// oceanHLSL_Cg.frag
// fragment program for Ocean water simulation
// 04 Aug 2005
// adapted for Ogre by nfz
// original shader source from Render Monkey 1.6 Reflections Refractions.rfx
// can be used in both Cg and HLSL compilers

// 06 Aug 2005: moved uvw calculation from fragment program into vertex program

float4 main(float3 uvw: TEXCOORD0, float3 normal: TEXCOORD1, float3 vVec: TEXCOORD2, float4 projectionCoord: TEXCOORD3,
	uniform float fadeBias,
	uniform float fadeExp,
	uniform float4 waterColor,
	uniform sampler Noise,
	uniform sampler skyBox

) : COLOR
{
   float2 final = projectionCoord.xy / projectionCoord.w;
   float3 noisy = tex3D(Noise, uvw).xyz;

   // convert to Signed noise
   float3 bump = 2 * noisy - 1;
   bump.xz *= 0.05;
   //bump = noisy;
   // Make sure the normal always points upwards
   // note that Ogres y axis is vertical (RM Z axis is vertical)
   bump.y = 0.8 * abs(bump.y) + 0.2;
   // Offset the surface normal with the bump
   //bump = normalize(normal + bump);

   // Find the reflection vector
   float3 normView = normalize(vVec);
   //float3 normView = vVec;
   //float3 reflVec = reflect(-normView, -bump);
   // Ogre has z flipped for cubemaps
   //reflVec.z = -reflVec.z;
   //float4 refl = tex2D(skyBox, reflVec);
   final += bump.xz;
   //float4 refl = tex2D(skyBox, reflVec);
   // set up for fresnel calc
   float lrp = 1 - dot(normView, bump);
   float4 refl = tex2D(skyBox, final);
   refl.w = waterColor.w;
   // Interpolate between the water color and reflection for fresnel effect
   float4 col = lerp(waterColor, refl, saturate(fadeBias + pow(lrp, fadeExp)));
   //col.a = 0.5;
   return col;

}