float4x4 World;
float4x4 View;
float4x4 Projection;
float4 lightDirection = { 1, -0.7, 1, 0};
float textureScale;

texture gTex0;
sampler ColorMapSampler = sampler_state
{
   Texture = <gTex0>;
   MinFilter = ANISOTROPIC;
   MagFilter = ANISOTROPIC;
   MipFilter = Linear;   
   AddressU  = Wrap;
   AddressV  = Wrap;
};

// TODO: add effect parameters here.

struct VertexShaderInput
{
    float4 Position : POSITION0;
    float3 Normal : NORMAL0;

    // TODO: add input channels such as texture
    // coordinates and vertex colors here.
};

struct VertexShaderOutput
{
    float4 Position : POSITION0;
    float3 Normal : TEXCOORD0;
    float3 worldPosition : TEXCOORD1;

    // TODO: add vertex shader outputs such as colors and texture
    // coordinates here. These values will automatically be interpolated
    // over the triangle, and provided as input to your pixel shader.
};

VertexShaderOutput VertexShaderFunction(VertexShaderInput input)
{
    VertexShaderOutput output;

    float4 worldPosition = mul(input.Position, World);
    float4 viewPosition = mul(worldPosition, View);
    output.Position = mul(viewPosition, Projection);

   output.worldPosition = input.Position.xyz / input.Position.w;
   output.Normal = normalize(input.Normal);

    // TODO: add your vertex shader code here.

    return output;
}

float4 PixelShaderFunction(VertexShaderOutput input) : COLOR0
{
   float3 absNormal = abs(input.Normal);
   float3 blend_weights = absNormal;
   blend_weights = blend_weights - 0.2679f;
   blend_weights = max(blend_weights, 0);
   // force sum to 1.0
   blend_weights /= (blend_weights.x + blend_weights.y + blend_weights.z).xxx;

   float4 blended_color;
   float tex_scale = 0.1f;

   float2 coord1 = input.worldPosition.yz * tex_scale;
   float2 coord2 = input.worldPosition.zx * tex_scale;
   float2 coord3 = input.worldPosition.xy * tex_scale;

   float4 col1 = tex2D(ColorMapSampler, coord1);// * 0.01 + float4(1.0,0.0,0.0,1.0); // uncomment to see the blending in red/green/blue only
   float4 col2 = tex2D(ColorMapSampler, coord2);// * 0.01 + float4(0.0,1.0,0.0,1.0);
   float4 col3 = tex2D(ColorMapSampler, coord3);// * 0.01 + float4(0.0,0.0,1.0,1.0);

   blended_color = col1.xyzw * blend_weights.xxxx + 
               col2.xyzw * blend_weights.yyyy + 
               col3.xyzw * blend_weights.zzzz;

   // directional lighting
   //float4 light = -normalize(lightDirection);
   //float ldn = max(0, dot(light, input.Normal));
   //float ambient = 0.2f;

   //return float4(blended_color.xyz * (ambient + ldn), 1);
   return float4(blended_color.xyz, 1);
}

technique Technique1
{
    pass Pass1
    {
        // TODO: set renderstates here.
      CULLMODE = CCW;
      ZENABLE = TRUE;
        ZWRITEENABLE = TRUE;
        VertexShader = compile vs_1_1 VertexShaderFunction();
        PixelShader = compile ps_2_0 PixelShaderFunction();
    }
}