Programming methods to image synthesis is associated with the term “Shader”.
Programming languages are developed exclusively for describing the operation of a shader, as CG (C for Graphics), nVidia, OGLSL (OpenGL Shading Language), OpenGL, and DX HLSL, de Microsoft, Included in DirectX.
In the field of computer graphics, to shader is a computer program that is used to do shading – the production of appropriate levels of light and color within an image – or, in the modern era, also to produce special effects or do postprocessing. A definition in layman‘s terms might be given as “a program that teaches a computer how to draw something in a specific and unique way”.(W)
Each shader allows for an effect type and / or finishing of the image. If one or more apply to an object we say that we are assigning a “material” the same. Objects with the materials that make up the scene, with adequate lighting will get the final image.