//----------------------------------------------------------------------------------------------------------
// X-PostProcessing Library
// https://github.com/QianMo/X-PostProcessing-Library
// Copyright (C) 2020 QianMo. All rights reserved.
// Licensed under the MIT License 
// You may not use this file except in compliance with the License.You may obtain a copy of the License at
// http://opensource.org/licenses/MIT
//----------------------------------------------------------------------------------------------------------

//reference :https://docs.unity3d.com/550/Documentation/Manual/script-TiltShiftHdr.html

Shader "Hidden/X-PostProcessing/IrisBlur"
{
	HLSLINCLUDE
	
	#include "../../../Shaders/StdLib.hlsl"
	#include "../../../Shaders/XPostProcessing.hlsl"
	
	TEXTURE2D_SAMPLER2D(_BlurredTex, sampler_BlurredTex);

	float4 _BlurredTex_TexelSize;
	half2 _Params;	

	#define _BluSize _Params.x
	#define _BlurRadius _Params.y
	
	
	static const int DiscKernelSampleNum_LQ = 12;
	static const float2 DiscKernel_LQ[DiscKernelSampleNum_LQ] = 
	{
		float2(-0.326212, -0.40581),
		float2(-0.840144, -0.07358),
		float2(-0.695914, 0.457137),
		float2(-0.203345, 0.620716),
		float2(0.96234, -0.194983),
		float2(0.473434, -0.480026),
		float2(0.519456, 0.767022),
		float2(0.185461, -0.893124),
		float2(0.507431, 0.064425),
		float2(0.89642, 0.412458),
		float2(-0.32194, -0.932615),
		float2(-0.791559, -0.59771)
	};
	
	static const int DiscKernelSampleNum_HQ = 28;
	static const float3 DiscKernel_HQ[DiscKernelSampleNum_HQ] = 
	{
		float3(0.62463, 0.54337, 0.82790),
		float3(-0.13414, -0.94488, 0.95435),
		float3(0.38772, -0.43475, 0.58253),
		float3(0.12126, -0.19282, 0.22778),
		float3(-0.20388, 0.11133, 0.23230),
		float3(0.83114, -0.29218, 0.88100),
		float3(0.10759, -0.57839, 0.58831),
		float3(0.28285, 0.79036, 0.83945),
		float3(-0.36622, 0.39516, 0.53876),
		float3(0.75591, 0.21916, 0.78704),
		float3(-0.52610, 0.02386, 0.52664),
		float3(-0.88216, -0.24471, 0.91547),
		float3(-0.48888, -0.29330, 0.57011),
		float3(0.44014, -0.08558, 0.44838),
		float3(0.21179, 0.51373, 0.55567),
		float3(0.05483, 0.95701, 0.95858),
		float3(-0.59001, -0.70509, 0.91938),
		float3(-0.80065, 0.24631, 0.83768),
		float3(-0.19424, -0.18402, 0.26757),
		float3(-0.43667, 0.76751, 0.88304),
		float3(0.21666, 0.11602, 0.24577),
		float3(0.15696, -0.85600, 0.87027),
		float3(-0.75821, 0.58363, 0.95682),
		float3(0.99284, -0.02904, 0.99327),
		float3(-0.22234, -0.57907, 0.62029),
		float3(0.55052, -0.66984, 0.86704),
		float3(0.46431, 0.28115, 0.54280),
		float3(-0.07214, 0.60554, 0.60982),
	};
	
	
	float IrisMask(float2 uv)
	{
		float2 center = uv * 2 - 1;
		return dot(center, center) * (_BluSize * 0.001);
	}
	
	float4 FragIrisLQ(VaryingsDefault i): SV_Target
	{
		float4 screenColor = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord);
		float3 sum = screenColor.rgb;
		
		float mask = IrisMask(i.texcoord.xy);
		
		float4 poissonScale = (_BlurRadius * 30) * mask;
		
		for (int l = 0; l < DiscKernelSampleNum_LQ; l ++)
		{
			float2 sampleUV = i.texcoord.xy + DiscKernel_LQ[l].xy * poissonScale.xy;
			float3 sample0 = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, sampleUV.xy).rgb;
			float3 sample1 = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, sampleUV.xy).rgb;
			
			sum += sample0 + sample1;
		}
		
		return float4(sum.rgb / (1.0 + 2.0 * DiscKernelSampleNum_LQ), mask);
	}
	
	float4 FragIrisHQ(VaryingsDefault i): SV_Target
	{
		float4 screenColor = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord);
		float3 sum = screenColor.rgb;
		
		float mask = IrisMask(i.texcoord.xy);
		
		float4 poissonScale = (_BlurRadius * 30) * mask;

		for (int l = 0; l < DiscKernelSampleNum_HQ; l ++)
		{
			float2 sampleUV = i.texcoord.xy + DiscKernel_HQ[l].xy * poissonScale.xy;
			float3 sample0 = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, sampleUV.xy).rgb;
			float3 sample1 = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, sampleUV.xy).rgb;
			
			sum += sample0 + sample1;
		}
		
		return float4(sum.rgb / (1.0 + 2.0 * DiscKernelSampleNum_HQ), mask);
	}
	
	float4 FragBlend(VaryingsDefault i): SV_Target
	{
		float4 screenColor = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord);
		float4 blurredColor = SAMPLE_TEXTURE2D(_BlurredTex, sampler_BlurredTex, i.texcoord);
		
		float3 result = lerp(blurredColor.rgb, screenColor.rgb, saturate(blurredColor.a));
		
		return float4(result.rgb, screenColor.a);
	}
	
	
	ENDHLSL
	
	SubShader
	{
		Cull Off ZWrite Off ZTest Always
		
		//Pass 0 - Iris Blur High Quality
		Pass
		{
			HLSLPROGRAM
			
			#pragma vertex VertDefault
			#pragma fragment FragIrisHQ
			
			ENDHLSL
			
		}
		
		//Pass 1 - Iris Blur Low Quality
		Pass
		{
			HLSLPROGRAM
			
			#pragma vertex VertDefault
			#pragma fragment FragIrisLQ
			
			ENDHLSL
			
		}
		
		//Pass 2 - Blend
		Pass
		{
			HLSLPROGRAM
			
			#pragma vertex VertDefault
			#pragma fragment FragBlend
			
			ENDHLSL
			
		}
	}
}