Shader "YXJ/Particles/DistortionBase" 
{
	Properties 
	{
		_TintColor("Tint Color",color) = (1,1,1,1)
		_MaskTex("Mask Tex (A)", 2D) = "white" {}
		_NoiseTex("Noise Texture (RG)", 2D) = "white" {}
		_HeatTime("Heat Time", range(0,1.5)) = 1
		_HeatForce("Heat Force", range(0,5)) = 0.1
	}

	SubShader
	{
		Tags{ "Queue" = "Transparent+100" "IgnoreProjector" = "True"  "RenderType" = "Transparent" "LightMode" = "Grab_YXJ"}
		Cull Off Lighting Off ZWrite Off
		Pass 
		{
			Blend SrcAlpha OneMinusSrcAlpha
			AlphaTest Greater .01
			HLSLPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#pragma fragmentoption ARB_precision_hint_fastest

			#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
			#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"

			struct appdata_t
			{
				float4 vertex : POSITION;
				float4 color : COLOR;
				float2 texcoord: TEXCOORD0;
			};

			struct v2f 
			{
				float4 vertex : POSITION;
				float4 color : COLOR;
				float2 uvMask : TEXCOORD0;
				float4 uvGrab : TEXCOORD1;					
			};


			sampler2D _MaskTex; float4 _MaskTex_ST;
			sampler2D _NoiseTex; float4 _NoiseTex_ST;
			float4 _TintColor;
			half _HeatTime;
			half _HeatForce;
			SAMPLER(_CameraTransparentTexture);


			v2f vert (appdata_t v)
			{
				v2f o;
				VertexPositionInputs vertexInput = GetVertexPositionInputs(v.vertex.xyz);
				o.vertex = vertexInput.positionCS;
				o.color = v.color;
				o.uvMask = TRANSFORM_TEX(v.texcoord, _MaskTex);
				#if UNITY_UV_STARTS_AT_TOP
					float scale = -1.0;
				#else
					float scale = 1.0;
				#endif

				o.uvGrab.xy = (float2(o.vertex.x, o.vertex.y * scale) + o.vertex.w) * 0.5;
				o.uvGrab.zw = o.vertex.zw;

				return o;
			}

			half4 frag( v2f i ) : SV_Target
			{
				//noise effect
				half4 offsetColor1 = tex2D(_NoiseTex, i.uvMask + _Time.xz * _HeatTime);
				half4 offsetColor2 = tex2D(_NoiseTex, i.uvMask - _Time.yx * _HeatTime);

				half distortX = ((offsetColor1.r + offsetColor2.r) - 1) * _HeatForce;
				half distorty = ((offsetColor1.g + offsetColor2.g) - 1) * _HeatForce;

				half2 screenUV = (i.vertex.xy / _ScreenParams.xy)+ float2(distortX, distorty);

				half4 grab = tex2D(_CameraTransparentTexture, screenUV);
				half4 mask = tex2D(_MaskTex, i.uvMask);
				half maskA = min(mask.r, mask.a);
				return _TintColor * i.color * half4(grab.rgb, maskA);
			}
			ENDHLSL
		}
	}

	SubShader
	{
		Blend DstColor One
		Pass
		{
			Name "BASE"
			SetTexture[_MaskTex]
			{ 
				constantColor (0,0,0,0)
				combine texture * constant
			}
		}
	}
}