evershade/Assets/Shaders/GradientShaderWithAngle.shader

Shader "Custom/GradientShaderWithAngle"
{
    Properties
    {
        _Color1 ("Start Color", Color) = (1,0,0,1)
        _Color2 ("End Color", Color) = (0,0,1,1)
        _Angle ("Angle", Range(0, 360)) = 0
    }
    SubShader
    {
        Tags
        {
            "RenderType"="Transparent" "Queue"="Overlay"
        }
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

            struct appdata_t
            {
                float4 vertex : POSITION;
                float2 texcoord : TEXCOORD0;
            };

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

            float4 _Color1;
            float4 _Color2;
            float _Angle;

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

            fixed4 frag(v2f i) : SV_Target
            {
                // Convert angle to radians
                float angleRad = radians(_Angle);
                // Compute rotated UVs
                float2 rotatedUV = float2(
                    cos(angleRad) * i.texcoord.x - sin(angleRad) * i.texcoord.y,
                    sin(angleRad) * i.texcoord.x + cos(angleRad) * i.texcoord.y
                );
                // Compute gradient
                float gradient = rotatedUV.y; // Adjust to .x for horizontal, .y for vertical
                fixed4 color = lerp(_Color1, _Color2, gradient);
                return color;
            }
            ENDCG
        }
    }
    FallBack "Diffuse"
}