Time for action – HLSL for lighting

To implement HLSL lighting, perform the following steps:

1. 1. In the declarations area of the Terrain.fx effect file, after textureSampler is declared, add the following variable declarations:

   float3 lightDirection;
   float4 lightColor;
   float lightBrightness;

2. 2. In the VertexShaderInput struct definition, add a new struct component to pass in the normal associated with the vertex as follows:

   float3 Normal : NORMAL0;

3. 3. In the VertexShaderOutput struct definition, add a new struct component to hold the calculated lighting value for the vertex as follows:

   float4 LightingColor : COLOR0;

4. 4. In the VertexShaderFunction() function, add the following lines of code before the line that reads return output;:

   float4 normal = normalize(mul(input.Normal, World));
   float lightLevel = dot(normal, lightDirection);
   output.LightingColor = saturate(
       lightColor * lightBrightness * lightLevel);

5. 5. Replace the current PixelShaderFunction() method with the following:

   float4 PixelShaderFunction...