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The SEDRIS Data Representation Model
APPENDIX A - Classes Light Rendering Properties Control Link |
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An instance of this DRM class is a specialized <Control Link> providing the connection between a <Light Rendering Properties> instance and the <Expressions> that are used to determine whether the <Light Rendering Properties> is active and and the value of its candela_value field.
The active_expr_index, candela_value_expr_index, <lower_candela_value_expr_index>, and upper_candela_value_expr_index are 1-based indices into the ordered aggregation of <Expression> instances, and are used to select the specific <Expression> instances that define the target <Light Rendering Properties>' active_light_value and candela_value fields.
Consider a flight simulator database containing an area of terrain representing a city as seen from the air. Some of the <Polygon> instances of this terrain representation have <Light Rendering Properties> with <Twinkling Light Behaviour>, representing city lights. These <Light Rendering Properties> share a <Light Rendering Properties Control Link> that turns them on and off depending on the time of day (on at dusk, off at dawn).
Consider a runway, bordered on either side by a <Line> representing the runway lights. Each <Line> has a <Light Rendering Properties> with <Strobing Light Behaviour>, and a <Light Rendering Properties Control Link> that turns the lights on and off depending on the time of day (on at dusk, off at dawn).
A <Light Rendering Properties Control Link> controls whether the associated <Light Rendering Properties> are on or off, and the candela_value of the <Light Rendering Properties>.
No. The links to the <Light Rendering Behaviour> instances are associations within the transmittal, and associations cannot be changed dynamically.
| SE_String | description; | (notes) |
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This is a text description of the given <Control Link> instance's purpose.
This specifies which component <Expression>, if any, specifies the active_light_value of the target <Light Rendering Properties> instances. If active_expr_index is zero (0), the active_light_value field values of the target instances are not controlled.
This specifies which component <Expression>, if any, specifies the candela_value of the target <Light Rendering Properties> instances. If candela_value_expr_index is zero (0), the candela_value field values of the target instances are not controlled.
This specifies which component <Expression>, if any, defines the lower limit of the candela_value of the target <Light Rendering Properties>. If lower_candela_value_expr_index is zero (0), no lower limit is defined. Note that if candela_value_expr_index is zero, the candela_value field values of the target instances are not controlled, so this value would also be zero.
This specifies which component <Expression>, if any, defines the upper limit of the candela_value of the target <Light Rendering Properties>. If upper_candela_value_expr_index is zero (0), no upper limit is defined. Note that if candela_value_expr_index is zero, the candela_value field values of the target instances are not controlled, so this value would also be zero.
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