// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.

using System;
using osuTK;

namespace osu.Framework.Graphics.Primitives
{
    public interface IPolygon
    {
        /// <summary>
        /// The vertices that define the axes spanned by this polygon in screen-space counter-clockwise orientation.
        /// </summary>
        /// <remarks>
        /// Counter-clockwise orientation in screen-space coordinates is equivalent to a clockwise orientation in standard coordinates.
        /// <para>
        /// E.g. For the set of vertices { (0, 0), (1, 0), (0, 1), (1, 1) }, a counter-clockwise orientation is { (0, 0), (0, 1), (1, 1), (1, 0) }.
        /// </para>
        /// </remarks>
        /// <returns>The vertices that define the axes spanned by this polygon.</returns>
        ReadOnlySpan<Vector2> GetAxisVertices();

        /// <summary>
        /// Retrieves the vertices of this polygon in screen-space counter-clockwise orientation.
        /// </summary>
        /// <remarks>
        /// Counter-clockwise orientation in screen-space coordinates is equivalent to a clockwise orientation in standard coordinates.
        /// <para>
        /// E.g. For the set of vertices { (0, 0), (1, 0), (0, 1), (1, 1) }, a counter-clockwise orientation is { (0, 0), (0, 1), (1, 1), (1, 0) }.
        /// </para>
        /// </remarks>
        /// <returns>The vertices of this polygon.</returns>
        ReadOnlySpan<Vector2> GetVertices();
    }
}