Rendering in Unity is done with Materials, Shaders and Textures.
There is a close relationship between Materials, Shaders and Textures in Unity.
Materials are definitions of how a surface should be rendered, including references to textures used, tiling information, colour tints and more. The available options for a material depend on which shader the material is using.
Shaders are small scripts that contain the mathematical calculations and algorithms for calculating the colour of each pixel rendered, based on the lighting input and the Material configuration.
Textures are bitmap images. A Material may contain references to textures, so that the Material’s shader can use the textures while calculating the surface colour of an object. In addition to basic colour (albedo) of an obejct’s surface, textures can represent many other aspects of a material’s surface such as its reflectivity or roughness.
A material specifies one specific shader to use, and the shader used determines which options are available in the material. A shader specifies one or more textures variables that it expects to use, and the Material Inspector in Unity allows you to assign your own texture assets to these these texture variables.
For most normal rendering - by which we mean characters, scenery, environments, solid and transparent objects, hard and soft surfaces etc., the Standard Shader is usually the best choice. This is a highly customisable shader which is capable of rendering many types of surface in a highly realistic way.
There are other situations where a different built-in shader, or even a custom written shader might be appropriate - such as liquids, foliage, refractive glass, particle effects, cartoony, illustrative or other artistic effects, or other special effects like night vision, heat vision or x-ray vision, etc.
The following pages describe: