Property
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Description
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Class
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Superclass
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Subclass
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Definition
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An instance of this DRM class specifies a single colour, consisting
of individual ambient, diffuse, emissive, and specular components.
See 4.15.3 Colours and lighting.
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Class diagram
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Figure 6.224 —
DRM_Primitive_Colour
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Inherited field elements
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Field name
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Range
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Field data type
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None |
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Field elements
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Field name
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Range
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Field data type
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None |
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Default field values
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Default field values for DRM_Primitive_Colour
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Associated to (one-way) (inherited) |
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Associated to (one-way) |
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Associated by (one-way) (inherited) |
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Associated by (one-way) |
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Associated with (two-way) (inherited) |
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Associated with (two-way) |
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Composed of (two-way) (inherited) |
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Composed of (two-way) |
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Composed of (two-way metadata) (inherited) |
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Composed of (two-way metadata) |
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Component of (two-way) (inherited) |
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Component of (two-way) |
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Constraints
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Clarifications
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None.
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Example(s)
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Consider a <DRM Geometry Model Instance>
instance of a computer monitor, placed on top of a
<DRM Geometry Model Instance> instance
of a desk.
A <DRM Positional Light> instance
affecting the two objects is located so that the illumination is directed
from above. Assume that these instances are present within
an environment simulating an ordinary room.
Each <DRM Polygon> instance within the desk
<DRM Model> instance has a <DRM Inline Colour>
component, which in turn has
a <DRM Primitive Colour> component with both
a <DRM Ambient Colour> component and a
<DRM Diffuse Colour> component. Due to the
<DRM Diffuse Colour> component,
the area of the desk
under the monitor that is visible to the observer appears to be in shadow.
However, the shadowy area is not totally blacked out because the
<DRM Ambient Colour> instance simulates the effect
due to light reflected from the other parts of the environment
(e.g., walls, ceiling, and other objects) that reach
that area.
Consider a <DRM Line> instance used to simulate a line of
runway lights. The <DRM Colour> component of the
<DRM Line> instance resolves to a
<DRM Primitive Colour> instance
consisting primarily (possibly completely) of
a <DRM Emissive Colour> instance
since the <DRM Line> instance is pretending to emit
light.
Consider a collection of <DRM Polygon> instances used to
represent the surface of a sunlit lake. The <DRM Colour>
components of these <DRM Polygon> instances resolve to
<DRM Primitive Colour> instances, each of which consists of
a <DRM Ambient Colour> component,
a <DRM Diffuse Colour> component, and
a <DRM Specular Colour> component.
The <DRM Ambient Colour> component prevents any
<DRM Polygon> instances in shadow from appearing black,
while the <DRM Diffuse Colour> component
provides most of the normal appearance of a lit object. However,
since water is a reflective substance, its colour requires a
<DRM Specular Colour>
component to simulate light reflected from the water.
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