unity中实现流光效果——世界空间下

Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _FlowColor ("Flow Color", Color) = (1, 1, 1, 1) // 流光颜色
        _FlowFrequency ("Flow Frequency", Float) = 1.0 // 流光频率
        _FlowSpeed ("Flow Speed", Float) = 1.0 // 流光速度
        _FlowAmplitude ("Flow Amplitude", Float) = 0.5 // 流光振幅
        _FlowWidth ("Flow Width", Float) = 0.1 // 流光宽度
        _FlowRotationAngle ("Flow Rotation Angle", Float) = 90.0 // 流光旋转角度，以度为单位
        _FlowPhase ("Flow Phase", Float) = 0.0 // 流光相位
    }
    SubShader
    {
        Tags {
            "RenderType" = "Opaque"
            "Queue" = "Geometry+10"
        }
        LOD 100
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

            #pragma shader_feature _ ENABLE_FLOWLIGHT

            struct appdata
            {
                float4 vertex : POSITION;
                float2 texcoord : TEXCOORD0;
                float3 normal : NORMAL;
            };

            struct v2f
            {
                float4 pos : SV_POSITION;
                float2 uv : TEXCOORD0;
                float3 pos_world : TEXCOORD1;
                float3 pivot_world : TEXCOORD2;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

            float4 _FlowColor;
            float _FlowFrequency;
            float _FlowSpeed;
            float _FlowAmplitude;
            float _FlowWidth;
            float _FlowRotationAngle;
            float _FlowPhase;

            v2f vert (appdata v)
            {
                v2f o;
                o.pos = UnityObjectToClipPos(v.vertex);
                float3 pos_world = mul(unity_ObjectToWorld, v.vertex).xyz;

                o.pos_world = pos_world;
                o.pivot_world = mul(unity_ObjectToWorld, float4(0.0, 0.0, 0.0, 1.0)).xyz;
                o.uv = v.texcoord;
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                half3 baseColor = tex2D(_MainTex, i.uv).rgb;

                #ifdef ENABLE_FLOWLIGHT
                    // 计算相对位置
                    half2 uv_flow = (i.pos_world.xy - i.pivot_world.xy);

                    // 将度数转换为弧度
                    float rad = radians(_FlowRotationAngle);

                    // 计算旋转矩阵
                    float cosTheta = cos(rad);
                    float sinTheta = sin(rad);
                    float2x2 rotationMatrix = float2x2(cosTheta, -sinTheta, sinTheta, cosTheta);

                    // 应用旋转矩阵到UV坐标
                    uv_flow = mul(rotationMatrix, uv_flow);

                    // 计算时间因子，包括相位调整
                    
                    float timeFactor = _Time.y * _FlowSpeed +_FlowPhase;
               
                    // 计算流光效果
                    float wave = sin(_FlowFrequency * uv_flow.x + timeFactor) * _FlowAmplitude;

                    // 构建流光Mask
                    float flowMask = smoothstep(0.5 - _FlowWidth, 0.5, 0.5 + wave) - smoothstep(0.5, 0.5 + _FlowWidth, 0.5 + wave);

                    // 叠加流光颜色
                    float3 final_col = baseColor + flowMask * _FlowColor.rgb;
                #else
                    float3 final_col = baseColor;
                #endif

                return float4(final_col, 1.0);
            }
            ENDCG
        }
    }

UV这样算，可以保证3D模型，流光可以沿着一个方向流动