HeavenStudio/Assets/Plugins/Starpelly/RendererExtensions.cs
2022-01-12 22:59:54 -05:00

62 lines
3.1 KiB
C#

using UnityEngine;
public static class RendererExtensions
{
/// <summary>
/// Counts the bounding box corners of the given RectTransform that are visible from the given Camera in screen space.
/// </summary>
/// <returns>The amount of bounding box corners that are visible from the Camera.</returns>
/// <param name="rectTransform">Rect transform.</param>
/// <param name="camera">Camera.</param>
private static int CountCornersVisibleFrom(this RectTransform rectTransform, Camera camera)
{
Rect screenBounds = new Rect(0f, 0f, Screen.width, Screen.height); // Screen space bounds (assumes camera renders across the entire screen)
Vector3[] objectCorners = new Vector3[4];
rectTransform.GetWorldCorners(objectCorners);
int visibleCorners = 0;
Vector3 tempScreenSpaceCorner; // Cached
for (var i = 0; i < objectCorners.Length; i++) // For each corner in rectTransform
{
tempScreenSpaceCorner = camera.WorldToScreenPoint(objectCorners[i]); // Transform world space position of corner to screen space
if (screenBounds.Contains(tempScreenSpaceCorner)) // If the corner is inside the screen
{
visibleCorners++;
}
}
return visibleCorners;
}
/// <summary>
/// Determines if this RectTransform is fully visible from the specified camera.
/// Works by checking if each bounding box corner of this RectTransform is inside the cameras screen space view frustrum.
/// </summary>
/// <returns><c>true</c> if is fully visible from the specified camera; otherwise, <c>false</c>.</returns>
/// <param name="rectTransform">Rect transform.</param>
/// <param name="camera">Camera.</param>
public static bool IsFullyVisibleFrom(this RectTransform rectTransform, Camera camera)
{
return CountCornersVisibleFrom(rectTransform, camera) == 4; // True if all 4 corners are visible
}
/// <summary>
/// Determines if this RectTransform is at least partially visible from the specified camera.
/// Works by checking if any bounding box corner of this RectTransform is inside the cameras screen space view frustrum.
/// </summary>
/// <returns><c>true</c> if is at least partially visible from the specified camera; otherwise, <c>false</c>.</returns>
/// <param name="rectTransform">Rect transform.</param>
/// <param name="camera">Camera.</param>
public static bool IsVisibleFrom(this RectTransform rectTransform, Camera camera)
{
return CountCornersVisibleFrom(rectTransform, camera) > 0; // True if any corners are visible
}
public static bool MouseIsWithin(this RectTransform rectTransform)
{
var normalizedMousePosition = new Vector2(Input.mousePosition.x / Screen.width, Input.mousePosition.y / Screen.height);
return normalizedMousePosition.x > rectTransform.anchorMin.x &&
normalizedMousePosition.x < rectTransform.anchorMax.x &&
normalizedMousePosition.y > rectTransform.anchorMin.y &&
normalizedMousePosition.y < rectTransform.anchorMax.y;
}
}