3D GLOSSARY

Scanline Rendering
Rendering technique, or family of algorithms, that renders a scene one row of pixels (or scanline) at a time. It works on a row-by-row basis rather than a polygon-by-polygon or pixel-by-pixel basis.

Shader
A computer program used to determine the final surface properties of an object or image. This often includes arbitrarily complex descriptions of light absorption, diffusion, texture mapping, reflection, refraction, shadowing, surface displacement and post-processing effects. In real-time shading languages there are two different applications of shaders: vertex shaders and pixel shaders.

SSS
Sub-Surface Scattering. The effect of light penetrating a surface and illuminating the inner layers. Very important to consider when simulating realistic skin and most other organic materials.

Texel
Texture element.  A pixel that is part of a texture map.

Texture mapping
The process of assigning (mapping) an image (texture) to a 3d surface. This allows a complicated colouring of the surface without requiring additional polygons to represent minute details.

Tone mapping
It´s a technique used to approximate the appearance of high dynamic range images in media with a more limited dynamic range. Print-outs, CRT or LCD monitors, and projectors all have a very limited dynamic range.
Essentially, tone mapping addresses the problem of strong contrast reduction from the scene values (radiance) to the displayable range while preserving the image details and color appearance important to appreciate the original scene content.

Vertex Shader
A real-time shader application. A graphics processing function used to add special effects to objects in a 3D environment by performing mathematical operations on the objects' vertex data. Vertex shaders are applied for each vertex and run on a programmable vertex processor.

Voxel
From ”volume element”. A cubic unit of 3D volume defined at a size appropriate to the required resolution, sometimes described as the 3D equivalent of a pixel.

Z-buffer
An area of memory holding the depth (Z) values of each surface in a 3D scene represented at each pixel location at the rendered image.
Z-buffering is the management of image depth coordinates in 3D graphics, usually done in hardware, sometimes in software. It is one solution to the visibility problem, which is the problem of deciding which elements of a rendered scene are visible, and which are hidden. Z-buffering is also known as depth buffering.