using System;
using UnityEngine;

namespace Artngame.SKYMASTER
{
	public static class CameraExtension
	{
		public static Vector4 GetProjectionExtents(this Camera camera)
		{
			return camera.GetProjectionExtents(0f, 0f);
		}

		public static Vector4 GetProjectionExtents(this Camera camera, float texelOffsetX, float texelOffsetY)
		{
			if (camera == null)
			{
				return Vector4.zero;
			}
			float num = (camera.orthographic ? camera.orthographicSize : Mathf.Tan(MathF.PI / 360f * camera.fieldOfView));
			float num2 = num * camera.aspect;
			float num3 = num2 / (0.5f * (float)camera.pixelWidth);
			float num4 = num / (0.5f * (float)camera.pixelHeight);
			float z = num3 * texelOffsetX;
			float w = num4 * texelOffsetY;
			return new Vector4(num2, num, z, w);
		}

		public static Vector4 GetProjectionExtents(this Camera camera, Camera.StereoscopicEye eye)
		{
			return camera.GetProjectionExtents(eye, 0f, 0f);
		}

		public static Vector4 GetProjectionExtents(this Camera camera, Camera.StereoscopicEye eye, float texelOffsetX, float texelOffsetY)
		{
			Matrix4x4 matrix4x = Matrix4x4.Inverse(camera.GetStereoProjectionMatrix(eye));
			Vector3 vector = matrix4x.MultiplyPoint3x4(new Vector3(-1f, -1f, 0.95f));
			Vector3 vector2 = matrix4x.MultiplyPoint3x4(new Vector3(1f, 1f, 0.95f));
			vector /= 0f - vector.z;
			vector2 /= 0f - vector2.z;
			float num = 0.5f * (vector2.x - vector.x);
			float num2 = 0.5f * (vector2.y - vector.y);
			float num3 = num / (0.5f * (float)camera.pixelWidth);
			float num4 = num2 / (0.5f * (float)camera.pixelHeight);
			float z = 0.5f * (vector2.x + vector.x) + num3 * texelOffsetX;
			float w = 0.5f * (vector2.y + vector.y) + num4 * texelOffsetY;
			return new Vector4(num, num2, z, w);
		}

		public static Matrix4x4 GetProjectionMatrix(this Camera camera)
		{
			return camera.GetProjectionMatrix(0f, 0f);
		}

		public static Matrix4x4 GetProjectionMatrix(this Camera camera, float texelOffsetX, float texelOffsetY)
		{
			if (camera == null)
			{
				return Matrix4x4.identity;
			}
			Vector4 projectionExtents = camera.GetProjectionExtents(texelOffsetX, texelOffsetY);
			float farClipPlane = camera.farClipPlane;
			float nearClipPlane = camera.nearClipPlane;
			float num = projectionExtents.z - projectionExtents.x;
			float num2 = projectionExtents.z + projectionExtents.x;
			float num3 = projectionExtents.w - projectionExtents.y;
			float num4 = projectionExtents.w + projectionExtents.y;
			if (camera.orthographic)
			{
				return Matrix4x4Extension.GetOrthographicProjection(num, num2, num3, num4, nearClipPlane, farClipPlane);
			}
			return Matrix4x4Extension.GetPerspectiveProjection(num * nearClipPlane, num2 * nearClipPlane, num3 * nearClipPlane, num4 * nearClipPlane, nearClipPlane, farClipPlane);
		}
	}
}