A simpler version of the UI Shader for mobile and low spec devices

UI-Fast-Default

Shader "UI/Fast-Default"
{
	Properties
	{
		[PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
		_Color ("Tint", Color) = (1,1,1,1)
	}

	SubShader
	{
		Tags
		{ 
			"Queue"="Transparent" 
			"IgnoreProjector"="True" 
			"RenderType"="Transparent" 
			"PreviewType"="Plane"
			"CanUseSpriteAtlas"="True"
		}

		Cull Off
		Lighting Off
		ZWrite Off
		ZTest [unity_GUIZTestMode]
		Blend SrcAlpha OneMinusSrcAlpha

		Pass
		{
		CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag

			#include "UnityCG.cginc"
			#include "UnityUI.cginc"
			
			struct appdata_t
			{
				float4 vertex   : POSITION;
				float4 color    : COLOR;
				float2 texcoord : TEXCOORD0;
			};

			struct v2f
			{
				float4 vertex   : SV_POSITION;
				fixed4 color    : COLOR;
				half2 texcoord  : TEXCOORD0;
				float4 worldPosition : TEXCOORD1;
			};
			
			fixed4 _Color;
			fixed4 _TextureSampleAdd;
			v2f vert(appdata_t IN)
			{
				v2f OUT;
				OUT.worldPosition = IN.vertex;
				OUT.vertex = mul(UNITY_MATRIX_MVP, OUT.worldPosition);

				OUT.texcoord = IN.texcoord;
				
				#ifdef UNITY_HALF_TEXEL_OFFSET
				OUT.vertex.xy += (_ScreenParams.zw-1.0)*float2(-1,1);
				#endif
				
				OUT.color = IN.color * _Color;
				return OUT;
			}

			sampler2D _MainTex;
			fixed4 frag(v2f IN) : SV_Target
			{
				return (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color;
			}
		ENDCG
		}
	}
}