//----------------------------------------------------------------------------------------------------------
// 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
//----------------------------------------------------------------------------------------------------------

Shader "Hidden/X-PostProcessing/Glitch/LineBlock"
{
	HLSLINCLUDE
	
	#include "../../../Shaders/StdLib.hlsl"
	#include "../../../Shaders/XPostProcessing.hlsl"
	
	#pragma shader_feature USING_FREQUENCY_INFINITE
	
	uniform half4 _Params;
	uniform half4 _Params2;
	
	#define _Frequency _Params.x
	#define _TimeX _Params.y
	#define _Amount _Params.z
	#define _Offset _Params2.x
	#define _LinesWidth _Params2.y
	#define _Alpha _Params2.z
	
	float randomNoise(float2 c)
	{
		return frac(sin(dot(c.xy, float2(12.9898, 78.233))) * 43758.5453);
	}
	
	float trunc(float x, float num_levels)
	{
		return floor(x * num_levels) / num_levels;
	}
	
	float2 trunc(float2 x, float2 num_levels)
	{
		return floor(x * num_levels) / num_levels;
	}
	
	float3 rgb2yuv(float3 rgb)
	{
		float3 yuv;
		yuv.x = dot(rgb, float3(0.299, 0.587, 0.114));
		yuv.y = dot(rgb, float3(-0.14713, -0.28886, 0.436));
		yuv.z = dot(rgb, float3(0.615, -0.51499, -0.10001));
		return yuv;
	}
	
	float3 yuv2rgb(float3 yuv)
	{
		float3 rgb;
		rgb.r = yuv.x + yuv.z * 1.13983;
		rgb.g = yuv.x + dot(float2(-0.39465, -0.58060), yuv.yz);
		rgb.b = yuv.x + yuv.y * 2.03211;
		return rgb;
	}
	
	
	float4 Frag_Horizontal(VaryingsDefault i): SV_Target
	{
		float2 uv = i.texcoord;
		
		half strength = 0;
		#if USING_FREQUENCY_INFINITE
			strength = 10;
		#else
			strength = 0.5 + 0.5 * cos(_TimeX * _Frequency);
		#endif
		
		_TimeX *= strength;
		
		//	[1] 生成随机强度梯度线条
		float truncTime = trunc(_TimeX, 4.0);
		float uv_trunc = randomNoise(trunc(uv.yy, float2(8, 8)) + 100.0 * truncTime);
		float uv_randomTrunc = 6.0 * trunc(_TimeX, 24.0 * uv_trunc);
		
		// [2] 生成随机非均匀宽度线条
		float blockLine_random = 0.5 * randomNoise(trunc(uv.yy + uv_randomTrunc, float2(8 * _LinesWidth, 8 * _LinesWidth)));
		blockLine_random += 0.5 * randomNoise(trunc(uv.yy + uv_randomTrunc, float2(7, 7)));
		blockLine_random = blockLine_random * 2.0 - 1.0;
		blockLine_random = sign(blockLine_random) * saturate((abs(blockLine_random) - _Amount) / (0.4));
		blockLine_random = lerp(0, blockLine_random, _Offset);
		
		
		// [3] 生成源色调的blockLine Glitch
		float2 uv_blockLine = uv;
		uv_blockLine = saturate(uv_blockLine + float2(0.1 * blockLine_random, 0));
		float4 blockLineColor = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, abs(uv_blockLine));
		
		// [4] 将RGB转到YUV空间，并做色调偏移
		// RGB -> YUV
		float3 blockLineColor_yuv = rgb2yuv(blockLineColor.rgb);
		// adjust Chrominance | 色度
		blockLineColor_yuv.y /= 1.0 - 3.0 * abs(blockLine_random) * saturate(0.5 - blockLine_random);
		// adjust Chroma | 浓度
		blockLineColor_yuv.z += 0.125 * blockLine_random * saturate(blockLine_random - 0.5);
		float3 blockLineColor_rgb = yuv2rgb(blockLineColor_yuv);
		
		
		// [5] 与源场景图进行混合
		float4 sceneColor = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord);
		return lerp(sceneColor, float4(blockLineColor_rgb, blockLineColor.a), _Alpha);
	}
	
	float4 Frag_Vertical(VaryingsDefault i): SV_Target
	{
		float2 uv = i.texcoord;
		
		half strength = 0;
		#if USING_FREQUENCY_INFINITE
			strength = 10;
		#else
			strength = 0.5 + 0.5 * cos(_TimeX * _Frequency);
		#endif
		
		_TimeX *= strength;
		
		// [1] 生成随机均匀宽度线条
		float truncTime = trunc(_TimeX, 4.0);
		float uv_trunc = randomNoise(trunc(uv.xx, float2(8, 8)) + 100.0 * truncTime);
		float uv_randomTrunc = 6.0 * trunc(_TimeX, 24.0 * uv_trunc);
		
		// [2] 生成随机非均匀宽度线条 | Generate Random inhomogeneous Block Line
		float blockLine_random = 0.5 * randomNoise(trunc(uv.xx + uv_randomTrunc, float2(8 * _LinesWidth, 8 * _LinesWidth)));
		blockLine_random += 0.5 * randomNoise(trunc(uv.xx + uv_randomTrunc, float2(7, 7)));
		blockLine_random = blockLine_random * 2.0 - 1.0;
		blockLine_random = sign(blockLine_random) * saturate((abs(blockLine_random) - _Amount) / (0.4));
		blockLine_random = lerp(0, blockLine_random, _Offset);
		
		// [3] 生成源色调的blockLine Glitch
		float2 uv_blockLine = uv;
		uv_blockLine = saturate(uv_blockLine + float2(0, 0.1 * blockLine_random));
		float4 blockLineColor = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, abs(uv_blockLine));
		
		// [4] 将RGB转到YUV空间，并做色调偏移
		// RGB -> YUV
		float3 blockLineColor_yuv = rgb2yuv(blockLineColor.rgb);
		// adjust Chrominance | 色度
		blockLineColor_yuv.y /= 1.0 - 3.0 * abs(blockLine_random) * saturate(0.5 - blockLine_random);
		// adjust Chroma | 浓度
		blockLineColor_yuv.z += 0.125 * blockLine_random * saturate(blockLine_random - 0.5);
		float3 blockLineColor_rgb = yuv2rgb(blockLineColor_yuv);
		
		// [5] 与源场景图进行混合
		float4 sceneColor = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord);
		return lerp(sceneColor, float4(blockLineColor_rgb, blockLineColor.a), _Alpha);
	}
	
	
	ENDHLSL
	
	SubShader
	{
		Cull Off ZWrite Off ZTest Always
		
		Pass
		{
			HLSLPROGRAM
			
			#pragma vertex VertDefault
			#pragma fragment Frag_Horizontal
			
			ENDHLSL
			
		}
		
		Pass
		{
			HLSLPROGRAM
			
			#pragma vertex VertDefault
			#pragma fragment Frag_Vertical
			
			ENDHLSL
			
		}
	}
}