float4x4 view_proj_matrix;
float4 Light_Ambient;
float4 Light1_Position;
float4 Light1_Attenuation;
float4 Light1_Color;
float4 view_position;
float4x4 inv_view_matrix;
float4x4 view_matrix;
float4 rflxColor;

struct VS_OUTPUT
{
   float4 Pos:      POSITION;
   float2 TexCoord: TEXCOORD0;
   float4 Color:    COLOR0;
};

float4 Light_Point(
    float3 VertPos,
    float3 VertNorm,
    float3 LightPos,
    float4 LightColor,
    float3 EyeDir)
    

{   // This stuff happens per vertex, so, we want a LightColor as result

    // Determine the distance from the light to the vertex and the direction
    float3 LightDir = LightPos - (VertPos);
    float  Dist = length(LightDir);
    float3 LightV = LightDir / Dist;
    
    // Compute half vector
    float3 HalfVect = normalize(LightV-EyeDir);
    
    // Specular
    float SpecularAttn = pow( clamp(0,1, dot(VertNorm, HalfVect)),128);
//==============================================================================//    
    // Special Reflectivity
    float4 rflxBRDF = pow(max(0, dot(LightV,HalfVect+0.03)), dot(32,LightV) );
    // here we can clamp the effect, so we see color
    rflxBRDF = clamp(rflxBRDF,0,5.5);
    // filter the inner material color
    rflxBRDF *= rflxColor;
//==============================================================================//
    // Diffuse
    float AngleAttn = clamp(0,1, dot(VertNorm, LightV) );
        
    // Compute final lighting
    return LightColor * (SpecularAttn+AngleAttn+(rflxBRDF));
}

VS_OUTPUT vs_main(
    float4 inPos:    POSITION,
    float3 inNormal: NORMAL,
    float2 inTxr:    TEXCOORD0)
{
   VS_OUTPUT Out;

    // Compute the position and send out the texture coordinates
    Out.Pos = mul(view_proj_matrix, inPos);
    Out.TexCoord = inTxr;

    // Determine the eye vector
    float3 EyeVector = -normalize(mul(inv_view_matrix,vector(0,0,10,1))+inPos);
    
    // Compute light contribution
    float4 Color = Light_Point(inPos, // vert position  (P)
                         inNormal,             // vert normal    (N)
                         Light1_Position,      // light position (lP1)
                         Light1_Color,         // light color    (lC1)
                         EyeVector);           // eye vector     (I)
    // clamp the color to prevent lightwrapping, add ambient
    Color = clamp(Color,0,1) + Light_Ambient;

    // Output Final Color
    Out.Color = Color;

   return Out;
}