Shader "Text/Gradient" {
    Properties {
        _MainTex ("Font Texture", 2D) = "white" {}
        _Color ("Text Color", Color) = (1,1,1,1)
        _Color1 ("Color 1", Color) = (1,0,0,1)
        _Color2 ("Color 2", Color) = (0,0,1,1)
    }
 
    SubShader {
        Tags { "Queue"="Transparent" }
        Lighting Off Cull Off ZWrite Off Fog { Mode Off }
        Blend SrcAlpha OneMinusSrcAlpha
        Pass {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"
 
            struct appdata_t {
                float4 vertex : POSITION;
                fixed4 color : COLOR;
                float2 texcoord : TEXCOORD0;
            };
 
            struct v2f {
                float4 vertex : SV_POSITION;
                fixed4 color : COLOR;
                float2 texcoord : TEXCOORD0;
            };
 
            sampler2D _MainTex;
            float4 _MainTex_ST;
            fixed4 _Color;
            fixed4 _Color1;
            fixed4 _Color2;
 
            v2f vert (appdata_t v) {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.color = v.color * _Color;
                o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
                return o;
            }
 
            fixed4 frag (v2f i) : SV_Target {
                fixed4 col = tex2D(_MainTex, i.texcoord);
                col *= i.color;
                float lerpFactor = i.texcoord.x; // 可以根据需要调整渐变方向和方式，这里使用x坐标作为示例
                col.rgb = lerp(col.rgb * _Color1.rgb, col.rgb * _Color2.rgb, lerpFactor);
                return col;
            }
            ENDCG
        }
    }
}