iPhone 3D Programming

Chapter 4. Adding Depth and Realism

Lumos!

—Harry Potter and the Chamber of Secrets, J.K. Rowling

When my wife and I go out to see a film packed with special effects, I always insist on sitting through the entire end credits, much to her annoyance. It never ceases to amaze me how many artists work together to produce a Hollywood blockbuster. I’m often impressed with the number of artists whose full-time job concerns lighting. In Pixar’s Up, at least five people have the title “lighting technical director,” four people have the title “key lighting artist,” and another four people have the honor of “master lighting artist.”

Lighting is obviously a key aspect to understanding realism in computer graphics, and that’s much of what this chapter is all about. We’ll refurbish the wireframe viewer sample to use lighting and triangles, rechristening it to Model Viewer. We’ll also throw some light on the subject of shaders, which we’ve been glossing over until now (in ES 2.0, shaders are critical to lighting). Finally, we’ll further enhance the viewer app by giving it the ability to load model files so that we’re not stuck with parametric surfaces forever. Mathematical shapes are great for geeking out, but they’re pretty lame for impressing your 10-year-old!

Examining the Depth Buffer

Before diving into lighting, let’s take a closer look at depth buffers, since we’ll need to add one to wireframe viewer. You might recall the funky framebuffer object (FBO) setup code in the HelloCone sample presented ...