float4x4 matWorldViewProj;
float4x4 matWorld;
float4 vecLightDir;

struct VS_OUTPUT
{
    float4 Pos : POSITION;
    float2 UV : TEXCOORD0;
    float3 Light : TEXCOORD1;
    float3 Norm : TEXCOORD2;
};

VS_OUTPUT VS(float4 Pos : POSITION, float2 UV : TEXCOORD0, float3 Normal : NORMAL)
{
    VS_OUTPUT Out = (VS_OUTPUT)0;
    Out.Pos = mul(Pos, matWorldViewProj); // transform Position
    Out.UV = UV; // pass UV coordinates on
    Out.Light = normalize(vecLightDir); // output light vector
    Out.Norm = normalize(mul(Normal, matWorld)); // transform Normal and normalize it
    return Out;
}

float4 PS(float2 UV : TEXCOORD0, float3 Light : TEXCOORD1, float3 Norm : TEXCOORD2, sampler2D tex0) : COLOR
{
    float4 diffuse = tex2D ( tex0, UV );
    float4 ambient = {0.05, 0.05, 0.075, 1.0};
    return ambient + diffuse * saturate(dot(Light, Norm));
}

technique EntryPoint
{
    pass SinglePass
    {
        VertexShader = compile vs_2_0 VS ( );
	PixelShader = compile ps_2_0 PS ( );
    }
}

void Render ( )
{
	unsigned int num_passes;

	// clear the back- and z-buffer
	device->Clear ( 0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, D3DCOLOR_XRGB ( clear_color.r, clear_color.g, clear_color.b ), 1.0f, 0 );

	effect->Begin ( &num_passes, 0 );

	for ( unsigned int pass = 0; pass < num_passes; pass++ )
	// loop through all passes
	{
		effect->BeginPass ( pass );

		DWORD old_fvf = NULL;
	
		// get current flexible vertex format
		device->GetFVF ( &old_fvf );

		// set format for our models
		device->SetFVF ( D3DFVF_XYZ | D3DFVF_NORMAL | D3DFVF_TEX2 );

		std::vector<Model*>::iterator i;
		for ( i = model.begin ( ); i < model.end ( ); i++ )
		// loop through all models
		{
			// apply the matrix transformations for the model
			(*i)->ApplyMatrixTransformations ( device );
				
			// now get combined matrix (ie. the world-view-projection matrix)
			D3DXMATRIX combined_matrix = GetCombinedMatrix ( );

			effect->SetMatrix ( "matWorldViewProj", &combined_matrix );

			D3DXMATRIX world_matrix;

			// get world matrix
			device->GetTransform ( D3DTS_WORLD, &world_matrix );

			effect->SetMatrix ( "matWorld", &world_matrix );

			D3DXVECTOR4 light_vector ( 0.0f, 0.0f, 1.0f, 0.0f );

			effect->SetVector ( "vecLightDir", &light_vector );

			// make sure all values send to the shader are updated
			effect->CommitChanges ( );

			// render model
			(*i)->Render ( device );
		}

		// reset to old format
		device->SetFVF ( old_fvf );

		effect->EndPass ( );
	}

	effect->End ( );
}

Out.Norm = normalize(mul(Normal, (float3x3)matWorld));