Table 6.38— DRM_Blend_Directional_Light
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Property |
Description |
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Superclass |
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Class |
· <DRM Blend Directional Light> |
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Subclass |
· none |
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Definition |
A <DRM Blend Directional Light> is a light whose intensity varies depending on your position to the light's location, direction, and shape. This light takes the shape of a pyramid, subdivided by two planes. These planes are based at the pyramid's apex and extend towards the base. They subdivide the pyramid into upper and lower sections with a blend section in between. The upper section receives the primary color while the lower section receives the secondary color. The blend section blends between the primary and secondary colors depending on the viewing position. |
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Example(s) |
·
The <DRM Blend
Directional Light> has both a primary and a secondary color. The
component has horizontal_width = 90 and vertical_width = 90. The upper_plane_angular_offset
is 1.5 and the lower_plane_angular_offset is -2.5. If position of the viewer from the light direction vector is 1.5 degrees in the vertical direction, towards the positive end of the vertical axis vector, the viewer will see the primary color, since he is at the upper edge of the blend section. As he moves from here along the vertical axis vector, towards the negative end, the amount of primary color decreases as it is blended with proportionally increasing amounts of the secondary color. This is because he is moving within the blend section of the cone, from the upper edge to the lower edge. Once he reaches -0.5 degrees from the light direction in the vertical direction (i.e., towards the negative direction of the vertical axis), he sees the primary and secondary colors blended in equal amounts as he is now in the middle of the blend section. As he continues to move in the same direction, the amount of primary color continues to decrease proportionally as the amount of secondary color increases. By the time he reaches -2.5 degrees from the light direction, he sees only the secondary color, as he has now reached the lower edge of the blend section. If his position from the light direction vector is -10 degrees in the vertical direction (i.e., towards the negative end of the vertical axis vector), he sees the secondary color as he is inside the vertical width, in the lower section of the cone. If the position of the viewer from the light direction vector is -50 degrees in the vertical direction (i.e., towards the negative end of the vertical axis vector), he sees nothing, as he is outside the pyramid. |
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Inherited field elements |
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Field elements |
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Associated to (one-way) (inherited) |
· none |
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Associated to (one-way) |
· none |
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Associated by (one-way) (inherited) |
· none |
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Associated by (one-way) |
· none |
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Associated with (two-way) (inherited) |
· none |
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Associated with (two-way) |
· none |
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Composed of (two-way) (inherited) |
· one <DRM Lobe Data>3 · one <DRM Location> |
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Composed of (two-way) |
· none |
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Composed of (two-way metadata) (inherited) |
· none |
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Composed of (two-way metadata) |
· none |
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Component of (inherited) |
· one or more <DRM Light Rendering Properties>s |
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Component of |
· none |
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Constraints |
· none |
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Notes |
1 This value defines the angular offset of the plane that lies between the upper and blend sections. It is measured in degrees (-180 to 180) from the lobe's light_direction vector, along its vertical_axis vector (in the same way as the vertical_width). The resulting upper section of the light is taken to be between the plane and the positive end of the vertical_axis vector. 2 This value defines the angular offset of the plane that lies between the lower and blend sections. It is measured in degrees (-180 to 180) from the lobe's light_direction vector, along its vertical_axis vector (in the same way as the vertical_width). The resulting lower section of the light is taken to be between the plane and the negative end of the vertical_axis vector. 3 The lobe shape. |
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Class diagram |