Article: Shaders – Texturing

by Daniel Greenheck

A simple box with a stone black texture

This tutorial will cover attaching an image (I'll be using the word texture from now on) to a model to give it a much more detailed look. Texturing is an essential of creating a realistic scene because it allows us to give objects very fine detail. Without textures, everything in the scene would basically be one color, look very flat and just be generally boring. The right textures can even give an object the illusion of depth, further increasing the realism. The stone box above looks like it has deep cracks in it between the blocks, but that's just an illusion. The entire box is defined using eight vertices. To geometrically represent those cracks, it would take thousands of vertices, something that definitely isn't feasible.

Article: Shaders – Specular Lighting

by Daniel Greenheck

What should I be familiar with before I go through this tutorial?
- The content discussed in the introduction, ambient and diffuse tutorials.

One Thing Before I Begin...

To keep things succinct, I will no longer explain or comment things explained in previous tutorials. Throughout these series of tutorials, I'm going to expect you've gone through the previous tutorials. No sense in beating a dead horse. So if you look at the variables section and only see the Specular variables, rest assured the others are still in the actual program. I just think it will be easier for you as a reader if I only present you with new information. That aside, let's begin!

What is Specular Lighting?

Specular lighting in one word: shiny. The world specular in itself means a mirror-like surface, so you can imagine that anything that has specular lighting is very reflective, causing it to have shiny highlights. If you place a polished chrome ball under a direct light source, you'll probably see a big shiny spot blinding you; this is the specular highlight. Specular reflections are caused by the reflection of the actual light source itself. If the surface isn't flat however, it will warp the light and you'll usually see it as a small dot of bright light or curved lines of light. When you're out on a sunny day, look around at smooth, metallic objects and notice their specular highlights. Try and determine how the light is coming in and being reflected off the surface to your eye. The more you understand about real-world lighting, the better you'll understand what we're trying to replicate in our shaders.

The perfect example of specular lighting. Notice the highlight is really the reflection of the sun.

Article: Shaders – Diffuse Lighting

by Daniel Greenheck

What should I be familiar with before I go through this tutorial?
- The content discussed in the introduction and ambient shader tutorials.
- A simple knowledge of vectors, matrices and dot products (click on the links for Wiki articles) will REALLY help you understand some of the light calculations going on. although I'll do my best to explain those topics in this tutorial.

What is Diffuse Lighting?

Diffuse lighting can best be described as directional light. There are three types of diffuse lighting: directional, point light and spotlight. I have a picture of each below in respective order. Directional light comes down at the same angle no matter where you are standing; the light has no position, just direction. Point light is like a light bulb, it all emanates  from a single point equally in all directions. A spot light is like an oriented floodlight or a flashlight. Diffuse light also creates shadows, but that's a much more advanced topic we won't dive in to until later.