Reading the G-Buffer

In this recipe, we will look at the HLSL shader code necessary to read from the G-Buffer's resources. We will then use the screen-aligned quad to implement a debug pixel shader for displaying information from the G-Buffer to screen.

Getting ready

We will follow on from where we left off with Filling the G-Buffer using the same G-Buffer layout as described in that recipe, and make use of the screen-aligned quad from Implementing a screen-aligned quad renderer.

How to do it…

First let's begin by outlining the HLSL code necessary to extract the attributes from the G-Buffer.

1. We'll start by defining a structure to store the loaded G-Buffer attributes in, as shown in the following HLSL code snippet:

   // Structure for holding loaded G-Buffer attributes
   struct GBufferAttributes
   {
       float3 Position;
       float3 Normal;
       float3 Diffuse;
       float SpecularInt; // specular intensity
       float3 Emissive;
       float SpecularPower;
   };
   // Screen-aligned Quad PixelIn
   struct PixelIn
   {
     ...