/*

* @author Valentin Simonov / http://va.lent.in/

*/

using UnityEngine;

namespace TouchScript.Utils

{

/// <summary>

/// Projection utils.

/// </summary>

public static class ProjectionUtils

{

/// <summary>

/// Projects a screen point to a plane from a camera's point of view.

/// </summary>

/// <param name="position">Screen point.</param>

/// <param name="camera">The camera.</param>

/// <param name="projectionPlane">Projection plane.</param>

/// <returns>Projected point on the plane in World coordinates.</returns>

public static Vector3 CameraToPlaneProjection(Vector2 position, Camera camera, Plane projectionPlane)

{

var distance = 0f;

var ray = camera.ScreenPointToRay(position);

var result = projectionPlane.Raycast(ray, out distance);

if (!result && distance == 0f) return -projectionPlane.normal * projectionPlane.GetDistanceToPoint(Vector3.zero); // perpendicular to the screen

return ray.origin + ray.direction * distance;

}

/// <summary>

/// Projects a screen point to a plane using parallel projection.

/// </summary>

/// <param name="position">Screen point.</param>

/// <param name="projectionPlane">Projection plane.</param>

/// <returns>Projected point on the plane in World coordinates.</returns>

public static Vector3 ScreenToPlaneProjection(Vector2 position, Plane projectionPlane)

{

var distance = 0f;

var ray = new Ray(position, Vector3.forward);

var result = projectionPlane.Raycast(ray, out distance);

if (!result && distance == 0f) return -projectionPlane.normal * projectionPlane.GetDistanceToPoint(Vector3.zero); // perpendicular to the screen

return ray.origin + new Vector3(0, 0, distance);

}

}

}