Water Shader {

Here's a quick demo of a mobile water shader I wrote for an Ipad game (I'll post it when it is released). I used Unity3D with ShaderLab and CG for the shader writing and C# for the scripts. I will try to package it and upload it to the Unity Asset Store soon so others can use it.


Features:

• Efficient shader optimized for mobile devices
• Realtime refraction of anything on opposite side of water plane
• Sin blend between 2 normal maps for smooth normal animation
• UV Panning normal maps
• Reflection Cubemap
• Renders in Opaque queue with no expensive transparency cost
• Separate settings for fog over and under water
• Separate settings for far clip planes over and under water (quality)
• Controls for Transparency, RefractionFactor, ReflectionFactor, RenderTextureSize, Tiling, FogSettings, etc

Here's some more screenshots and a video: (Sorry for bad quality)

And here's the relevent vertex and surface shaders (in CG):

void vert (inout appdata_full v, out Input o) 
{
 fixed4 epos = mul(UNITY_MATRIX_MV, v.vertex );
 
 o.eyeZ = -epos.z;
 
 o.ref = mul( _TextureMatrix, epos );
 
 o.viewDir = ObjSpaceViewDir( v.vertex );
}


void surf (Input IN, inout SurfaceOutput o) 
{
 //Normal map with uv pan based on time:
 fixed4 speed = _Speed * _Time;
 fixed2 UV_Pan0 = IN.uv_Normal + speed.xy;
 fixed2 UV_Pan1 = IN.uv_Normal + speed.yx;
 fixed4 normA =
fixed4(UnpackNormal( tex2D(_Normal,UV_Pan0.xy)).xyz, 1.0 );
fixed4 normB = fixed4(UnpackNormal( tex2D(_Normal2,UV_Pan1.xy)).xyz, 1.0);
 
 fixed4 norm =
lerp( normA, normB, (sin( _Time.x * _SinNormalSpeed ) * 0.8 + 1) * 0.5 );
 
 norm = normalize( norm );
 
 //Refract uvs of refractionTexture in xy
 fixed4 uv2 = IN.ref;
 fixed2 refractUVs =_RefractionFactor * norm.xy;
 uv2.xy += refractUVs;
 
 //calculate fresnel factor for hiding refraction at sheer angle:
 fixed fresnel = saturate( dot( normalize( IN.viewDir ), norm.xzy ));
 fresnel = 1.0 - pow( fresnel, _FresnelFactor ) + 0.5;
 
 //lookup projected refractionTexture:
 half4 refr =
_Color * tex2Dproj( _RefractionTexture, UNITY_PROJ_COORD(uv2) );
 
//lookup reflected cubemap texture:
 half4 refl =
_ReflectionFactor * texCUBE( _ReflectionCube, WorldReflectionVector( IN, norm));
 
//linear fog falloff
 half fogAmount = (IN.eyeZ - _FogStart) / _FogEnd;

 //lerp between reflection and refraction, using fresnel:
 half4 color = lerp( refl, refr, saturate( _Transparency * fresnel) );
 
//lerp btwn color and fog based on fogamount
 color =
lerp( color, saturate(_SurfaceFogColor + norm.x), saturate(fogAmount) );
 
//unlit so assign to emission
 o.Emission = color;
 o.Albedo = 0.0;
 o.Gloss = 0.0;
 o.Alpha = 0.0;
 o.Specular = 0.0;
}

-K