape from a Collider.
    void GetShapeFromCollider()
    {
        // Fetch the collider.
        var collider = GetComponent<PolygonCollider2D>();

        // 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.SetPath(0,
            new List<Vector2>()
            {
                new Vector2(-1f, -1f),
                new Vector2(1f, -1f),
                new Vector2(1f, 1f),
                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);
    }
}