Re-Coding a Basic Blinn-Phong Shader with Unity/CG

The art of shaders has always been known for being fairly complex. While a few math operations can easily simulate a flat 3D surface with some lighting and shadows, creating great and optimized visuals for your games can be a hard task. As a beginner, you can always copy-paste some script in the hope that it magically transforms your visuals, but to truly design your own style, you will need quite a lot of time to learn all the ins and outs. Still – shaders are definitely worth digging into, and nowadays, with engines such as Unity, we have an opportunity to discover more about this unique field step by step.

Shaders are how our computers are able to render 3D to 2D, and they are paramount to most modern video games: be it to actually show your 3D scene or to create catchy VFX to bring your world some life, they are a key element to creating visuals. Thanks to their parallel structure, they can also take advantage of our latest GPU-based architectures, and they are blazingly fast. All of this can take some getting used to, for sure; still, the results are pretty amazing once you manage to set everything up properly.

Need some refreshers on the fundamentals of shaders?

If you want to review some essentials on the structure of shaders, the vertex and fragment shader functions, and specific Unity semantics to feel more comfortable when tackling more advanced shading techniques in the upcoming chapters, you can have a look at the Appendix: Some Quick Refreshers on Shaders in Unity, at the end of the book!

So, before we dive into Unity’s newest shading tools and discover the more modern render pipelines, let’s get back into the swing of things with a practical example of how to design and implement a classical shading model: Blinn-Phong.

Although this model is somewhat old and has now mostly been replaced by physically-based rendering, it will be easier to wrap our heads around and discuss in this review chapter. It will also be a good opportunity to do some quick reminders about 3D lighting and about how to perform basic operations such as diffuse, ambient, and specular lighting.

So, in this chapter, we will review the basics of shader coding in Unity with the usual built-in pipeline in a hands-on example. It will take us through all the steps required to create a vertex-fragment shader, debug it, and implement a simple 3D lighting model. We will also learn a few tips for improving the user-friendliness of our material inspectors and better controlling how shader properties are exposed.

We will cover the following topics in this chapter:

• Doing a quick study of the Blinn-Phong shading model
• Setting up our shader in Unity
• Adding the ambient and specular components
• Making a top-notch inspector!