Glossary - Shader

A shader is a computer program that frequently used for shading images, makes them more visible, colorful, and engaging. Generally, the program is used for shading 3D scenes in video games, movies, and short clips. A variety of editing actions regarding the graphics can be done through shading. The primary purpose of using this program is to make GPU (graphic processing unit) of the device understand what action you want to perform. So, a shader is coded directly for Graphics Processing Unit and tells the system how to render each pixel separately. The term is called shader because of the usage factor, though there are several ways for which users can utilize the ability of this program.

Which actions can be performed through this program?

Shader allows users to change colors, the contrast of an image, brightness, hue, saturation, and position. These apply to both textures, vertices, and pixels that form those images. Then, the final result can be obtained through a special algorithm of the program, which will give the user a rendered image in a form that he/she wanted to make. 


The first time the term was used in May of 1988 at Render Man Interface Specification by Pixar. After that, the popularity of the term started to grow, and significant video game developing companies and individuals began to use it. Nowadays, both Direct3D and OpenGL support this matter. Video cards used shaders for the first time in 2001, and that programmable pixel shader was the NV20 GeForce 3.

Graphic Pipeline of the Term

The graphic pipeline of the shader starts with the CPU. The CPU sends instructions and related geometry data to the GPU, which is located on the graphics card. Then, the pixels calculated and divided into triangles. After that, those triangles are subdivided to fragment quads. (1FQ = 2x2 Fragment primitive). In the end, the process continues this way, and those fragments that passed through it are written on the screen.