smrendererv3/SMCode/SM2D/Controls/Mouse2D.cs

using System.Collections.Generic;
using OpenTK;
using SM.Base.Controls;
using SM.Base.Scene;
using SM.OGL.Mesh;
using SM2D.Scene;
using SM2D.Types;

namespace SM2D.Controls
{
    /// <summary>
    /// Contains special methods for the mouse.
    /// </summary>
    public class Mouse2D
    {
        /// <summary>
        /// Returns the current position of the mouse inside the world.
        /// </summary>
        public static Vector2 InWorld(Vector2 worldScale)
        {
            var res = worldScale;
            res.Y *= -1;
            return Mouse.InScreenNormalized * res - res / 2;
        }

        /// <summary>
        /// Returns the current position of the mouse inside the world.
        /// </summary>
        public static Vector2 InWorld(Camera cam)
        {
            return InWorld(cam.WorldScale) + cam.Position;
        }

        /// <summary>
        /// Returns the current position of the mouse inside the world.
        /// </summary>
        public static Vector2 InWorld(Vector2 worldScale, Vector2 position)
        {
            return InWorld(worldScale) + position;
        }

        /// <summary>
        /// Checks if the mouse is over an object.
        /// </summary>
        /// <param name="mousePos">The position in the world. See <see cref="InWorld(Camera)"/></param>
        /// <param name="checkingObjects"></param>
        /// <typeparam name="TObject"></typeparam>
        public static bool MouseOver<TObject>(Vector2 mousePos, params TObject[] checkingObjects)
            where TObject : IModelItem, ITransformItem<Transformation>
            => MouseOver(mousePos, out _, checkingObjects);

        /// <summary>
        /// Checks if the mouse is over an object.
        /// </summary>
        /// <param name="mousePos">The position in the world. See <see cref="InWorld(Camera)"/></param>
        /// <param name="checkingObjects"></param>
        /// <typeparam name="TObject"></typeparam>
        /// <returns></returns>
        public static bool MouseOver<TObject>(Vector2 mousePos, ICollection<TObject> checkingObjects)
            where TObject : IModelItem, ITransformItem<Transformation>
            => MouseOver<TObject>(mousePos, out _, checkingObjects);

        /// <summary>
        /// Checks if the mouse is over an object and returns the object that was clicked on.
        /// </summary>
        /// <param name="mousePos">The position in the world. See <see cref="InWorld(Camera)"/></param>
        /// <param name="clicked"></param>
        /// <param name="checkingObjects"></param>
        /// <typeparam name="TObject"></typeparam>
        /// <returns></returns>
        public static bool MouseOver<TObject>(Vector2 mousePos, out TObject clicked, params TObject[] checkingObjects) 
            where TObject : IModelItem, ITransformItem<Transformation>
            => MouseOver<TObject>(mousePos, out clicked, (ICollection<TObject>)checkingObjects);

        /// <summary>
        /// Checks if the mouse is over an object and returns the object that was clicked on.
        /// </summary>
        /// <param name="mousePos">The position in the world. See <see cref="InWorld(Camera)"/></param>
        /// <param name="clickedObj"></param>
        /// <param name="checkingObjects"></param>
        /// <typeparam name="TObject"></typeparam>
        /// <returns></returns>
        public static bool MouseOver<TObject>(Vector2 mousePos, out TObject clickedObj, ICollection<TObject> checkingObjects)
            where TObject : IModelItem, ITransformItem<Transformation>
        {
            clickedObj = default;
            bool success = false;

            float distance = -10;

            foreach (TObject item in checkingObjects)
            {
                
                if (MouseOver(mousePos, item.Mesh.BoundingBox, item.Transform))
                {
                    Matrix4 worldPos = item.Transform.InWorldSpace;

                    // if z is greater than distance
                    if (worldPos[3, 2] > distance)
                    {
                        clickedObj = item;
                        distance = worldPos[3, 2];
                    }

                    success = true;
                }

            }
            

            return success;
        }

        /// <summary>
        /// Checks if the mouse is over an object and returns the object that was clicked on.
        /// </summary>
        /// <param name="mousePos">The position in the world. See <see cref="InWorld(Camera)"/></param>
        /// <param name="boundingBox"></param>
        /// <param name="transform"></param>
        /// <returns></returns>
        public static bool MouseOver(Vector2 mousePos, BoundingBox boundingBox, Transformation transform)
        {
            Matrix4 worldPos = transform.InWorldSpace;
            boundingBox.GetBounds(worldPos, out Vector3 min, out Vector3 max);

            if (mousePos.X > min.X && mousePos.X < max.X &&
                mousePos.Y > min.Y && mousePos.Y < max.Y)
            {
                return true;
            }
            return false;
        }
    }
}