Shaders and Texturing - An Introduction to Computer Graphics for Artists - page 184

Fig. 11.4 In this water render test for the alignment illusion project, a water shader has been
applied to particles that defi ne the shape of the water (Model courtesy of Arlon Swaders)

If artistic control is desired, or the shader is stylized, it is possible that an artist
will be asked to make maps for a water shader, but unlikely, because this type of
shader is usually driven by inputs that determine such things as speed, density, wave
height, spray, and other things that do not require map-based information (Gonzalez-
Ochoa et al. 2012 ).

11.4 Texturable Values

There are a number of shading models available, but for the purpose of introducing
readers to texturing, we will focus less on shaders and more on the primary texturable
values in any shader: diffuse color , specularity, transparency, height, and ambient color.

• Diffuse: The color of an object is also known as its diffuse value.
• Transparency: Grayscale maps defi ne 256 levels of transparency.
• Specularity: The degree to which light spreads over on object or is concentrated
into narrow highlights is its specularity. Velvet cloth has a low specular value
because it absorbs most of the light that hits it, but glass has a high specular value
because it absorbs very little light.