Shader in Unity implements UI streamer effect

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Preface

In many game UIs, the effect of a light sweeping across the UI is implemented.

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1. Implementation Idea 1:

1. Collect two textures, one is the main texture and the other is the sweep texture.

2. Define a two-dimensional variable "uv2" in v2f to store the offset value of uv

3. In the vertex shader, imitate the previous uv flow effect, multiply it with _Time and store it in uv2

• Shader time_Time in Unity

4. Finally, the streamer texture uses uv2 sampling and the main texture uses uv sampling results to add and output.

Note:Because this is the Shader of UGUI, remember to change the rendering order to transparent level and blending mode
Tags {"Queue" = "TransParent"}
Blend SrcAlpha OneMinusSrcAlpha

2. Implementation idea 2 (calculate the area):

Code:

Shader "MyShader/UILight"
{
	Properties
	{
		_MainTex ("Texture", 2D) = "white" {}
		
		// 速度 默认左->右
		_Speed ("Speed", range(-2, 2)) = 1.04
		
		// 宽度
		_Width ("Width", range(1, 10)) = 5.83

		// 角度
		_Angle ("Angle", range(-1, 1)) = 0.33

		// 亮度
		_Light ("Light", range(0, 1)) = 0.51
	}
	SubShader
	{
		Tags {"Queue" = "TransParent"}
		LOD 100
		
        //混合模式
        Blend SrcAlpha OneMinusSrcAlpha
			
		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			
			#include "UnityCG.cginc"

			struct appdata
			{
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
			};

			struct v2f
			{
				float2 uv : TEXCOORD0;
				float4 vertex : SV_POSITION;
			};

			sampler2D _MainTex;
			
			v2f vert (appdata v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.uv = v.uv;
				return o;
			}
			
			float _Speed; 
			float _Width; 
			float _Angle; 
			float _Light; 
			fixed4 frag (v2f i) : SV_Target
			{
				fixed4 col = tex2D(_MainTex, i.uv);
				float x = i.uv.x + i.uv.y * _Angle;
				float v = sin(x - _Time.w * _Speed);
				v = smoothstep(1 - _Width / 1000, 1.0, v);
				float3 target = float3(v, v, v) + col.rgb;
				col.rgb = lerp(col.rgb, target, _Light);
				return col;
			}
			ENDCG
		}
	}
}

Effect:

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Reference article

• Unity3D Shader series UI streamer effect
• Unity streamer shader, no picture required