using System.Collections;
using UnityEngine;

public class ReflectionCamera : MonoBehaviour
{
	public float m_ClipPlaneOffset = 0.07f;

	public LayerMask CullingMask = -17;

	public bool HDR;

	public bool OcclusionCulling = true;

	public float TextureScale = 1f;

	public RenderTextureFormat RenderTextureFormat;

	public FilterMode FilterMode;

	public RenderingPath RenderingPath;

	public bool UseRealtimeUpdate;

	public int FPSWhenMoveCamera = 40;

	public int FPSWhenStaticCamera = 20;

	private RenderTexture renderTexture;

	private GameObject go;

	private Camera reflectionCamera;

	private Vector3 oldPosition;

	private Quaternion oldRotation;

	private Transform instanceCameraTransform;

	private int frameCountWhenCameraIsStatic;

	private bool canUpdateCamera;

	private bool isStaticUpdate;

	private WaitForSeconds fpsMove;

	private WaitForSeconds fpsStatic;

	private const int DropedFrames = 50;

	private Camera currentCamera;

	private void OnEnable()
	{
		Shader.EnableKeyword("editor_off");
		Shader.EnableKeyword("cubeMap_off");
		currentCamera = Camera.main;
		fpsMove = new WaitForSeconds(1f / (float)FPSWhenMoveCamera);
		fpsStatic = new WaitForSeconds(1f / (float)FPSWhenStaticCamera);
		if (!UseRealtimeUpdate)
		{
			StartCoroutine(RepeatCameraMove());
			StartCoroutine(RepeatCameraStatic());
		}
		else
		{
			canUpdateCamera = true;
		}
	}

	private IEnumerator RepeatCameraMove()
	{
		while (true)
		{
			if (!isStaticUpdate)
			{
				canUpdateCamera = true;
			}
			yield return fpsMove;
		}
	}

	private IEnumerator RepeatCameraStatic()
	{
		while (true)
		{
			if (isStaticUpdate)
			{
				canUpdateCamera = true;
			}
			yield return fpsStatic;
		}
	}

	private void OnBecameVisible()
	{
		if (go != null)
		{
			go.SetActive(true);
		}
	}

	private void OnBecameInvisible()
	{
	}

	private void Update()
	{
		Vector3 position = base.transform.position;
		Vector3 up = base.transform.up;
		float w = 0f - Vector3.Dot(up, position) - m_ClipPlaneOffset;
		Vector4 plane = new Vector4(up.x, up.y, up.z, w);
		Matrix4x4 reflectionMat = Matrix4x4.zero;
		CalculateReflectionMatrix(ref reflectionMat, plane);
		Vector3 position2 = currentCamera.transform.position;
		Vector3 position3 = reflectionMat.MultiplyPoint(position2);
		if (go == null)
		{
			renderTexture = new RenderTexture((int)((float)Screen.width * TextureScale), (int)((float)Screen.height * TextureScale), 16, RenderTextureFormat);
			renderTexture.DiscardContents();
			go = new GameObject("Water Refl Camera");
			reflectionCamera = go.AddComponent<Camera>();
			reflectionCamera.depth = currentCamera.depth - 1f;
			reflectionCamera.renderingPath = RenderingPath;
			reflectionCamera.depthTextureMode = DepthTextureMode.None;
			go.transform.position = base.transform.position;
			go.transform.rotation = base.transform.rotation;
			reflectionCamera.cullingMask = CullingMask;
			reflectionCamera.targetTexture = renderTexture;
			reflectionCamera.hdr = HDR;
			reflectionCamera.useOcclusionCulling = OcclusionCulling;
			Shader.SetGlobalTexture("_ReflectionTex", renderTexture);
			instanceCameraTransform = reflectionCamera.transform;
		}
		reflectionCamera.worldToCameraMatrix = currentCamera.worldToCameraMatrix * reflectionMat;
		Vector4 clipPlane = CameraSpacePlane(reflectionCamera, position, up, 1f);
		reflectionCamera.projectionMatrix = currentCamera.CalculateObliqueMatrix(clipPlane);
		GL.invertCulling = true;
		go.transform.position = position3;
		Vector3 eulerAngles = currentCamera.transform.eulerAngles;
		go.transform.eulerAngles = new Vector3(0f - eulerAngles.x, eulerAngles.y, eulerAngles.z);
		UpdateCameraPosition();
		GL.invertCulling = false;
	}

	private void UpdateCameraPosition()
	{
		if (reflectionCamera == null)
		{
			return;
		}
		if (Vector3.SqrMagnitude(instanceCameraTransform.position - oldPosition) <= 1E-05f && instanceCameraTransform.rotation == oldRotation)
		{
			frameCountWhenCameraIsStatic++;
			if (frameCountWhenCameraIsStatic >= 50)
			{
				isStaticUpdate = true;
			}
		}
		else
		{
			frameCountWhenCameraIsStatic = 0;
			isStaticUpdate = false;
		}
		oldPosition = instanceCameraTransform.position;
		oldRotation = instanceCameraTransform.rotation;
		if (canUpdateCamera)
		{
			reflectionCamera.enabled = true;
			if (!UseRealtimeUpdate)
			{
				canUpdateCamera = false;
			}
		}
		else if (reflectionCamera.enabled)
		{
			reflectionCamera.enabled = false;
		}
	}

	private static float sgn(float a)
	{
		if (a > 0f)
		{
			return 1f;
		}
		if (a < 0f)
		{
			return -1f;
		}
		return 0f;
	}

	private Matrix4x4 CalculateObliqueMatrix(Matrix4x4 projection, Vector4 clipPlane)
	{
		Vector4 b = projection.inverse * new Vector4(sgn(clipPlane.x), sgn(clipPlane.y), 1f, 1f);
		Vector4 vector = clipPlane * (2f / Vector4.Dot(clipPlane, b));
		projection[2] = vector.x - projection[3];
		projection[6] = vector.y - projection[7];
		projection[10] = vector.z - projection[11];
		projection[14] = vector.w - projection[15];
		return projection;
	}

	private static void CalculateReflectionMatrix(ref Matrix4x4 reflectionMat, Vector4 plane)
	{
		reflectionMat.m00 = 1f - 2f * plane[0] * plane[0];
		reflectionMat.m01 = -2f * plane[0] * plane[1];
		reflectionMat.m02 = -2f * plane[0] * plane[2];
		reflectionMat.m03 = -2f * plane[3] * plane[0];
		reflectionMat.m10 = -2f * plane[1] * plane[0];
		reflectionMat.m11 = 1f - 2f * plane[1] * plane[1];
		reflectionMat.m12 = -2f * plane[1] * plane[2];
		reflectionMat.m13 = -2f * plane[3] * plane[1];
		reflectionMat.m20 = -2f * plane[2] * plane[0];
		reflectionMat.m21 = -2f * plane[2] * plane[1];
		reflectionMat.m22 = 1f - 2f * plane[2] * plane[2];
		reflectionMat.m23 = -2f * plane[3] * plane[2];
		reflectionMat.m30 = 0f;
		reflectionMat.m31 = 0f;
		reflectionMat.m32 = 0f;
		reflectionMat.m33 = 1f;
	}

	private Vector4 CameraSpacePlane(Camera cam, Vector3 pos, Vector3 normal, float sideSign)
	{
		Vector3 point = pos + normal * m_ClipPlaneOffset;
		Matrix4x4 worldToCameraMatrix = cam.worldToCameraMatrix;
		Vector3 lhs = worldToCameraMatrix.MultiplyPoint(point);
		Vector3 rhs = worldToCameraMatrix.MultiplyVector(normal).normalized * sideSign;
		return new Vector4(rhs.x, rhs.y, rhs.z, 0f - Vector3.Dot(lhs, rhs));
	}

	private void OnDisable()
	{
		ClearCamera();
		Shader.DisableKeyword("editor_off");
		Shader.DisableKeyword("cubeMap_off");
	}

	private void ClearCamera()
	{
		if ((bool)go)
		{
			Object.DestroyImmediate(go);
			go = null;
		}
		if ((bool)renderTexture)
		{
			Object.DestroyImmediate(renderTexture);
			renderTexture = null;
		}
	}
}