Highlighting UI Fields in Unity

It sounds like you’re on the right track with your Unity project! For changing the opacity of specific fields in your UI without affecting the whole image, you have a few options.

1. Using Canvas Groups

A simple way to manage opacity is to use a CanvasGroup. You can create a CanvasGroup component for each of the fields you want to highlight. The alpha value of the CanvasGroup can be tweaked based on user interaction or conditions:

    // Example of changing alpha on interaction:
    CanvasGroup canvasGroup = GetComponent<CanvasGroup>();
    canvasGroup.alpha = 0.5f; // Change to desired opacity
    

2. Custom Shaders

If you’re feeling adventurous and want to go down the shader route, you can create a simple shader that only modifies the opacity of certain areas of your UI. You don’t have to go for something too complex!

    Shader "Custom/OpacityShader" {
        Properties {
            _MainTex ("Texture", 2D) = "white" {}
            _Opacity ("Opacity", Range(0, 1)) = 1
        }
        SubShader {
            Tags { "RenderType"="Opaque" }
            LOD 100
            Pass {
                CGPROGRAM
                #pragma vertex vert
                #pragma fragment frag
                #include "UnityCG.cginc"
                
                struct appdata_t {
                    float4 vertex : POSITION;
                    float2 uv : TEXCOORD0;
                };
                
                struct v2f {
                    float2 uv : TEXCOORD0;
                    float4 vertex : SV_POSITION;
                };
                
                sampler2D _MainTex;
                float _Opacity;

                v2f vert (appdata_t v) {
                    v2f o;
                    o.vertex = UnityObjectToClipPos(v.vertex);
                    o.uv = v.uv;
                    return o;
                }

                fixed4 frag (v2f i) : SV_Target {
                    fixed4 col = tex2D(_MainTex, i.uv);
                    col.a *= _Opacity; // Multiply by opacity
                    return col;
                }
                ENDCG
            }
        }
    }
    

In your UI, you can set the _Opacity value dynamically when the user interacts with specific fields.

3. Using Animator Components

An alternative might be to use Unity’s Animator. You can create animations that change the opacity of your UI elements. This might be an easier path if you aren’t comfortable with coding and shaders!

Final Thoughts

Choose the method that fits best with your skill level and the complexity of your project. If you’re just starting with shaders, the CanvasGroup method might be the best and simplest option to get you going without getting too deep into shader programming. Good luck, and have fun making your UI shine!