using System;
using UnityEngine;

namespace UnityStandardAssets.ImageEffects
{
	[ExecuteInEditMode]
	[RequireComponent(typeof(Camera))]
	[AddComponentMenu("Image Effects/Rendering/Screen Space Ambient Occlusion")]
	public class ScreenSpaceAmbientOcclusion : MonoBehaviour
	{
		public enum SSAOSamples
		{
			Low = 0,
			Medium = 1,
			High = 2
		}

		public float m_Radius = 0.4f;

		public SSAOSamples m_SampleCount = SSAOSamples.Medium;

		public float m_OcclusionIntensity = 1.5f;

		public int m_Blur = 2;

		public int m_Downsampling = 2;

		public float m_OcclusionAttenuation = 1f;

		public float m_MinZ = 0.01f;

		public Shader m_SSAOShader;

		private Material m_SSAOMaterial;

		public Texture2D m_RandomTexture;

		private bool m_Supported;

		private static Material CreateMaterial(Shader shader)
		{
			if (!shader)
			{
				return null;
			}
			return new Material(shader)
			{
				hideFlags = HideFlags.HideAndDontSave
			};
		}

		private static void DestroyMaterial(Material mat)
		{
			if ((bool)mat)
			{
				UnityEngine.Object.DestroyImmediate(mat);
				mat = null;
			}
		}

		private void OnDisable()
		{
			DestroyMaterial(m_SSAOMaterial);
		}

		private void Start()
		{
			if (!SystemInfo.supportsImageEffects || !SystemInfo.SupportsRenderTextureFormat(RenderTextureFormat.Depth))
			{
				m_Supported = false;
				base.enabled = false;
				return;
			}
			CreateMaterials();
			if (!m_SSAOMaterial || m_SSAOMaterial.passCount != 5)
			{
				m_Supported = false;
				base.enabled = false;
			}
			else
			{
				m_Supported = true;
			}
		}

		private void OnEnable()
		{
			GetComponent<Camera>().depthTextureMode |= DepthTextureMode.DepthNormals;
		}

		private void CreateMaterials()
		{
			if (!m_SSAOMaterial && m_SSAOShader.isSupported)
			{
				m_SSAOMaterial = CreateMaterial(m_SSAOShader);
				m_SSAOMaterial.SetTexture("_RandomTexture", m_RandomTexture);
			}
		}

		[ImageEffectOpaque]
		private void OnRenderImage(RenderTexture source, RenderTexture destination)
		{
			if (!m_Supported || !m_SSAOShader.isSupported)
			{
				base.enabled = false;
				return;
			}
			CreateMaterials();
			m_Downsampling = Mathf.Clamp(m_Downsampling, 1, 6);
			m_Radius = Mathf.Clamp(m_Radius, 0.05f, 1f);
			m_MinZ = Mathf.Clamp(m_MinZ, 1E-05f, 0.5f);
			m_OcclusionIntensity = Mathf.Clamp(m_OcclusionIntensity, 0.5f, 4f);
			m_OcclusionAttenuation = Mathf.Clamp(m_OcclusionAttenuation, 0.2f, 2f);
			m_Blur = Mathf.Clamp(m_Blur, 0, 4);
			RenderTexture renderTexture = RenderTexture.GetTemporary(source.width / m_Downsampling, source.height / m_Downsampling, 0);
			float fieldOfView = GetComponent<Camera>().fieldOfView;
			float farClipPlane = GetComponent<Camera>().farClipPlane;
			float num = Mathf.Tan(fieldOfView * (MathF.PI / 180f) * 0.5f) * farClipPlane;
			float x = num * GetComponent<Camera>().aspect;
			m_SSAOMaterial.SetVector("_FarCorner", new Vector3(x, num, farClipPlane));
			int num2;
			int num3;
			if ((bool)m_RandomTexture)
			{
				num2 = m_RandomTexture.width;
				num3 = m_RandomTexture.height;
			}
			else
			{
				num2 = 1;
				num3 = 1;
			}
			m_SSAOMaterial.SetVector("_NoiseScale", new Vector3((float)renderTexture.width / (float)num2, (float)renderTexture.height / (float)num3, 0f));
			m_SSAOMaterial.SetVector("_Params", new Vector4(m_Radius, m_MinZ, 1f / m_OcclusionAttenuation, m_OcclusionIntensity));
			bool num4 = m_Blur > 0;
			Graphics.Blit(num4 ? null : source, renderTexture, m_SSAOMaterial, (int)m_SampleCount);
			if (num4)
			{
				RenderTexture temporary = RenderTexture.GetTemporary(source.width, source.height, 0);
				m_SSAOMaterial.SetVector("_TexelOffsetScale", new Vector4((float)m_Blur / (float)source.width, 0f, 0f, 0f));
				m_SSAOMaterial.SetTexture("_SSAO", renderTexture);
				Graphics.Blit(null, temporary, m_SSAOMaterial, 3);
				RenderTexture.ReleaseTemporary(renderTexture);
				RenderTexture temporary2 = RenderTexture.GetTemporary(source.width, source.height, 0);
				m_SSAOMaterial.SetVector("_TexelOffsetScale", new Vector4(0f, (float)m_Blur / (float)source.height, 0f, 0f));
				m_SSAOMaterial.SetTexture("_SSAO", temporary);
				Graphics.Blit(source, temporary2, m_SSAOMaterial, 3);
				RenderTexture.ReleaseTemporary(temporary);
				renderTexture = temporary2;
			}
			m_SSAOMaterial.SetTexture("_SSAO", renderTexture);
			Graphics.Blit(source, destination, m_SSAOMaterial, 4);
			RenderTexture.ReleaseTemporary(renderTexture);
		}
	}
}