Shader study: Ocean waves using Scrolling textures

Test Scene using Standard Unity Environment Assets:

sea.gif

By moving textures across the surface of an object, interesting fluid effects like moving waterfalls and lava can be created.

This is one by updating UV values so they scroll across the surface of the mesh.

When adding multiple textures together, it’s important to average their colours in order to tone down the combination, otherwise the effect would be too bright.

The UV offset of the two textures are calculated differently so they scroll at a different rate.

Shader “Custom/UVScrollWaterWaves” {
Properties {
_MainTex (“Water”, 2D) = “white” {}
_FoamTex (“Foam”, 2D) = “white” {}
_ScrollX (“Scroll X”, Range(-5,5)) = 1
_ScrollY (“Scroll Y”, Range(-5,5)) = 1
_Freq(“Frequency”, Range(0,5)) = 3
_Speed(“Speed”,Range(0,100)) = 10
_Amp(“Amplitude”,Range(0,1)) = 0.5
}
SubShader {

CGPROGRAM
#pragma surface surf Lambert vertex:vert

sampler2D _MainTex;
sampler2D _FoamTex;
float _ScrollX;
float _ScrollY;
float _Freq;
float _Speed;
float _Amp;

struct Input {
float2 uv_MainTex;
float3 vertColor;
};

struct appdata {
float4 vertex: POSITION;
float3 normal: NORMAL;
float4 texcoord: TEXCOORD0;
float4 texcoord1: TEXCOORD1;
float4 texcoord2: TEXCOORD2;
};

void vert (inout appdata v, out Input o) {
UNITY_INITIALIZE_OUTPUT(Input,o);
float t = _Time * _Speed;
float waveHeight = sin(t + v.vertex.x * _Freq) * _Amp;
v.vertex.y = v.vertex.y + waveHeight;
v.normal = normalize(float3(v.normal.x + waveHeight, v.normal.y, v.normal.z));
o.vertColor = 1;
}

void surf (Input IN, inout SurfaceOutput o) {
_ScrollX *= _Time.x * _Speed;
_ScrollY *= _Time.y * _Speed;
float3 water = (tex2D (_MainTex, IN.uv_MainTex + float2(_ScrollX, _ScrollY))).rgb;
float3 foam = (tex2D (_FoamTex, IN.uv_MainTex + float2(_ScrollX/2.0, _ScrollY/2.0))).rgb;
o.Albedo = (water + foam)/2.0;
}
ENDCG
}
FallBack “Diffuse”
}

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