water_vertex.cg

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float fast_fresnel(float3 I, float3 N, float3 fresnelValues)
{
    float power = fresnelValues.x;
    float scale = fresnelValues.y;
    float bias = fresnelValues.z;

    return bias + pow(1.0 + dot(I, N), power) * scale;
}

float3 myrefract(float3 i, float3 n, float eta)
{
    float cosi = dot(-i, n);
    float cost2 = 1.0 - eta * eta * (1.0 - cosi*cosi);
    float3 t = eta*i + ((eta*cosi - sqrt(abs(cost2))) * n);
    return t * float3(cost2 > 0.0);
}

void main(float4 position : POSITION,
		  float3 normal   : NORMAL,

		  out float4 oPosition  : POSITION,
		  out float3 incident   : TEXCOORD0,
		  out float3 n_out      : TEXCOORD1,
		  //out float3 incident   : TEXCOORD2,
		  out float reflectionFactor : COLOR,

		  //uniform float3 eyePositionW,
		  uniform float3 fresnelValues,
		  uniform float4x4 texMatrix,
		  uniform float4x4 modelViewProj, 
		  uniform float4x4 modelToWorld)
{
	float3 eyePositionW = float3(0.0, 0.0, 0.0);

	oPosition = mul(modelViewProj, position);

	float3 posW = mul(modelToWorld, position).xyz;
	//posW *= 0.1;
//	positionW = mul(texMatrix, float4(positionW, 1.0f)).xyz;
	float3 N = mul((float3x3)modelToWorld, normal);

	//transpose(modelToWorld);
//	n_out = mul((float3x3)texMatrix, mul(modelToWorldIT, normal).xyz);
//	n_out = mul((float3x3)texMatrix, mul((float3x3)modelToWorld, normal).xyz);
	n_out = mul((float3x3)texMatrix, N);//mul((float3x3)modelToWorld, normal).xyz);
	N = normalize(N);
	//n_out = mul(modelViewProj, normal);

	/** incident vector **/
	incident = posW - eyePositionW;
	float3 I = normalize(incident);//posW - eyePositionW);
//	float3 I = (posW - eyePositionW);


	float etaRatio = 1.3; // water
	//float etaRatio = 1.1; // glass
	//T = mul((float3x3)texMatrix, I.xyz).xyz;
	
	//R = mul((float3x3)texMatrix, reflect(I, N).xyz).xyz;
	incident = mul((float3x3)texMatrix, incident);//refract(I, N, etaRatio).xyz).xyz;


	//T = refract(I, N, etaRatio);
	//R = reflect(I, N);
	//
	reflectionFactor = fast_fresnel(I, N, fresnelValues);
}