2D Flag Wave Shader

FlagShader.shader

Shader "Custom/UIManualWaveControl"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _WaveProgress ("Wave Progress (0-1)", Float) = 0.0
        _WaveAmplitude ("Wave Amplitude", Float) = 5.0
        _WaveFrequency ("Wave Frequency", Float) = 2.0
        _BendAmount ("Bend Amount", Float) = 0.2
    }
    SubShader
    {
        Tags { "RenderType"="Transparent" "Queue"="Overlay" }
        LOD 100

        Pass
        {
            Cull Off ZWrite Off Blend SrcAlpha OneMinusSrcAlpha

            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 _WaveProgress;     // Custom wave control parameter (range: 0-1)
            float _WaveAmplitude;    // Amplitude of the wave
            float _WaveFrequency;    // Frequency of the wave
            float _BendAmount;       // Amount of horizontal bend

            v2f vert (appdata_t v)
            {
                v2f o;

                // Get original vertex position
                float3 pos = v.vertex;

                // Calculate the wave effect using the custom _WaveProgress parameter
                float wave = sin(pos.x * _WaveFrequency + _WaveProgress * 3.14159) * _WaveAmplitude;

                // Calculate the horizontal bend using a sine curve for smooth S-shaped flag waving
                float curve = _BendAmount * sin(pos.y * 3.14159); // Create smooth horizontal curve using sine

                // Modify X position to create smooth curvature along the Y-axis
                pos.x += curve * pos.y;

                // Apply the waving effect on Y-axis based on custom progress
                pos.y += wave;

                // Convert to Clip Space
                o.vertex = UnityObjectToClipPos(float4(pos, 1.0));

                // Pass UV coordinates to fragment shader
                o.uv = v.uv;
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                // Sample the main texture
                return tex2D(_MainTex, i.uv);
            }
            ENDCG
        }
    }
}