Q. What are Shaders?

A. Shaders add a new dimension to graphics rendering. They allow the transform, lighting, and rendering functionality to be modified at runtime on a vertex, pixel, and screen basis. A shader is a small script that runs on the graphics hardware for every vertex or pixel that is rendered on the screen. This gives the user a new level of flexibility over the way that pixels are rendered. Vertex and pixel shaders can be used for thousands of effects, such as creating water ripples, render cartoon style, cover models with fur, or control the lava flow of a volcano.

Shaders are supported by most newer game engines. Shader support usually includes a collection of standard shaders, as well as an editor that allows users to program their own shaders. Some engines - such as A7 - also support postprocessing shaders and render targets that allow cool effects like realtime reflection and refraction, high dynamic range rendering, deferred shading, or depth-of-field effects as in the underwater image below (screenshots from the Gamestudio user forum).

For editing shaders there are two methods. Visual shader editors allow you to put together shaders from predefined functions. Language-based shader editors allow you to write shaders in a high-level language with C syntax. A shader language offers much greater flexibility, but has the disadvantage that you normally need to write many versions of the same shader for different light and rendering modes. Some engines, such as A7, offer the best of both worlds by using a language together with predefined shader functions that automatically support all possible light and render combinations. If you want to learn the shader language, download the Shader Workshops that introduce into shader programming.