Shader "Enviro/Standard/Blit"
{
	Properties
	{
	//	_MainTex("Base (RGB)", any) = "white" {}
		_CloudsTex("Clouds (RGB)", any) = "white" {}
	}
		SubShader
	{
		Pass
	{
		Cull Off
		ZWrite Off
		Ztest LEqual

		CGPROGRAM

	#pragma vertex vert
	#pragma fragment frag
	#include "UnityCG.cginc"
	#pragma exclude_renderers gles 
	#pragma multi_compile __ ENVIRO_DEPTHBLENDING
	#pragma multi_compile __ ENVIROURP
	
	UNITY_DECLARE_SCREENSPACE_TEXTURE(_MainTex);
	uniform half4 _MainTex_ST;
	uniform half4 _MainTex_TexelSize;
	UNITY_DECLARE_DEPTH_TEXTURE(_CameraDepthTexture);
	uniform half4 _CameraDepthTexture_ST;

	uniform UNITY_DECLARE_SCREENSPACE_TEXTURE(_SubFrame);
	uniform half4 _SubFrame_ST;
	uniform UNITY_DECLARE_SCREENSPACE_TEXTURE(_PrevFrame);
	uniform half4 _PrevFrame_ST;

	uniform float4x4 _Projection;
	uniform float4x4 _ProjectionSPVR;
	uniform float4x4 _InverseProjection;
	uniform float4x4 _InverseProjectionSPVR;

	uniform float4x4 _InverseRotation;
	uniform float4x4 _InverseRotationSPVR;

	uniform float4x4 _PreviousRotation;
	uniform float4x4 _PreviousRotationSPVR;

	uniform float _FrameNumber;
	uniform float _ReprojectionPixelSize;

	uniform float2 _SubFrameDimension;
	uniform float2 _FrameDimension;


	struct v2f {
		float4 position : SV_POSITION;
		float2 uv : TEXCOORD0;
		float2 uv1 : TEXCOORD1;

		UNITY_VERTEX_OUTPUT_STEREO
	};

	v2f vert(appdata_img v)
	{
		v2f o;

		UNITY_SETUP_INSTANCE_ID(v); //Insert
		UNITY_INITIALIZE_OUTPUT(v2f, o); //Insert
		UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o); //Insert
#if defined(ENVIROURP)
	o.position = float4(v.vertex.xyz,1.0);
#if UNITY_UV_STARTS_AT_TOP
    o.position.y *= -1;
#endif
#else
	o.position = UnityObjectToClipPos(v.vertex);
#endif
	
		o.uv = v.texcoord;

#if UNITY_UV_STARTS_AT_TOP
		o.uv1 = v.texcoord.xy;
		if (_MainTex_TexelSize.y < 0)
			o.uv1.y = 1 - o.uv1.y;
#endif	
 
		return o;
	}

	float4 frag(v2f i) : COLOR
	{
		UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(i);

#if UNITY_UV_STARTS_AT_TOP
	float4 main = UNITY_SAMPLE_SCREENSPACE_TEXTURE(_MainTex, UnityStereoScreenSpaceUVAdjust(i.uv1, _MainTex_ST));
#else
	float4 main = UNITY_SAMPLE_SCREENSPACE_TEXTURE(_MainTex, UnityStereoScreenSpaceUVAdjust(i.uv, _MainTex_ST));
#endif

	float4 final = main;


#ifndef ENVIRO_DEPTHBLENDING

#if UNITY_UV_STARTS_AT_TOP
	float depthSample = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, i.uv1.xy);
#else 
	float depthSample = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, i.uv.xy);
#endif

	depthSample = Linear01Depth(depthSample);

	if (depthSample > 0.9999)
	{
#endif

		float2 uv = (floor(i.uv * _FrameDimension) + 0.5) / _FrameDimension;
		float2 uv2 = (floor(i.uv * _SubFrameDimension) + 0.5) / _SubFrameDimension;

		float x = fmod(uv.x, _ReprojectionPixelSize);
		float y = fmod(uv.y, _ReprojectionPixelSize);
		float currentFrame = y * _ReprojectionPixelSize + x;

		float4 cloud;

		if (currentFrame == _FrameNumber) 
		{
			cloud = UNITY_SAMPLE_SCREENSPACE_TEXTURE(_SubFrame, UnityStereoScreenSpaceUVAdjust(uv2, _MainTex_ST));
		}
		else
		{
			float4 reprojection;
			float4 pos = float4(i.uv * 2.0 - 1.0, 1.0, 1.0);

			if (unity_StereoEyeIndex == 0)
			{
				pos = mul(_InverseProjection, pos);
				pos = pos / pos.w;
				pos.xyz = mul((float3x3)_InverseRotation, pos.xyz);
				pos.xyz = mul((float3x3)_PreviousRotation, pos.xyz);

				reprojection = mul(_Projection, pos);
			}
			else
			{
				pos = mul(_InverseProjectionSPVR, pos);
				pos = pos / pos.w;
				pos.xyz = mul((float3x3)_InverseRotationSPVR, pos.xyz);
				pos.xyz = mul((float3x3)_PreviousRotationSPVR, pos.xyz);

				reprojection = mul(_ProjectionSPVR, pos);
			}

			if (reprojection.y < 0.0 || reprojection.y > 1.0 || reprojection.x < 0.0 || reprojection.x > 1.0)
			{
				cloud = UNITY_SAMPLE_SCREENSPACE_TEXTURE(_SubFrame, UnityStereoScreenSpaceUVAdjust(i.uv, _MainTex_ST));
			}
			else
			{ 
				cloud = UNITY_SAMPLE_SCREENSPACE_TEXTURE(_PrevFrame, UnityStereoScreenSpaceUVAdjust(reprojection.xy, _MainTex_ST));
			}
		}

		final = float4 (main * (1 - cloud.a) + cloud.rgb * cloud.a, 1.0);

#ifndef ENVIRO_DEPTHBLENDING
	}
#endif
	return final;
	}

		ENDCG
	}
	}
}