//----------------------------------------------------------------------------------------------------------
// 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/PixelizeLed"
{
	SubShader
	{
		Cull Off ZWrite Off ZTest Always

		Pass
		{
			HLSLPROGRAM

			#pragma vertex VertDefault
			#pragma fragment Frag

			#include "../../../Shaders/StdLib.hlsl"
			#include "../../../Shaders/XPostProcessing.hlsl"

			
			half4 _Params;
			half4 _BackgroundColor;

			#define _PixelSize _Params.x
			#define _PixelRatio _Params.y
			#define _LedRadius _Params.z

			float2 RectPixelizeUV(half2 uv)
			{
				float pixelScale = 1.0 / _PixelSize;
				//除以缩放系数，在向上取整，再乘以缩放系数，得到分段UV
				float2 coord = half2(pixelScale * floor(uv.x / (pixelScale)), (pixelScale * _PixelRatio ) * floor(uv.y / (pixelScale *_PixelRatio)));

				return  coord;
			}



			float4 Frag(VaryingsDefault i) : SV_Target
			{

				// 实现矩形像素效果
				float2 uv = RectPixelizeUV(i.texcoord);
				float4 color = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, uv);

				// 计算矩形像素坐标
				half2 coord = i.texcoord * half2(_PixelSize, _PixelSize / _PixelRatio);

				// 横纵坐标强度渐变
				half ledX = abs(sin(coord.x * 3.1415)) * 1.5;
				half ledY = abs(sin(coord.y * 3.1415)) * 1.5;
				// 求解LedValue
				half ledValue = ledX * ledY;
				// led半径校正
				half radius = step(ledValue, _LedRadius);

				//最终颜色 = 基础led颜色 + 渐变led颜色 + 背景颜色
				color = ((1 - radius) * color) + ((color * ledValue) * radius) + radius * (1- ledValue)* _BackgroundColor;


				return color;

			}

			ENDHLSL

		}
	}
}