Class Name: Diffuse Colour

Superclass - <SEDRIS Abstract Base>

Subclasses

Definition

An instance of this DRM class specifies the diffuse reflectance component of a <Primitive Colour>.

<Diffuse Colour> is

1. dependent on the angle of the lit object to the light source
2. independent of the angle of the lit object to the observer.

Surfaces exhibiting only diffuse reflection (also known as Lambertian reflection) are dull, matte surfaces that appear equally bright from all viewing angles. When a beam of light is reflected from such a surface, the reflected ray is diffused to cover an area, the size of which is inversely proportional to the cosine of the angle that the beam makes with the surface normal.

Diffuse reflection provides what is known as shape from shading information to visual perception; that is, for a surface composed of a single substance and illuminated by a single light source, the shading of the object can be used to compute its surface normals (that is, its shape).

See [FOLEY_VAN_DAM] 16.1.2, "Diffuse Reflection" for further discussion of diffuse reflectance.

Primary Page in DRM Diagram:

• 14

Secondary Pages in DRM Diagram:

• 21

Example

See <Primitive Colour>.

FAQs

Does SEDRIS use the OpenGL lighting model?

No, although the terminology is similar. SEDRIS handles transparency somewhat differently than OpenGL does, among other things. For a description of the OpenGL lighting model, see [OPENGL], Chapter 5 "Lighting".

Constraints

• <<Publishable Object>>

Composed of (two-way)

• one <Colour Data> instance

Component of (two-way)

• zero or one <Light Source> instance
• zero or one <Primitive Colour> instance

Inherited Field Elements