// Global variables 
//----------------------------------------------------------------------------- 
float4x4 mWorldViewProj;  // World * View * Projection transformation 
float4x4 mInvWorld;       // Inverted world matrix 
float3 mLightPos;         // Light position 

struct VS_OUTPUT 
{ 
   float4 Position: POSITION0; 
   float2 TexCoord:   TEXCOORD0; 
   float2 diffuse: TEXCOORD1; 
}; 


VS_OUTPUT vertexMain( 
   float4 Position: POSITION0, 
   float2 TexCoord: TEXCOORD0, 
   float2 diffuse: TEXCOORD1, 
   float3 Normal:   NORMAL0) 
{ 
   VS_OUTPUT Output; 

   // calculate light vector 
   float3 N = normalize(Normal); 
   float3 L = normalize(mLightPos - Position.xyz); 

   // Calculate diffuse component 
   diffuse.x = max(dot(N, L),0); 

   // Shading offset 
   float offset = 0.0001f; 
    
   //Subtract the offset and clamp the texture to 0 
   diffuse = float2(clamp(diffuse.x+offset,0,1),0.5); 

   Output.Position = mul(Position,mWorldViewProj); 
   Output.diffuse = diffuse; 
   Output.TexCoord = TexCoord; 
   return( Output ); 
} 
    
sampler2D tex0 : register(s0) ; 
sampler2D diffuseRamp : register(s1) ; 

float4 pixelMain( 
   float2 TexCoord:     TEXCOORD0, 
      float2 diffuseIn:    TEXCOORD1 
   ) : COLOR0 
{ 
   float4 color = float4(1,1,1,1); 
   float4 diffuse =  float4(0.8f, 0.8f, 0.8f, 1.0f)*tex2D(tex0, TexCoord); 
   // Step functions from textures 
   float4 diffuseInc = tex2D(diffuseRamp, diffuseIn); 

      
    
   color = (diffuse * diffuseInc); 
     
   
      return( color); 
  
}