How do i add this code to my shader script. Please help

Questions & Answers
1

Hi,
so I have this blur shader I use for my UI image, it works perfectly fine in Editor and PC however on android it flips my screen on the y axis, I found out its caused by android not using Direct3D and people fix this issue by adding this line of code as even the Unity documentation suggests:

The line of code:

#if UNITY_UV_STARTS_AT_TOP
if (_MainTex_TexelSize.y < 0)
        uv.y = 1-uv.y;
#endif

However my skills in shader scripts are super limited and i don’t really know how to implement this line of code to the whole script (its asset I’m using, I didn’t made it) this is my shader script

Shader "Krivodeling/UI/UI Blur"
{
Properties
{
    _MainTex("Texture", 2D) = "white" {}
    _Color("Color", Color) = (1, 1, 1, 1)
    [Toggle] _FlipX("Flip X", float) = 0
    [Toggle] _FlipY("Flip Y", float) = 1
    _Intensity("Intensity", Range(0, 1)) = 0
    _Multiplier("Multiplier", Range(0, 1)) = 0.15
}

    SubShader
    {
        Tags { "Queue" = "Transparent" }
        GrabPass { }
        Pass
        {
                CGPROGRAM
                #pragma debug
                #pragma vertex vert
                #pragma fragment frag 

                #ifndef SHADER_API_D3D11
                #pragma target 3.0
                #else
                #pragma target 4.0
                #endif

                sampler2D _GrabTexture : register(s0);
                sampler2D _MainTex;
                half4 _Color;
                float _FlipX;
                float _FlipY;
                float _Intensity;
                float _Multiplier;

                struct data
                {
                    float4 vertex : POSITION;
                    float3 normal : NORMAL;
                };

                struct v2f
                {
                    float4 position : POSITION;
                    float4 screenPos : TEXCOORD0;
                };

                v2f vert(data i)
                {
                    v2f o;
                    o.position = UnityObjectToClipPos(i.vertex);
                    o.screenPos = o.position;

                    return o;
                }

                half4 frag(v2f i) : COLOR
                {
                    float2 screenPos = i.screenPos.xy / i.screenPos.w;
                    float depth = _Intensity * _Multiplier / 200;

                    if (_FlipX)
                        screenPos.x = 1 - (screenPos.x + 1) * 0.5;
                    else
                        screenPos.x = (screenPos.x + 1) * 0.5;

                    if (_FlipY)
                        screenPos.y = (screenPos.y + 1) * 0.5;
                    else
                        screenPos.y = 1 - (screenPos.y + 1) * 0.5;

                    half4 sum = half4(0.0h, 0.0h, 0.0h, 0.0h);

                    sum += tex2D(_GrabTexture, float2(screenPos.x - 5.0 * depth, screenPos.y + 5.0 * depth)) * 0.025;
                    sum += tex2D(_GrabTexture, float2(screenPos.x + 5.0 * depth, screenPos.y - 5.0 * depth)) * 0.025;

                    sum += tex2D(_GrabTexture, float2(screenPos.x - 4.0 * depth, screenPos.y + 4.0 * depth)) * 0.05;
                    sum += tex2D(_GrabTexture, float2(screenPos.x + 4.0 * depth, screenPos.y - 4.0 * depth)) * 0.05;

                    sum += tex2D(_GrabTexture, float2(screenPos.x - 3.0 * depth, screenPos.y + 3.0 * depth)) * 0.09;
                    sum += tex2D(_GrabTexture, float2(screenPos.x + 3.0 * depth, screenPos.y - 3.0 * depth)) * 0.09;

                    sum += tex2D(_GrabTexture, float2(screenPos.x - 2.0 * depth, screenPos.y + 2.0 * depth)) * 0.12;
                    sum += tex2D(_GrabTexture, float2(screenPos.x + 2.0 * depth, screenPos.y - 2.0 * depth)) * 0.12;

                    sum += tex2D(_GrabTexture, float2(screenPos.x - 1.0 * depth, screenPos.y + 1.0 * depth)) * 0.15;
                    sum += tex2D(_GrabTexture, float2(screenPos.x + 1.0 * depth, screenPos.y - 1.0 * depth)) * 0.15;

                    sum += tex2D(_GrabTexture, screenPos - 5.0 * depth) * 0.025;
                    sum += tex2D(_GrabTexture, screenPos - 4.0 * depth) * 0.05;
                    sum += tex2D(_GrabTexture, screenPos - 3.0 * depth) * 0.09;
                    sum += tex2D(_GrabTexture, screenPos - 2.0 * depth) * 0.12;
                    sum += tex2D(_GrabTexture, screenPos - 1.0 * depth) * 0.15;
                    sum += tex2D(_GrabTexture, screenPos) * 0.25;
                    sum += tex2D(_GrabTexture, screenPos + 1.0 * depth) * 0.025;
                    sum += tex2D(_GrabTexture, screenPos + 2.0 * depth) * 0.05;
                    sum += tex2D(_GrabTexture, screenPos + 3.0 * depth) * 0.09;
                    sum += tex2D(_GrabTexture, screenPos + 4.0 * depth) * 0.12;
                    sum += tex2D(_GrabTexture, screenPos + 5.0 * depth) * 0.15;

                    return sum / 2 * _Color;
                }

            ENDCG
            }
    }
        Fallback Off
    }

Really appreciate any form of help, my last two posts regarding this topic were completely ignored so I did more research and got all the way to this savior line of code I don’t really know how to implement.

2

As per the documentation it says to add it to your vertex shader

i.e.

v2f vert(data i)
{
    v2f o;
    o.position = UnityObjectToClipPos(i.vertex);
    o.screenPos = o.position;

    #if UNITY_UV_STARTS_AT_TOP
    if (_MainTex_TexelSize.y < 0)
        o.screenPos.y = 1-o.screenPos.y;
    #endif

    return o;
}