Introduction

Image processing is the process of applying a signal-processing technique against an input image. The input image is generally a two-dimensional signal with the output being either another image or any properties derived from the input signal.

During this chapter, we will implement a number of filtering techniques using compute shaders (also known as DirectCompute). Utilizing compute shaders for this process allows us to provide image processing in general applications, including non-UI applications, and in some cases is able to achieve a significant performance improvement over pixel shaders (most notably large radius filters). In some circumstances it may be desirable to implement the filter technique within a pixel shader by rendering to a screen-aligned quad, although we lose some of the unique capabilities of the compute shader when doing so—such an example might be small radius blurs where we can utilize the bilinear hardware support.

One of the main advantages of compute...