Custom UI Shader - Refresh?

Unity Engine
1

I’ve made a custom UI shader that I use in a material, and it works great. The problem is that unity seems to render this thing once, and not again even though properties of this material change.

Is there a way to instruct unity to refresh a UI element if its material properties have changed?

In my case, I’m changing the cutoff property, but changes are not reflected in play mode.

Shader "Custom/UI Transparent Cutout"
{
    Properties
    {
        [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
        _Color ("Tint", Color) = (1,1,1,1)
     
        _StencilComp ("Stencil Comparison", Float) = 8
        _Stencil ("Stencil ID", Float) = 0
        _StencilOp ("Stencil Operation", Float) = 0
        _StencilWriteMask ("Stencil Write Mask", Float) = 255
        _StencilReadMask ("Stencil Read Mask", Float) = 255

        _ColorMask ("Color Mask", Float) = 15
        _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
    }

    SubShader
    {
        Tags
        {
            "Queue"="Transparent"
            "IgnoreProjector"="True"
            "RenderType"="Transparent"
            "PreviewType"="Plane"
            "CanUseSpriteAtlas"="True"
        }
     
        Stencil
        {
            Ref [_Stencil]
            Comp [_StencilComp]
            Pass [_StencilOp]
            ReadMask [_StencilReadMask]
            WriteMask [_StencilWriteMask]
        }

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

        Pass
        {
        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.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;
            };
         
            fixed4 _Color;
            sampler2D _MainTex;
            fixed _Cutoff;

            v2f vert(appdata_t IN)
            {
                v2f OUT;
                OUT.vertex = mul(UNITY_MATRIX_MVP, IN.vertex);
                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;
            }

            fixed4 frag(v2f IN) : SV_Target
            {
                half4 color = tex2D(_MainTex, IN.texcoord) * IN.color;
                clip (color.a - _Cutoff);
                color.a = 1;
                return color;
            }
        ENDCG
        }
    }
}

Basically, it’s just the default ui shader but with a cutout (clip).

2

When using the unlit cutout shader instead, it does work and it refreshes automatically. But unity is throwing a bunch of warnings “Material doesn’t have stencil properties”.

But it does work!

3

This post is the first hit on my favourite search engine, but doesn’t cover a proper solution. More discussion is here: Masked UI Element's Shader Not Updating

for me using materialForRendering.SetXYZ made it work.